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D. Buskulic LAPP / Université de Savoie

1. vega v new VFrameChannel file SMSdemoDB root If you want to see the contents of the frames do as before vega v gt Print You will see that there is a slow monitoring station called MYGOSMS that contains two variables VF1 and VI2 The special treatment we have to apply in order to gain a simple yet efficient way of dealing with SMS data is to build a special object called an ntuple that will contain all this data We developed a particular ntuple that differs from the standard ROOT one in that it is adapted to our needs You can think of a ntuple as a list of all the sms data put in a tree like structure NTuple Entry 1 Entry 2 Entry 3 Entry 4 f 6F Parameter 1 Parameter Parameter 3 The difference with a simple array is that each leaf of the tree can be any kind of object even a tree itself This leads to a hierarchy structure like in a directory structure for a file system In fact these more general ntuples are called trees and we will not yet work with them In simple ntuples each leaf is a single float parameter So to build a ntuple starting from the slow monitoring data one can do vega nt v gt ExtractSMS nt MYGOSMS VF1 MYGOSMS VI2 400000000 5000 The first parameter nt is the name of the ntuple Then MYGOSMS VF1 MYGOSMS VF2 is the list of SMS variables one wants to extract Instead of telling every variable you can specify only the name of a sl
2. In order to access sequentially all the vectors of interest satisfying a selection expression one has to have an object that will point to the time intervals of interest So came the idea of condition sets Once a condition set has been defined one can use it to extract vectors that are recorded at the corresponding time The method of VFrameChannel to do so is FrVect GetNextVect Text_t nameofvect VConditionSet condset It returns a vector of type FrVect given its name and type First the condition set condset jumps to the next time interval satisfying its internal conditions Then the vector is extracted that spans this time interval The string nameofvect indicates the type adc proc sim and the name of the series to be extracted The convention for the format is type name For example adc IFO_DMRO is a good format If only the name is given the groups of series in the frame will be searched in the order adc proc sim for that name If more than one identical name was defined in the frame the first found series with that name will be used For example vega vect fc gt GetNextVect adc IFO DMRO condset The search will be governed by the condition set condset The returned vector of type FrVect will be the next vector that satisfies the internal selection expression of the condition set condset This method has been designed to be called sequentially in a loop One warning the memory for returned v
3. The triggers structures of type FrTrigData in the FrameLib are converted to more general objects called conditions This will allow to use in the future as conditions other information such as slow monitoring data or quality information The user may even add his own conditions without copying the whole files just to adda FrTrigData structure A simple scheme of the database was given above This scheme is now enhanced by the addition of condition trees and an index for fast access Entry 11 Condition trees 1 entry 1Condition 99 1 2 2 Extracting metadata with a condition There are two ways of extracting metadata that satisfy a given condition directly or sequentially The direct method will be used if a particular frame which approximate time is known is to be extracted The sequential method is used if one needs to process or view sequentially all the frames that correspond to a given selection expression 1 2 2 1 Direct methods The method of VFrameMetaDB that allow a direct conditioned access to metadata is GetNextFrame VMetaData meta Double t time char selection This method extracts a metadata at an absolute time selection is a selection expression referring to conditions existing in the database such as Trigl amp gt 50 amp amp Trig2 amp gt 2 Example vega meta vd gt GetNextMeta time Trigl amp gt 50 amp amp Trig2 amp gt 2 the search will begin from time time The metadata meta w
4. V 4 3 Getting general information about the information database and it s contents V 4 3 1 Getting the start time of the information database To get the start time of the first frame indexed in the information database files metadb bookkeeping database to which a frame channel is connected one has to use the VFrameChannel method double GetStart For example if fc is a valid frame channel vega fc gt GetStart will output this start time while vega st fc gt GetStart will put it in a double that may be reused V 4 3 2 Printing information about the frame channel One can get some information about the frame channel and it s connected database by using the VFrameChannel method void Print For example if fc is a valid frame channel vega fc gt Print This will show a summary information about the information database and will print the dump of the first frame at the end This may be used to collect names of vectors etc V 5 Dealing with selected or triggered data V 5 1 Condition information in the information database A frame channel is connected to an information database that may have various types However every such database is supposed to keep information about triggers conditions and other such as quality words that allow a user to select a subset of all the frames When the database is build by reading the frame files or getting information from them the trigger information containe
5. cs fc gt CreateConditionSet Trigl amp gt 50 amp amp Trig2 amp gt 1 The object fc is a valid frame channel connected to an info database Each information database has a particular type of condition set So the frame channel will ask the info database to create a new condition set adapted to it s needs All condition sets particular to a database derive from a common parent called VConditionSet This is the type of object returned by the CreateConditionSet method In other words each database acts as a factory of condition sets that will be used only by itself and the frame channel The user may stop here since the extraction of all the successive frames or vectors satisfying the selection expression is described in the paragraphs below and do not need any other manipulation of the condition set Nevertheless for the interested reader we can play with it to understand the behavior When first build a condition set points to the beginning of the info database One can make it jump to the next set of valid conditions by using the method NextFormSet vega cs gt NextFormSet Using it repeatedly the set will point to the successive selected time intervals in dark in the following figure NextFormSet NextFormSet NextFormSet NextFormSet gt lt Length of one frame time Actually the selected intervals are not forced to have limits at the beginning or end of a frame This depends on the start
6. only the metadata corresponding to these files are searched The corresponding metadata is sent back to the frame channel that will access the desired frame in the relevant file or reconstruct the desired vector and give it to the user The metadata is kept in a container called Tree introduced in ROOT and specifically designed to handle big amounts of data and access it quickly The tree structure can also contain conditions for frame access 1 1 2 Creation of a metadatabase VFrameMetaDB char filename char mode char framefilenames char opt To create a local database we need to create a database object of class VFrameMetaDB At the same time we can build it looking for frame files As for example in vega vd new VFrameMetaDB demoDB root CREATE we call the VFrameMetaDB constructor The first parameter is the name of the database file The second one is the mode with which we open the database Here it is opened in CREATE mode since we want to build it the third parameter is the path to the directory containing the frame files Here it is meaning the local directory You can put whatever path you like and specify particular files directories with wildcards The search is by default recursive all the contained directories will be searched recursively If you want to turn this option off add a last parameter and specify S That s it The amount of time needed to index the files depends on t
7. the following options an OR is made of the three previous flags CXX command to invoke the C compiler CC command to invoke the C compiler ld command to invoke the linker prefix gives the prefix path used for root cflags outputs the flags used by the C C compiler to compile root and VEGA ldflags flags used when invoking the linker soflags flags invoked for creation of a shared object coptflags outputs the optimisation flag used by the C C compiler to compile root and VEGA includes output include options used when compiling an object for VEGA following the previous flags nonew do not include libNew for the following options libs output libraries options used when compiling an object for VEGA following the previous flags glibs output libraries used by VEGA or ROOT when making an application using the ROOT GUI defines output defines that were used for compiling VEGA following the previous flags version gives the VEGA version The flags may be combined to give a complete command and characters that do not represent any flag are output as is Examples gt vega config cxx c toto cc g c toto cc One can build a complete command to compile a source code gt vega config cxx cflags includes c toto cc g fPIC fsigned char I home toto vega src include I virgoApp Fr v4r25 sre I home toto root include I home toto fftw include c toto
8. Frame Channel V 4 2 1 Extracting frames Frames are extracted through the frame channel fc opened as in the previous paragraph with FrameH GetFrame Double_t time FrameH GetFrameR Double t relativetime The first method extracts a frame at an absolute time the second at a time relative to the reference time see chapter Dealing with time As in vega FrameH frame fc gt GetFrame time where time is a double expressing a time that is contained in the frame This method sends back a pointer to a well known FrameH structure Once one has extracted one frame it is possible to extract the next one or the preceding one in time FrameH GetNextFrame For example vega frame fc gt GetNextFrame or FrameH GetPreviousFrame For example vega frame fc gt GetPreviousFrame Be careful while GetFrame is checking to see if the requested time is really contained in one of the frames of the database GetNextFrame and GetPreviousFrame do not They will simply return you the frame that is the next or previous one in time in the database even ifit s years away V 4 2 2 Extracting vectors of any length Sometimes one would like to extract a vector which length is smaller than the one of a frame or a vector that is spanning two or more frames One can extract such a vector with FrVect GetVect Text_t nameofvect Double t start Double t length Option t opt FrVect GetVectR Text_t
9. SetFillStyle Style_t styl 0 const char name SetLineColor Color_t color 1 const char name SetLineStyle Style_t styl 0 const char name SetLineWidth Width_t width 1 const char name nn SetLabelColor Color_t color 1 Option_t axis X const char name SetLabelFont Style_t font 62 Option_t axis X const char name SetLabelOffset Float_t offset 0 005 Option_t axis X const char name SetLabelSize Float_t size 0 04 Option_t axis X const char name SetMarkerColor Color_t tcolor 1 const char name SetMarkerSize Size_t msize 1 const char name SetMarkerStyle Style_t mstyle 1 const char name SetNdivisions Int_t n 510 Option_t axis X const char name SetTickLength Float_t length 0 03 Option_t axis X const char name The arguments are self explanatory except the name This is the name of the plot on which the change of attribute should be done If name the change is applied to the last plot drawn by gVM Examples gVM gt SetMarkerSize 1 2 will change the marker size of the last plot drawn gVM gt SetLineColor 3 MYGO ADCl will change the line color of the plot named MYGO_ADC1 VII 2 6 Management of the plots produced The manager decides at drawing time what is the dimension of the plot produced depending on the dimension of the data in the frame vector If the frame vector is 1 dimensional it produces a VSPlot an
10. The Data Display will be opened with the main browser window showing the channels inside frames from the frame channel IX 2 2 Interaction with the produced plots Once the user has made the desired plots he is able to interact with these plots from inside VEGA A global variable named gDataViewer represents the data display One can interact with it with the following methods gDataViewer gt GetPlot i will return a TObject corresponding to the plot in the pad n i This object should be 74 casted to a TH1F or a TH2F depending on the type of the plot in the corresponding pad like in vega hl TH1F gDataViewer gt GetPlot 3 Reminder the pads are numbered from up to down and left to right like in Pad number 1 2 3 4 5 6 The canvas created by the data display is called gDDCanvas and is accessible globally after its creation One can for example put the y scale of the pad number 2 in log with the commands vega gDDCanvas gt cd 2 vega gPad gt SetLogy 1 Reminder gPad always points to the current pad IX 2 3 Using configuration files produced by the standalone dataDisplay application The standalone Data Display application produces configuration files cards files that a user may wish to reuse This may be done if a cards file points to files not to online Cm producer by starting the data display interactively with the dataDisplay command and then loading the cards file from the Config Me
11. as before but without erasing the values of the histogram before filling It will just add those to the existing ones That way one can span more than one series for one given histogram VII 2 4 2 Drawing selected contents or distribution of a frame One can draw a selected adc or processed or simulated data without having to extract it first from a frame Simple drawing of a vector 1D or 2D contained in a frame void Draw FrameH frame Text_t typeAndName Float_t offset Float_t dur 1e20 Option_t option where frame is a frame of type FrameH that has been read from a file typeAndName is a pointer to an array of char that describes the type adc proc or sim and name of the frame element to be extracted and drawn It has the following structure type name For example adc IFO DMRO is a good format It will look for the adc data of the adc named IFO_DMRO It is possible to give only the name if there is no ambiguity In that case adc data will be searched first for that name then proc and then sim data If more than one identical name was used the first found series will be extracted offset is the offset from which the drawing starts with respect to the starting value of the vector i e series dur is the length of the drawn part of the vector i e series option is an option string that is passed to the plot that is drawn This is equivalent to the TH1 class drawing options The reader can go to
12. cc One clearly sees that the result may not be simple and that it depends on the particular configuration of the system used The vega config command and flags are the same however and insure that one is able to compile his program the same way whatever the system The vega config script only outputs the command but does not execute it In most shells putting the command between back quotes will execute the command and then the output of the command gt vega config cxx cflags includes c toto cc Now it is possible to build relatively easily any program First try with the ones provided in the test directory XIII 3 3 Using only a subset of capabilities To allow saving of resources one may be willing to use only relevant parts of the VEGA ROOT system For example use only metadatabase without graphics and display There are three flags of the vega config utility that restrict the output to only relevant parts of a particular set metadb set only output parameters includes libraries relevant to metadatabase for the following options display set only output parameters includes libraries relevant to display for the following options signal set only output parameters includes libraries relevant to signal for the following options Try yourself the following commands and see the difference gt vega config includes libs gt vega config metadb set includes libs XIII 4 Building
13. eeu eeneeaeeas 27 IV 3 C notions used operators new and delete 29 V Accessing and managing Gravitational Waves data 31 V 1 Accessing frames through the Framelib s 31 V 2 General scheme for data access shine ccotebadetanvigh cdonabadetboviad canitbaduaessige ist 31 V 3 Different information databases for different uses 32 V 3 1 Simple access direct files nnion ess cadena lar a i a t a i 32 V 3 2 More complex case metadatabase cc ia n eee E E E TEER 33 V 3 3 Full case bookkeeping database 33 V 4 Access to the data through a Frame Channel 33 V 4 1 Opening a frame channel and connecting to an information database 33 V 4 2 Accessing data through a Frame Channel 34 V 4 3 Getting general information about the information database and it s contents 36 V 5 Dealing with selected or triggered data 37 V 5 1 Condition information in the information database 37 V 5 2 CONdition Sets nan nn een wade a eee Ta N ne D Lt ete 37 V 5 3 Extracting frames with a condition 39 V 5 4 Extracting vectors with a condition ss 40 V 5 5 Getting information about condition Sets 00 0 cece ec seeeeeceeeeeeeeee eee eeaeeaeeas 42 V 6 N tuples adapted for GW data analysis 43 V 6 1 Building VNtuple sens ner RS SR te An a a tn RE nn ti 44 V 6 2 Filling an
14. it is convenient to plot the start time of the vector it is also interesting to have the numbers on the axis expressed in seconds or minutes or hours or why not days By default the numbers displayed on an axis are expressed in seconds since the start time of the vector One can set the axis so that time is expressed in seconds minutes hours days VII1 2 2 1 Interactively setting time display on the axis Interactively one can set it by using the SetTimeDisplay entry of the popup menu of the axis CenterTitle SetRange SetTimeDisplay SetTimeF ormat UnZoom SetName aoe The result is the following The careful reader will have noticed that the second displayed on the axis is the one of the starting time also displayed 08 09 92 15 07 09 This is general the time displayed on the axis is the last part of the absolute time so one can easily and visually connect it with the starting time of the vector Furthermore the transitions from one minute to the next or from one hour to the next are correctly handled we hope so The format of the time display may be set with the SetTimeFormat entry of the popup This format is the same as the one used in the standard C function strftime It is a format string that contains For the date ga Abbreviated weekday name Sb Abbreviated month name sd Day of the month 01 31 sm Month 01 12 Sy Year with
15. little bit familiar with C and I will introduce the basic C notions when needed This is not intended to be a C guide it s too huge of a task but ROOT is a good environment to learn C and it would be a pity not to use it that way So I will try to be as simple as possible from the C point of view Each example will be followed by the explanation of the underlying C concepts used enough to understand the various commands I will also introduce some ROOT related specific concepts after each example All suggestions are welcome and you can reach me buskulic lapp in2p3 fr 1 3 Installation of VEGA ROOT The installation and build of the VEGA software is described in Installation of ROOT and VEGA on the VEGA site 1 4 How to find information The main source of information for ROOT is ROOT main site http root cern ch There is a lot of information online and a User s Manual In particular one can find all the source code of ROOT organized in a very nice way and a searchable archive of the mailing list devoted to ROOT roottalk If you have a question there is a slight chance that someone asked it before you For VEGA the information can be found at the VEGA site http wwwlapp in2p3 fr virgo vega Il An interactive session In this first chapter we will concentrate on giving the reader a feeling of the possibilities of the framework We will use standard ROOT as well as VEGA specific examples The user actions
16. nameofvect Double t start Double t length Option t opt The first method extracts a frame at an absolute time the second at a time relative to the reference time see chapter Dealing with time As for example vega FrVect vect fc gt GetVect adc IFO DMRO start length It returns a vector of type FrVect given its name and type The vector starts at time start and has a length length both are doubles Vectors extracted through the frame channel will be concatenated as needed to obtain the desired vector The string nameofvect indicates the type adc proc sim and the name of the series to be extracted The convention for the format is type name For example adc IFO_DMRO is a good format If only the name is given the groups of series in the frame will be searched in the order adc proc sim for that name If more than one identical name was defined in the frame the first found series with that name will be used The extracted values of the vector are casted to double by default This behaviour may be changed If the option string opt nocast the extracted vector retains the original data type opt is set by default to empty no option V 4 2 3 Extracting n tuples of SMS data As was seen in the chapter IV Hands on VEGA in order to manipulate slow monitoring data one has first to extract them in a ntuple This is done with the VFrameChannel methods VNtuple ExtractSMS Text_t nam
17. ss 89 XII 2 Compiling a script and making a shared library of it 89 XIIL 2 1 Preparation of the scriptie anne it tentes st tenta tdi taste ht 90 XT 22 Compiling the Scripts sr A nn dns ee staan doe Areas vay stat 90 XMS Limitations sses nania iala a ay dela dates enr tena ddateses aa Aa i oa senses des 91 XIS Building a standalone executable ssssss 91 XII 3 1 Building an executable that is linked with the ROOT and VEGA libraries 91 XII 3 2 Options of the vega config utility 91 XII 3 3 Using only a subset of capabilities 2 00 ccc cec cece eee eeneeaeeeeee eee seeeeaeeaeeas 93 XII 4 Building a general shared library usable with VEGA ccc eeceeccecece eee eeeeeeneeneens 93 Appendix A Local metadatabase structure and principles 95 I 1 Metadatabase for easy data access 95 FET Principle andsstructures aeaea tariias obo a tata tete ane de rm time bien 95 1 1 2 Creation of a metadatabase sise 96 1 1 3 A ess to metadata eina Mmes enter dena saa Suegedet e a chlae saaseteotet es 97 1 1 4 Getting general information about the metadatabase and it s contents 98 I 2 Dealing with selected or triggered data 99 1 2 1 Condition information in the metadatabase eeeesseeeesseeseserrrserrrresrrrirrerereresree 99 1 2 2 Extracting metadata with a condition ce cece cence nee eeeeeeeeeee eee eeueeaeeaeeas 100 Table of Conte wt ssccssiecsesse
18. the address http root cern ch to see the list of options in the drawing of a TH1 see Classes and Members Reference Guide Options e The ones of the TH1 class for example same which superimposes a plot to a previous draw e sameti does a similar superposition but respects the time i e will shift the plot so that it s time and the one of a previously drawn vector coincide If offset and dur are omitted the whole vector is drawn It is also possible to specify only the drawing option A VSPlot is drawn in the current pad or canvas The address of this plot is added to the list of plots managed by this manager The name of the plot becomes the name of the FrXXXData extracted XXX Adc Proc or Sim Examples Suppose a FrAdcData vector MYGO_ADC contains data starting at t O and has a duration of 1 s with 50000 samples in a frame called frame gVM gt Draw frame adc MYGO_ADC will draw the entire series gVM gt Draw frame MYGO_ADC 0 3 0 2 will draw the series starting at th 0 3 s for a duration of 0 2 s which represents 10000 samples Since no type adc proc or sim was given it will search for the first data occurring with this name in the frame Example of such a plot 54 Fe cl Jof x File Edit View Options Inspect Classes Help gVM gt Draw frame MYGO_ADC same will draw the entire series on the same plot as a previous draw Drawing the distribution histogram of the data o
19. the metadatabase name but this is the default so it is not mandatory The instructions to extract a frame or vector are the same as in the direct file access case and will be explained in the following paragraphs The only difference is that one is assured not to have any problems in case frames are mixed in various files or one wants to use a selected triggered set of frames V 3 3 Full case bookkeeping database In the case of VIRGO a bookkeeping database is build continuously as frames come from the detector A case is foreseen for connecting a frame channel to such a database The prefix is bkdb This will be described in future versions of VEGA V 4 Access to the data through a Frame Channel V 4 1 Opening a frame channel and connecting to an information database VFrameChannel char dbname To create a frame channel we need to create an object of class VFrameChannel At the same time we can build it looking for an information database As for example in vega fc new VFrameChannel demoDB root we call the VFrameChannel constructor The parameter is the name of the info database It may be preceded by the type of database e file for direct file access The frame files themselves will give the meta information e metadb for a metadatabase as described in the next paragraph bkdb for an ORACLE bookkeeping database feature not yet available but in progress V 4 2 Accessing data through a
20. time and length of the triggers and is not dependent on the frame length Once the condition set has jumped to the next selected interval one may retrieve its start and end time vega start cs gt GetIntersectionStart vega end cs gt GetIntersectionEnd Why is the word Intersection appearing here Each selection formula used in a condition set references one or more conditions or triggers For example the formula above references Trig1 and Trig2 Each of these conditions has a start time and an end time But in the case where there is more than one referenced condition the start and end time of each of them may not coincide So when searching a match for the selection the first thing done is to search for an intersection of all the referenced conditions Trig Trig2 Intersection gt time In the example above we have only used a sequential search getting all the interesting intervals It is also possible to jump directly to the interval that is following immediately a specified time vega cs gt NearestGEFormSet time where time is in GPS format double seconds nanoseconds V 5 3 Extracting frames with a condition There are two ways of extracting frames that satisfy a given condition directly or sequentially The direct method will be used if a particular frame which approximate time is known is to be extracted The sequential method is used if one needs to process or view sequentia
21. 1 Draw error bars with perpendicular lines at the edges E2 Draw error bars with rectangles E3 Draw a fill area through the end points of the vertical error bars E4 Draw a smoothed filled area through the end points of the error bars EL Draw a line through the bin contents Pp Draw current marker at each bin A Draw histogram with a at each bin The following options are supported for 2 D types ARR arrow mode Shows gradient between adjacent cells BOX a box is drawn for each cell with surface proportional to contents COL a box is drawn for each cell with a color scale varying with contents COLZ same as COL In addition the color mapping is also drawn CONT Draw a contour plot same as CONTS FR s y O1 CONTO Draw a contour plot using colors to distinguish contours CONT1 Draw a contour plot using line styles to distinguish contours CONT2 Draw a contour plot using the same line style for all contours CONT3 Draw a contour plot using fill area colors FB With LEGO or SURFACE suppress the Front Box BB With LEGO or SURFACE suppress the Back Box SCAT Draw a scatter plot default VIII Dealing with time In nearly all physics experiments where the time is an important variable the use of GPS Global Positioning System is generalized This allows to get a microsecond precision clock synchronized throu
22. 1 gt cd 1 select the first pad gVM gt Draw frvl cl gt cd 2 select the second pad gVM gt Draw frvSeis Gets the needed vectors and draws them Second the same plots superimposed Gets the needed vectors again but zooming on the region of interest frv2 vd gt GetVect adc MYGO ADC1 400000010 24 0 06 frvSeis2 vd gt GetVect adc MYGO Seis 400000010 24 0 06 Draws them in the second pad superimposed on top of each other cl gt cd 3 gVM gt Draw frv2 gVM gt Draw frvSeis2 same To show the result when displaying a the same peak but in a very fancy way well this is all a matter of taste with the macro peak2 C here is the result M GO_ADCi RMS _ 27 69 Avy L 36 2 RMS 558 4 XII 2 Example 2 scrolling data 81 This example shows how to display a channel extracted from a database with scrolling one second at a time The channel is extracted in the form of FrVect vectors Each extracted FrVect does not match the length of the frame it belongs to In fact the user should not care about that The example is in the file scroll c This simple example opens a demo local database and plots a vector The vector is scrolled 1 s at a time nvecmax times The extraction of the vector shows that one can select a vector without having to think about the frame boundaries The length of the vector is arbitrary and is only limited
23. ANNEC lapp Visual Environment for Gravitational waves data Analysis vor95 D Buskulic LAPP Universit de Savoie Introduction VEGA Visual Environment for Gravitational waves data Analysis is designed to be a framework in which one can analyze data coming from interferometric gravitational wave detectors This data is supposed to be in the Frame format which was agreed upon between the two gravitational wave detection experiments VIRGO and LIGO This data format is now also used by other such experiments VEGA is based on the ROOT framework developed at CERN by R Brun and F Rademakers There are numerous other contributors to this work and I apologize for not citing them all VEGA is an environment containing The entire Framelib http wwwlapp in2p3 fr virgo FrameL which is a set of functions written in C that enable access and manipulation of frame data files A set of Manager classes that makes the heart of the framework especially doing the interface with the Framelib and Framelib objects frames frame files frame vectors A set of frame data handling classes that allows the user an easy access to data contained in a big number of files A set of algorithm classes that defines a standard form for algorithms thus enabling easy manipulation and inclusion of these algorithms They can be used in drawing multiprocessing etc So VEGA extends ROOT in the field of signal processing We h
24. CINT to test the given examples Before that exit the previous ROOT session go to the directory VEGA vegatutorial launch ROOT VEGA and load into the environment the tutorial macro vtutorial C vega L vtutorial c The raw command L loads a macro into the interpreter environment You can then use all the functions classes objects defined inside it C extends C with the notion of class If you re used to structures in C a class is a struct that is a group of variables that are related which is extended with functions and routines specific to this structure class What is the interest Consider a struct that is defined this way struct Line float xl float yl float x2 float y2 This structure is defined in vtutorial C so you don t have to define it yourself It represents a line to be drawn in a graphical window x1 y1 are the coordinates of the first point x2 y2 the coordinates of the second point In standard C if you want to effectively draw such a line you first have to define a structure and initialize the points you can try this Line firstline firstline xl 0 2 firstline yl 0 2 firstline x2 0 8 firstline y2 0 9 This defines a line going from the point 0 2 0 2 to the point 0 8 0 9 To draw this line you will have to write a function say LineDraw Line 1 and call it with your object as argument LineDraw firstline In C we would not do that We would instead define a
25. N tuple and getting data 45 V 6 3 Drawn Say orate E E A ee deka te nd Te SARA do UD SE ane Sn een borate Le 46 VI Analysis of data coming from a frame channel the selectof iscssnsssscssnccnnccnmenssesennssceendencseceaiesuucntencsecon causes ee T A VII Representing Gravitational Waves data mn 49 Vike S ries plots una date E enh eee oe de pete neue nel douter 49 VIL2 Graphical managers of frames ieaie ania ana ine a a e a a aA 49 VIL2ZL Definition Of man gers ionn A E E EE AN E NE a 49 VII 2 2 Building a manager the global gVM see eeueeaeeas 50 VIL2 8 G n ral Use rene E E A we eee a Enr 50 VIL2 4 Drawing methods yes nn sat E E ATA dt de de ste ten ne met Sedan 50 VIL2 5 Change of the plots attributes ccc cec eee eee eeaeeaeeaeeeeeeeee eee eeaeeaeeas 59 VIL2 6 Management of the plots produced 60 VIL3 Representing slow monitoring data ss 60 VIII Dealing with time mmmmmmmmmanennannanennannnnennnnnnnnnnnnnnnnn 06 VILI Time when accessing data ss 66 VILL Therreferen ce time ess earls as na marine ete de don ant eee obey 66 VIIL 1 2 How to s ta reference time icsiccceicssieesaeessecose ena gst ecaneeeteesaeeeoeene eres teateeetecssensees 66 VUI 2 Time when outputting information ss 67 VIIL 2 1 Plotting frames or vectors start time 67 VIIL 2 2 Plotting tim
26. ONT3 Draw a contour plot using fill area colors CONT4 Draw a contour plot using surface colors SURF option at theta 0 LIST Generate a list of TGraph objects for each contour ARR Arrow mode Shows gradient between adjacent cells BOX A box is drawn for each cell with surface proportional to contents COL A box is drawn for each cell with a color scale varying with contents BB With LEGO or SURFACE suppress the Back Box FB With LEGO or SURFACE suppress the Front Box AH Draw plot but not the axis labels and tick marks for LEGO and SURF options Ze Draw a color scale on the right of the plot for COL and CONT options only SCAT Draw a scatter plot default Since an image is attached to a given frame and does not span two or more of them one cannot for the moment extract a 2D vector spanning two or more frames One could indeed think of it for time frequency vectors but it is not yet done VII 2 5 Change of the plots attributes Once drawn it is possible to change the plots attributes like line color or fill style directly using gVM The following methods are available GetXaxis const char name GetYaxis const char name GetZaxis const char name Return a pointer to the specified axis object allowing to manipulate it SetBarOffset Float_t baroff 0 5 const char name SetBarWidth Float_t barwidth 0 5 const char name SetFillColor Color_t color 1 const char name
27. Object This class contains everything that is shared by all the classes in ROOT Especially it handles e the object I O so one can send any object to a file without writing the corresponding code comparing two objects enabling searches sorts etc e graphics hit detection e notification between objects so they can talk to each other to name the most important ones 11 3 An example of a macro Let s try now to see how we can write a simple macro As we ve said this is just C C code Open the editor of your choice and look at the macro named vfill_histo C As a matter of convention all macros are suffixed by C The source code has a cxx or cc suffix vfill_histo C is the following code Create and fill a histogram with random s from a Gaussian distribution See http root cern ch root HowtoHistogram html for a brief description of how to use histograms in ROOT gROOT gt Reset THIF is the equivalent of HBOOK1 The fill data are 32 bit float points and weights are 64 bit fp printf Creating Histogram n THIF hl new THIF h1 1 D Gaussians 100 8 8 printf done n The ROOT CINT extensions to C The declaration of hl may be omitted when new is used So hl new TH1F will correctly create an object of class THIF gRandom gt SetSeed Raw C types are typedefed Float_t xgauss printf Filling Histogram n for Int_t i 0 i lt 10000 i x
28. This is described in the chapter How to compile your own code for VEGA or use the VEGA libraries in your code at the end of the manual lll Hands on VEGA Before describing extensively the VEGA classes methods and objects it would be interesting to put directly hands on the environment and see some of it s capabilities from the point of view of gravitational waves data analysis Concepts will be introduced as needed 111 1 Preparation So let s imagine someone has a set of frame files that he she wants to analyze We will first build some tutorial files Copy to your home directory the vegatutorial directory that is in the VEGA package Then cd to this directory and launch a VEGA session Then in this session execute the create_testfr C script vega x create_testfr C This will create files containing a few test frames starting at time GPS 400000000 097 till the time 400001475 097 You will see some plots of the contents of these frames at the same time Then a file named SMSdemo F containing frames with only slow monitoring test data will be produced 11 2 Opening a Frame Channel Now that we have a few frame files we will need to access quickly a subset of them if possible without bothering with frame boundaries just giving the start time and length of the piece we want In VEGA the central notion to do such things is the Frame Channel Usually the information about the data called metadata location du
29. This method toggles the start time display A call to it vega gVStyle gt SetStartTimeDisplay 0 will toggle off all subsequent displays i e no plots will have their start time plotted from then on VStyle SetStartTimeXOffset float offset The position of the time string in the plot is fixed This method sets the offset of the string with respect to the left side of the pad A call to it vega gVStyle gt SetStartTimexOffset 0 04 will fix the string position horizontally for all vectors drawn after this call The default value is 0 02 VStyle SetStartTimeYOffset float offset This method sets the offset of the string with respect to the bottom of the pad A call to it vega gVStyle gt SetStartTimexOffset 0 04 will fix the string position vertically for all vectors drawn after this call The default value is 0 02 Once a VSPlot is drawn similar methods exist to change the position of the start time if needed They are used in exactly the same way as the VStyle ones except you need to have a valid pointer to a VSPlot VSPlot SetStartTimeDisplay true_or_false VSPlot SetStartTimexOffset float offset VSPlot SetStartTimeYOffset float offset For instance if vs is a pointer to the last drawn plot that you get via gvStyle gt SetStartTimeXOffset the following vega vs gt SetStartTimexOffset 0 04 69 will change the x offset of start time VIII 2 2 Plotting time on time series axis While
30. a A R O E A 1 I 2 Objectives Of this documente imin das A T E E E AA 2 I 3 Installation of VEGA ROO Piris ue cds nn a e deste ode ove a cut Ea de ue a Ea ren Sate steeds 2 1 4 How to find information Pasmo eeka tage aaa tees cate GN anita dase nn tian cat ee nat de 2 An interactive SeSSiON mmmnnnnnnnnnnnnnnnnnnnnnnnnnnnnnmmmmmmmmmnnnnnnnn D ME Basicintrinsic operations sn dents nt RS LR eu rte Mee eee 3 I 2 The interpreter CINT graphical interaction through a few examples 3 IL2 1 First very Simple example sce vias naar dade agen evade ara and en dette dis 3 IL 2 2 Graphical output example iii cccscceesesneatesteutazeesseaedecteasarnes seaageoseeserendeenagnsageeeeee ees 4 1 2 3 Classes methods and constructors sisi 5 11 2 4 ROOT related specifics tante tannins gutdagited a nent seed dean saute esse 6 11 2 5 Graphical output example User interaction ccc cece eeeneeneeeeeeeee eee eeaeeaeeas 6 11 2 6 Second example Building a multi pad canvas 8 11 2 7 Inheritance and data encapsulation 9 11 2 8 ROOT related specilicS sas tan eat ae ee a A Sa ue 10 11 3 Anvexample ofa Macro nn a O deve annees den ent ss ee ne dune 10 11 3 1 C notions used method overloading cece c cece eee eeneeeeeeeee sense eeaeeaees 13 I 4 How to Compil a Macro P isssscccscociecssapesis
31. a general shared library usable with VEGA 94 Appendix A Local metadatabase structure and principles 1 1 Metadatabase for easy data access 1 1 1 Principle and structure From the user s point of view the analysis environment should allow her him to access simply any vector or frame that is contained in a set of frame files even remotely One should also be able to access vector not caring about frame boundaries It should also be possible to make accesses conditioned by some trigger slow monitoring value or user defined condition Furthermore one should be able to manage a set of files that is as big as possible of the order of 1 TB or more The option chosen in VEGA to solve this problem is to build a database that contains metadata about frames and indexes these frames The structure of the database is drawn on the following figure 96 Time Hash Table Frame Metadata Tree Frame files 1 Entry 1 Frame Descriptor oni itions BAUNA E rime ee sire Entries i3 i4 EEEF C0C09090 end time The complete frame information is kept in the frame files while the database serves as an index to access them The access is a multistep process First one gives the starting time of the vector one wants to a frame channel This starting time is given to the metadatabase and is used to determine with the help of what is called a time hash table the frame files that possibly contain the desired information Then
32. ade with the VFrameChannel MakeSelector method vega fc gt MakeSelector selectorname This creates skeleton source code of a class named selectorname in two files selectorname h and selectorname C The file selectorname C is the only relevant for the user The generated class has a few initially empty methods that the user should fill e void Begin VFrameChannel fc is called at the start of the processing This is a good place to prepare the processing such as booking the histograms e Bool t ProcessCut FrameH frame is called for each frame If the result returned is FALSE the next steps of processing are ignored for this frame Bool t ProcessFrame FrameH frame is called for each frame and does the real processing e void Terminate is called at end of processing One can display histograms here for example Once the file selectorname C is customized it becomes the argument of VFrameChannel Process vega fc gt Process selectorname C 712345678 65 1300 this will interpret the file selectorname C and send it frames starting at GPS time 712345678 65 for a duration of 1300 s The last argument is an optional condition on the data One can also compile the script before processing 48 vega fc gt Process selectorname C will compile the file selectorname C load it and process all the data available to the frame channel through it When appending a single the file will be co
33. ame of the vector containing the image is MYGO_IMAGE plot it vega gVM gt Draw fr MYGO_IMAGE col That s it The option col used for this drawing produces the third plot showed hereafter other options are shown 57 MYGO_IMAGE gt 100 MYGO_IMAGE No option scatter plot Option surf1 MYGO_IMAGE Option col Option surf4 The options available are the ones of the ROOT TH2 class and are summarized below SAME Superimpose on previous picture in the same pad CYL Use Cylindrical coordinates POL Use Polar coordinates SPH Use Spherical coordinates PSR Use PseudoRapidity Phi coordinates LEGO Draw a lego plot with hidden line removal LEGO 1 Draw a lego plot with hidden surface removal LEGO2 Draw a lego plot using colors to show the cell contents SURF Draw a surface plot with hidden line removal SURF1 Draw a surface plot with hidden surface removal SURF2 Draw a surface plot using colors to show the cell contents SURFS same as SURF with in addition a contour view drawn on the top SURF4 Draw a surface using Gouraud shading CONT Draw a contour plot same as CONTO CONTO Draw a contour plot using surface colors to distinguish contours CONT1 Draw a contour plot using line styles to distinguish contours CONT2 Draw a contour plot using the same line style for all contours C
34. by the available amount of memory gROOT gt Reset FrVect frv Double t time Max number of vectors displayed Int_t nvecmax 20 Time step of the scroll Double t tistep 1 Length of the displayed vector Double_t veclength 4 Open a new window canvas cl new TCanvas cl cl1 1 Open a frame channel vd new VFrameChannel demoDB root Start time time 400000000 1 Get the first vector frv vd gt GetVect adc MYGO ADC1 time veclength Int_t nvec 0 while frv 0 amp amp nvec lt nvecmax nvec printf nvect d time fn nvec time Draws the vector gVM gt Draw frv Update the canvas gPad gt Update FrvectFree frv time tistep frv vd gt GetVect adc MYGO ADC1 time veclength Get the next vector 82 XII 3 Example 3 histogramming some data and fitting the result This example shows how to use histogramming with the VManager Access is made to the data and an interesting part containing a peak is displayed as well as a histogram of the data The histogramed data is accumulated over several frames and at the last frame a fit is made to the histogram One fits a gaussian to show the deviation from gaussianity The example is in the macro scrol12 c This example plots a vector and accumulates a histogram of the values of this vector Only the part of the vector that corresponds to the interesting par
35. ccteostgenersiielaaeh dgusasnntecseehdueaaepnasisagdedesswesotes 14 IL Pr paration of th SCTIpP mienne inner er men ner riens 14 14 2 Compiling the Serpia ee naaa r diner ane re esse mme ntm nations 15 11 4 3 Compiling a more complex code 15 Hands on VEGA scscuccumenaussunenuaseumenuneennenenenennnnn LO Hi Preparation sue ne mere Tee d cide es ne eee its ere 16 11 22 Opening a Fram Channels ibn disant andre mme der arte etienne 16 IIS Extracting a frame using a frame channel and plotting it 17 II 4 Extracting a vector using a frame channel and plotting it 18 ITS Extracting a 2D vector image from the frame channel and plotting it 19 II 6 Building a metadatabase for more complex tasks cece ee cece eee eeeeee een eeaeeaees 19 Ill 7 Extracting a frame with a condition or Selection 20 II 8 How to deal with slow monitoring data oo cece cee ence eeaeeeeeeeeeeee sen eeaeeaeeaees 21 More on C for the interested reader mmmmmmmmnnnrs 2D IV 1 C notions used classes methods and constructors 25 IV 2 C notions used inheritance and data encapsulation cece cece e cece een eenees 26 IV 2 1 Inheritance aenn araa a LE EM Re re tant ded ne TT 26 IV 2 2 Method overriding s same bieneeler tente iinu etai e ten but 27 IV 2 3 Public and private data encapsulation ccc eee cece seeeeeeeeeeeeeeee
36. ch is the name of the canvas followed by _1 _2 etc for example to cd to the third pad you should do vega can_3 cd The third pad will set itself as the selected pad since you call the TPad cd method for the object can_3 This remark just to show the state of mind people have when they think in C 11 2 7 Inheritance and data encapsulation 1 2 7 1 Inheritance There is an obvious question that could be asked what is the relation between a canvas and a pad Isn t it almost the same thing Yes it is In fact a canvasisa pad that spans through an entire window This is nothing else than the notion of inheritance The TPad class is the parent of the TCanvas class So what The most interesting thing is that you can reuse the code written in the parent class For example cd is a method that TCanvas inherits from it s parent TPad 1 2 7 2 Method overriding The method overriding is explained in chapter IV Basically when a class Child derives from another class Parent it can reuse the methods defined in Parent but if one method of Parent is not well adapted to Child one can redefine override it For example Draw in some Child class may be different from Draw in the Parent class There is no ambiguity since you always specify the object childobject Draw or parentobject Draw 10 11 2 8 ROOT related specifics For what concerns inheritance most objects in ROOT derive from a base class called T
37. class like this class TLine int xl int yl int x2 int y2 TLine int x1 int yl int x2 int y2 void Draw where we added two functions that we will call methods or member functions to the TLine class The first method is used for initializing the line objects we would build It is called a constructor The second one is the Draw method itself So to build and draw a line we have to do TLine 1 0 2 0 2 0 8 0 9 1 Draw The first line builds the object 1 by calling its constructor The second line calls the Draw method of this object You don t need to pass any parameters to this method since it applies to the object 1 and knows what are the coordinates of the line These are internal variables x1 y1 x2 y2 that were initialized by the constructor 1V 2 C notions used inheritance and data encapsulation 1V 2 1 Inheritance There is an obvious question that could be asked what is the relation between a canvas and a pad Isn t it almost the same thing Yes it is In fact a canvasisa pad that spans through an entire window This is nothing else than the notion of inheritance The TPad class is the parent of the TCanvas class So what The most interesting thing is that you can reuse the code written in the parent class For example cd is a method that TCanvas inherits from it s parent TPad Let s try another example Wee defined a TLine class that contains everything necessary to draw a l
38. ct with the right information In this way the user always keeps control of creation deletion of the metadata objects Be careful while GetFrame is checking to see if the requested time is really contained in one of the frames of the database GetNextMeta and GetPreviousMeta do not They will simply return you the metadata that is the next or previous one in time in the database even if it s years away 1 1 4 Getting general information about the metadatabase and it s contents 1 1 4 1 Getting the start time of the metadatabase To get the start time of the first frame indexed in the metadatabase one has to use the VFrameMetaDB method double GetStart For example if vd is a valid metadatabase vega vd gt GetStart will output this start time while vega st vd gt GetStart will put it in a double that may be reused 1 1 4 2 Printing information about the metadatabase One can get some information about the metadatabase by using the VFrameMetaDB method double Print For example if vd is a valid metadatabase vega vd gt Print This will show a rather extensive output of the metadatabase content 1 2 Dealing with selected or triggered data 1 2 1 Condition information in the metadatabase When the metadatabase is build by reading the frame files the trigger information contained in each frame is retrieved and arranged in such a way to allow easy extraction of frames or vectors satisfying some selection
39. ctors We can have in the future a class named VManagerFramecpp that will use the frame class library Framecpp instead It is not important to understand what VManagerFrameL exactly does this will be explained in the next paragraph What do we want a general VManager to do Basically anything related to the interface between frames and VEGA A first tentative list that will soon get longer may be Drawing of vectors 1D and 2D series images Drawing of distributions of series data Management of the VSPlots produced Etc VII 2 2 Building a manager the global gVM In VEGA there is a global variable called gVM that is already declared as a VManagerFrameL and one can use it as he she wants gVM is the current VManager If one declares another manager gVM will point to it In practice you can just forget about building a manager and use the standard gVM provided If absolutely necessary one starts a manager by building a new object of a VManagerXXX class For example to start a manager using the FrameLib one does vmgr new VManagerFrameL VII 2 3 General use Once building is done which is by default already the case when you launch vega one has to call methods from the declared gVM object For example gVM gt Draw frame adc IFO DMRO will draw the data from the IFO DMRO adc contained in the frame frame which is a FrameH structure loaded with standard Framelib calls It will take care of creatin
40. d if it is 2D it produces a VSPlot2 The manager then handles two lists of produced plots one for 1D and one for 2D One can get a pointer to the last created and plotted VSPlot VSPlot GetLastPlot As in vega VSPlot vsl gVM gt GetLastPlot This could be useful if one wants to modify this VSPlot for example to change some attributes An example is given in the macro peak2 C One can also get a pointer to the last created and plotted VSPlot2 VSPlot GetLastPlot2 As in vega VSPlot2 vsl gVM gt GetLastPlot2 This could be useful if one wants to modify this VSPlot2 for example to change some attributes VII 3 Representing slow monitoring data There are three main powerful drawing methods for slow monitoring data i e VNtuples They all enable putting selections i e drawing data that pass given cuts The first method draws VSPlots which are standard representations of time series This method is mainly used to treat slow monitoring data as simple time series We encourage you to use this first method since it gives powerful manipulation signal analysis capabilities void DrawSeries Text_t varlist Test_t cuts Text_t option Int_t nentries 1000000000 Int_t firstentry 0 The parameters are almost identical to the ones of the second method and are described below The only difference is in the option parameter option is an option for drawing SAME Superimpo
41. d in each frame is gathered and arranged in such a way to allow easy extraction of frames or vectors satisfying some selection The triggers structures of type FrTrigData in the FrameLib are converted to more general objects called conditions This will allow to use in the future as conditions other information such as slow monitoring data or quality information The user may even add his own conditions without copying the whole files just to adda FrTrigData structure The reader may find as an example the structure of the VEGA metadatabase in Appendix A V 5 2 Condition Sets Condition sets class VConditionSet are objects designed to be used as iterators on the conditions gathered in info databases allowing a user to select a subset of all the conditions through a selection formula and to determine successively all the time intervals where this selection is valid In other words a condition set contains a selection expression on the conditions and is used as a pointer to the successive intervals of time satisfying this selection This will be clearer with an example Suppose two triggers were defined in a set of frames say Trigl and Trig2 These triggers have a given amplitude which may vary and we would like to select for example all time intervals for which Trigl amplitude gt 50 amp amp Trig2 amplitude gt 1 This is our selection expression A condition set will be build with this expression as for example in vega
42. d problems we decided to keep both So you can use Float_t ROOT type or REAL_4 Framelib type indifferently We know this can be misleading but one cannot avoid some historical background for Int t i 0 i lt 10000 i xgauss gRandom gt Gaus 3 0 5 h1 gt Fill xgauss 0 2 h1 gt Fill xgauss 6 This seems to be a standard for loop in C in which you generate a random variable gaussian and you fill a histogram with this value For somebody not used to C something is strange the Fill method used to fill the histogram is used twice but not with the same number of arguments This is perfectly common in C and it is called method overloading We will see more about this in the next paragraph Now to execute your macro type vega x vfill histo c Creating Histogram done Filling Histogram done Now you have in your memory the computer one not yours a histogram with which you can play For example type vega h1 gt Draw vega h1 gt Dump As will be seen in the chapter Writing macros one can write a named macro and give arguments to a macro You also probably noticed that there is no includes in the macro In fact all the standard C includes are already done in the environment as well as ROOT and VEGA specific ones 11 3 1 C notions used method overloading We ve just seen in the example above that a method can have different forms with different arguments If we look at an e
43. drawn line or plot with the third mouse button have a popup menu and select methods like we did for histograms The interactive zoom is also available It is also possible to plot images coming from cameras that are included in a frame as FrVects in 2 dimensions One uses the same syntax as for 1D the manager gVM will take care of producing the right plot The tutorials contain a few examples of the use of gVM see the macros scroll2 C and peak2 C for example 11 4 Extracting a vector using a frame channel and plotting it What if you don t want to take care of frame boundaries just want to see a vector containing MYGO_ADC1 data beginning at the time 400000023 and lasting 10 seconds The frame channel can do that Do vega ve w gt GetVect MYGO_ADC1 400000023 10 vega gVM gt Draw ve The first line extracts the vector the second draws it Notice that you didn t care about the frame boundaries one of which is around 400000024 5 the other around 400000030 Of course one can extract a vector as big or as small as he wants limited by the available machine memory of course One note the user should take care of freeing the memory for all Framelib objects that are returned Once a FrVect or a FrameH is extracted it is the user s responsibility to free memory in his loops with FrameFree fr and FrVectFree ve In a future version we will try to do an automatic garbage collection to free the user from these
44. e the second at a time relative to the reference time see chapter Dealing with time condset is a condition set defined as explained in the paragraph Condition Sets Example vega frame fc gt GetNextFrame condset The search will be governed by the condition set condset The frame returned will be the one containing the start time of the next interval pointed to by condset These methods have to be called sequentially in a loop This method sends back a pointer to a well known FrameH structure One warning the memory for returned frames is allocated by the system but it is the user s duty to free it after use One has to do vega FrameFree frame after finishing using the frame object V 5 4 Extracting vectors with a condition Instead of extracting full frames it is possible to extract only some vectors The start time and length of the condition time interval will direct the start time and length of the vectors The user does not yet control the length of the vector returned As for frames the extraction may be direct or sequential V 5 4 1 Direct methods The methods of VFrameChannel that allow a direct conditioned access to vectors are FrVect GetNextVect Text_t nameofvect Double t gpstime char selection FrVect GetNextVectR Text_t nameofvect Double t gpstime char selection They return a vector of type FrVect given its name and type The vector spans a time interval for which the c
45. e of the habits of many people Since people are used to the C version and since at the moment the C version is not quite ready we preferred to use a manager class that is taking the Framelib objects and building graphical objects with them This class is called VManagerFrameL At initialization time a global variable of type VManagerFrameL is build called gVM and it is available for all kinds of management tasks taking care of drawn plots freeing memory when necessary taking care of a reference time etc So the last command we did created a plot graphical representation class VSPlot of the frame fr content more specifically of the adc channel named MYGO_ADC1 The adc characters may be omitted if there is only one vector adc proc or sim with that name Even if it is supposed to be only a graphical representation of a vector a VSPlot is much more than that In fact it contains almost all the information contained in a time series FrVect for example It can be the starting object for a truly OO way of doing time series For the moment let s access the VSPlot object that was created vega vsp gVM gt GetLastPlot It was said that the VManager called gVM takes care of all the drawn plots This instructs gVM to return us a pointer to the last drawn plot Now we can do things like vega vsp gt SetLineColor 4 You can always use lt Tab gt to see the available methods Furthermore one can click on the
46. e on time series axis 69 IX The Data Display as a data Viewer mmmmmmmmnmnnnnnnns 7 3 EXT GOAaIS wy ses sen ner renard ere sde O ne dede ete 73 XI XII XIII IX 2 1 Displaying data from a frame channel source 73 IX 2 2 Interaction with the produced plots 73 IX 2 3 Using configuration files produced by the standalone dataDisplay application 74 Signal processing and algorithms mmmmmmmnnmnnmnnmnnnnnnnus D The global variables often uSsed msmmmmmmmnnennnunnnnennnnne 7 7 XI The active manager 2V Migs ee Meare erage ne de An eee aes 77 X2 Theractive style pVStyl s nr nn avg a AKE o nn sae duane ese eds ae dita dent cena st seed 77 Examples Of macroS mmmmmmmmmnmmnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne 79 XII 1 Example 1 Displaying a peak sise 79 XIL2 Example 2 z scrolling datarn cco ies ance Pate vigal neds dan anna er ee eee 81 XIL3 Example 3 histogramming some data and fitting the result 82 XIL 4 Example 4 Extracting some slow monitoring data and doing some simple plots 84 XILS Example 5 Extracting a vector and plotting spectra 86 How to compile your own code for VEGA or use the VEGA libraries in your COde nmmmsmmnnmmmennennnnnnnannnnnnnnnnnnnnnnnnnnn 09 XIIL 1 Loading an existing shared library
47. eans that every name declared public is seen by the outside world This is opposed to private which means only the class where the name was declared private could see this name For example suppose we declare in TArrow the variable ArrowHeadSize private as in private int ArrowHeadSize Then only the methods member functions of TArrow will be able to access this variable Nobody else will see it Even the classes that we could derive from TArrow will not see it On the other hand if we declare the method Draw as public everybody will be able to see it and use it You see that the character public or private doesn t depend of the type of argument It can be a data member a member function or even a class For example in the case of TArrow the base class TLine is declared as public class TArrow public TLine This means that all methods of TArrow will be able to access all methods of TLine but this will be also true for anybody in the outside world Of course this is true provided that TLine accepts the outside world to see its methods data members If something is declared private in TLine nobody will see it not even TArrow members even if TLine is declared as a public base class What if TLine is declared private instead of public Well it will behave like any other name declared private in TArrow only the data members and methods of TArrow will be able to access TLine it s methods and data members nobod
48. ectors is allocated by the system but it is the user s duty to free it after use One has to do vega FrVectFree vect after finishing using the vector object V 5 5 Getting information about condition sets V 5 5 1 Printing the names of the conditions present in an information database When printing information about a frame channel the dump of the first frame is made But this doesn t show all the conditions that exist in the connected database To show the names of all the conditions gathered when building the info database one has to use again the Print method of VFrameChannel but with an option conditions For example if fc is a valid frame channel vega fc gt Print conditions will do it V 5 5 2 Current status of a condition set A condition set as explained above points to a particular section of data satisfying some criteria It may be useful to get some information about the current status of a particular condition set The following methods of VConditionSet are used to retrieve this information double GetIntersectionStart double GetIntersectionEnd Returns the start and end time of the current region of interest This region is the intersection region of all the conditions that compose the condition set Example provided cs is a valid condition set vega cs gt GetIntersectionStart double 661234567 1 vega cs gt GetIntersectionEnd double 661234569 3 double GetLastConditionRes
49. ectrum C in the tutorials More information will be added as soon as the Frv library gets a standard shape 76 XI The global variables often used D a XI 1 The active manager gVM XI 2 The active style gVStyle 78 79 XII Examples of macros The examples are available interactively in the VEGA site tutorials We suppose you have created the demo frame files by executing the macros create_testfr C and the corresponding local metadatabase with create_DB C this is just a two lines script that does what is described above for creating a database XII 14 Example 1 Displaying a peak The first example is showing how one can display a potentially interesting peak zooming in and plotting two channels on top of each other macro peak C This example shows how to plot a region of interest To see the result of this macro click here The access of data is made by its time A much fancier example is given in here gROOT gt Reset Open a new window canvas cl new TCanvas cl1 A peak example 1 Creates the needed pads by dividing the initial canvas cl gt Divide 2 2 Opens the frame channel vd new VFrameChannel demoDB root Gets the needed vectors and draws them First the upper plots FrVect frvl vd gt GetVect adc MYGO ADC1 400000010 3 FrVect frvSeis vd gt GetVect adc MYGO Seis 400000010 3 cl
50. ent directory Even more if you write vega w new VFrameChannel lt tab gt You will have the list of variables used by this method with the default parameters and all the possible versions This is VERY helpful One last word Using a frame channel connected directly to files should be done only if frames are sequentially ordered in the files and not mixed inside several files If the case is more complex one should build a metadatabase and connect the frame channel to it This is described later on Hi 3 Extracting a frame using a frame channel and plotting it Now as advertised you can extract a frame from the set of files with vega fr w gt GetFrame 400000023 To see the contents of the frame one can do the standard Framelib call vega FrameDump fr stdout 2 Which gives a summary of the contents of the frame One can see that there is an ADC channel named MYGO_ADC1 But you can have the same kind of information from the framechannel itself by issuing vega w gt Print This will print all kinds of information about the framechannel and dump the contents of the first frame To draw the previously extracted frame in the current pad just do vega gVM gt Draw fr adc MYGO_ADC1 Woaw what is this new beast gVM Well if we wanted to be consistent with the Object Oriented way used in ROOT we would have needed to use a fully C version of the Framelib But this would have meant a complete chang
51. eofntuple Text_t varlist Double t start Double_t length VNtuple ExtractSMSR Text_t nameofntuple Text_t varlist Double t start Double_t length The first method extracts an SMS at an absolute time the second at a time relative to the reference time see chapter Dealing with time nameofntuple is the name of the new ntuple to be built varlist is the list of variables to extract Colons separate the variables and each variable name is constructed with the name of the slow monitoring station followed by the name of the variable separated by a dot like stationname varname So TiServer TA1 TiServer T2 To9Tp G41 is a valid variables list If one wants to extract all the variables of a station just give the name of the station without any variable TiServer To9Tp will work of course if these stations exist start is the time from which the extraction starts in the database It is an absolute GPS time for the ExtractSMS method and a time relative to the reference time for ExtractSMSR length is the length of the extraction section in seconds The variables and slow monitoring stations are checked for in the first frame accessible after the time start If the variable names were given the search will be made until the end of the searching section till the time start length is reached But if all the variables of a station were asked for and this station is not present the ntuple will not be build
52. et of parameters This is one example of a function associated to a class It is a special one since it builds an object It is called a constructor To interact with an object in ROOT the usual syntax is object action parameters This is the usual way of doing in C The dot can be replaced by gt if object is a pointer But since the interpreter always knows the type class of an object if you put a dot instead it will be automatically replaced when necessary So now we understand the two lines that allowed us to draw our function 1 Draw means call the method Draw associated with the object f1 of class TF1 We will see the advantages of using objects and classes very soon One point the ROOT framework was designed as an object oriented framework This doesn t mean that a user cannot call plain functions For example all the FrameLib standard functions are available in the VEGA framework 11 2 4 ROOT related specifics We didn t yet explain everything about the constructor of f1 TF1 1 funcl sin x x 0 10 sin x x is the function that we want to define O and 10 the limits but what is funcl It s the name that we give to the object f1 Most objects in ROOT have a name That way there are lists of objects maintained by ROOT and it s easy to find an object by its name especially if it is in a database We will see why it is so when we see the notion of inheritance 1 2 5 Graphical outpu
53. ew TCanvas can Test canvas 1 vega can Divide 2 2 Once again we called the constructor of a class this time the class TCanvas The difference with the previous constructor call is that we want to build an object with a pointer to it In C we would have used malloc or calloc Here we use the operator new which is the equivalent in C Instead of free we will use delete Usually one has to declare a variable before using it Since there cannot be any ambiguity in the line above one doesn t need to declare a variable can In case such a statement in a macro is intended to be compiled one would obviously have to declare the variable as a TCanvas before using it Next we call the method Divide of the TCanvas class that is TCanvcas Divide which divides the canvas into 4 zones and sets up a Pad in each of them Now if we do vega can cd 1 vega fl Draw the function f1 will be drawn in the first Pad All subsequent actions draw an arrow for example will be done on that Pad To change the working Pad there are three ways e Click on the middle button of the mouse on an object for example a Pad This sets this pad as the active one e Use the method cd of TCanvas that is TCanvas cd by telling the number of the pad as was done in the example above vega can cd 3 Pads are numbered from left to right and from top to bottom e Each new pad created by the TCanvas Divide method has a name whi
54. example the file my_test C should begin with my test your code The tutorial script called scrollspectrum c has been prepared this way check it XIII 2 2 Compiling the script What remains to be done is to compile the script If we want to execute the script called scrollspectrum C we just have to do once in the vegatutorial directory vega x scrollspectrum C notice the at the end of the command This tells the interpreter to compile scrollspectrum cC build a shared library called scrollspectrum so load this shared lib and execute scrollspectrum The resulting library scrollspectrum so stays here and you can reuse it that is reload it at a later time with vega L scrollspectrum so furthermore the scrollspectrum function is available in the interpreter and may be used in some other script All this also works with loading the script after compiling vega L scrollspectrum C is a valid statement This will build the library and load it as before It will just not execute any function XIII 2 3 Limitations The script compiler is not intended to be used for big projects Do not expect to compile libraries that are made of many subroutines in many different source files It is quite efficient though for checking that a code will compile before effectively using it It is also possible to overcome some CINT limitations using the script compiler since it uses the full featured compiler you are u
55. ext_t option Int t nentries 1000000000 Int _t firstentry 0 varlist is an expression of the general form e1 e2 where el etc is a formula referencing a combination of the ntuple columns Example varexp x y simplest case draw a plot of points x y x and y representing columns named x and y t sqrt x draw plot of sqrt x vs t log t x y z Note that the variables el or e2 may contain a selection example if e1 x y lt 0 the value plotted will be x if y lt O and will be O otherwise cuts is a selection expression Only ntuple entries passing this selection will enter into the graph For example it could be something like t gt 10 amp amp sin TP1 6 28 lt 0 One can use standard C operators amp amp and usual mathematical functions including transcendental ones option is an option for drawing The available options are option A Axis are drawn around the graph option T Time is used for axis labels not a standard graph feature added by VEGA option P The current marker is drawn at each point option L A simple polyline between all the points is drawn option F A fill area is drawn CF draw a smooth fill area option C A smooth Curve is drawn option A Star is plotted at each point option B A Bar chart is drawn at each point Options should be combined to obtain the desired effect Typically the first graph i
56. f a vector contained in a frame void DrawHist FrameH frame Text_t typeAndName Float_t offset 1e20 Float_t dur 1e20 const Text_t hwork Option_t option Makes a distribution of the values contained in a vector of type FrXXXData XXX Adc Proc or Sim contained in the frame frame and of type and name typeAndName This method generates or uses a histogram of the class THIF If the histogram is generated its limits are determined automatically to be 5 of the max and min value in the series and this histogram has 100 bins The variables are frame is a frame of type FrameH that has been read from a file typeAndName is a pointer to an array of char that describes the type adc proc or sim and name of the frame element to be extracted and drawn It has the following structure type name For example adc IFO_DMRO is a good format It will look for the adc data of the adc named IFO_DMRO It is possible to give only the name if there is no ambiguity In that case adc data will be searched first for that name then proc and then sim data If more than one identical name was used the first found series will be extracted offset is the offset from which the histogramming starts with respect to the 55 starting value of the series dur is the length of the histogramed part of the series hwork is optionally the name of an existing histogram for example histo1 This allows using any limits for the
57. files one wants to open as in vega fc new VFrameChannel file demo400000000 F demo400000045 F The commands and functions to extract a frame or a vector are from then on the same as in the following cases V 3 2 More complex case metadatabase When the set of files becomes big or the frames are scattered in non sequential order in a set of files or one wants to use conditions or triggers it is necessary to build a metadatabase that will keep the information about frames location and characteristics It will be used as an index to access the real frames One builds such a metadatabase with for example vega vd new VFrameMetaDB demoDB root CREATE demo The first argument of the constructor for a metadatabase is the name of the ROOT file that will contain metadata in our case demoDB root next the mode of opening READ by default but we used CREATE to build a new database The third argument is the path to the files As can be seen one can use wildcards to specify frame files names But one could as well specify a directory name The search is by default recursive which means you can set the beginning of the search to the top of a directory tree containing directories etc The metadatabase structure and methods are described in Appendix A When a metadatabase is build one should connect a frame channel to it vega w new VFrameChannel demoDB root The prefix metadb may be put in front of
58. first function of the script you compile you have to name the function in your script with the same name as the file it is contained in For example the file my_test C should begin with my test your code The tutorial script called scrollspectrum c has been prepared this way check it 11 4 2 Compiling the script What remains to be done is to compile the script If we want to execute the script called scrollspectrum C we just have to do once in the vegatutorial directory vega x scrollspectrum C notice the at the end of the command This tells the interpreter to compile scrollspectrum C build a shared library called scrollspectrum so load this shared lib and execute scrollspectrum The resulting library scrollspectrum so stays here and you can reuse it that is reload it at a later time with vega L scrollspectrum so furthermore the scrollspectrum function is available in the interpreter and may be used in some other script All this also works with loading the script after compiling vega L scrollspectrum C is a valid statement This will build the library and load it as before It will just not execute any function 11 4 3 Compiling a more complex code You will probably at one point or another try to compile a more complex code consisting of a few files or you will want to use the VEGA capabilities in your own code for example use the display of vectors in a standalone executable
59. frv FrVectFree frv delete vd 88 XIII How to compile your own code for VEGA or use the VEGA libraries in your code XI11 1 Loading an existing shared library If a shared library that was suitably prepared we will see what that means exists already it is possible to extend VEGA by loading it The command to do that is L as in vega L scrollspectrum so Once this has been done the functions and methods that are defined in the library are available at your fingertips in the interpreter What means suitably prepared is that one has to build the stub functions that make the interface between the interpreter and the real functions This is however an automatic process that is using a tool called rootcint We will describe it more extensively later XIII 2 Compiling a script and making a shared library of it The script compiler was introduced in the chapter How to compile a macro Before going further let s remind what was said Sometimes in fact quite often a script may become so big or be so processing hungry that one would like to have it compiled and not interpreted There is included into ROOT what is called a script compiler that allows compiling very easily the scripts you are going to produce It starts by calling the C compiler that was used to build ROOT and builds a shared library This shared library is then loaded and the function defined in the script is executed The shared
60. g a VSPlot or a VSPlot2 depending on the dimension of the vector We are going in the next paragraphs to concentrate on the manager that uses the Framelib Almost the same routines will be available if another C based frame manager software is written and interfaced with VEGA VII 2 4 Drawing methods VII 2 4 1 Drawing contents and distribution of frame vectors The drawing methods of the VmanagerFrameL class are the following They can be used with statements like gVM gt XXXX Where XXXX is the methods name void Draw FrVect vect Float_t offset Float_t dur le20 Option t option Will do a drawing of a vector output on the screen is a VSPlot or VSPlot2 where vect is a frame vector of type FrVect that has been extracted from a frame offset is the offset from which the drawing starts with respect to the starting value of the vector i e series dur is the length of the drawn part of the vector i e series option is an option string that is passed to the plot that is drawn This is equivalent to the TH1 class drawing options except for one addition The reader can go to the address http root cern ch to see the list of options in the drawing of a TH1 see Classes and Members Reference Guide The added option is sameti option If offset and dur are omitted the whole vector is drawn It is also possible to specify only the drawing option A VSPlot is drawn in the current pad or canvas The addre
61. gauss gRandom gt Gaus 3 0 5 h1 gt Fill xgauss 0 2 h1 gt Fill xgauss 6 printf done n We can try to give detailed explanations of some of the lines above gROOT gt Reset This statement resets the interpreter environment it is almost always used at the beginning of a macro but not if you want to preserve some variables that a precedent macro defined gROOT is a global variable We will see some more details about globals in ROOT in a few moments gROOT is an object of the class TROOT which represents your session It contains among other things lists of named objects created during the session such as histograms This enables access to those objects by their name THIF hl new THIF h1 1 D Gaussians 100 8 8 Here we create a histogram by invoking one of its constructors Walking through this statement we have THIF this is one of the histogram classes All ROOT classes begin with a T see Coding Conventions As we will see all VEGA classes begin with a V H is for histogram 1 for 1 D and F for using one float per channel hl is the name of the pointer to this object new TH1F invokes the constructor for this object with several parameters gt hl is the name of the histogram In ROOT as we have seen most high level objects are named Typically one makes the name of the object the same as the pointer to which it refers gt 1 D Gaussians is the title of the hist
62. getting information about file location in the information database extracting the data from the frame files and providing the result to the user This is shown in the following picture 32 Frame files real data Frame Channel Frame file information User metadata Except when building a metadatabase the user interacts mainly with the frame channel to get the data in the form of frames or vectors The frame channel will interact with the information database through the exchange of metadata while accessing directly the frame files Clearly this scheme is extendable to any kind of information or metadata and any type of frame location even remote V 3 Different information databases for different uses There are various types of information databases that are foreseen Depending on the complexity of frame information the user may want to choose one or the other V 3 1 Simple access direct files If one has a few files containing frames ordered sequentially there is no need to build a database One could think of accessing them with direct FrameLib calls This is certainly doable It may be convenient though to have exactly the same calling sequences than for more complex cases One can think to build metadata on the fly with the information contained in the files themselves So when building and opening a frame channel there is a direct files mode which is defined by adding the prefix file to the name of the
63. ghout the whole world But the inconvenience is for everyday use that GPS times are expressed as seconds since 1980 January 5 24 00 00 That means 9 digits numbers This may be very cumbersome So there is a need for a convenient way of expressing time while working This problem arises in two different fields when one wants to access data and when one tries to output information related to time VIII Time when accessing data When trying to access data it would be nice if one could say I want to access a frame or vector that began 10 minutes ago or Give me the vector beginning the 14th of July 2001 at 14 34 05 instead of time 632145148 VIII 1 1 The reference time This is why in VEGA one can access data with respect to a reference time This reference time is local to a frame channel To access data one can use two types of methods The standard ones which work in an absolute way i e you have to give the absolute GPS time like VFrameChannel GetVect and the ones that work by reference to a given time They differ from the first ones only by the fact that there is an R at the end of the methods name For instance VFrameChannel GetVectR The arguments are the same except that the time is expressed as the number of seconds since the reference time It may be negative to define a time that was before the reference one See the chapter on data access for more information VilI 1 2 How to set a reference time Si
64. gram but only with the values in its range So one can concentrate on the distribution of values around 0 Since no type adc proc or sim was given it will search for the first data occurring with this name in the frame gVM gt DrawHist frame MYGO_ADC 0 2 0 4 h1 This will do the same thing as before but without erasing the values of the histogram before filling It will just add those to the existing ones That way one can span more than one series for one given histogram VII 2 4 3 Drawing 2D vectors images or time frequency plots Frame vectors may contain bi dimensional information such as images coming from cameras or time frequency plots There is no special method for drawing these 2D plots One uses gVM gt Draw methods as for 1D and these methods take care of producing the right plot 1D or 2D depending on the dimension of the data In the case of 2D the plot produced is of type VSPlot2 The manager handles a list of these plots as well as a list of 1D plots Example In the files produced by the create_testfr C script in the vegatutorial directory some frames contain images They are generated as a sum of two dimensional functions and are there only for demonstration purposes Once in vegatutorial the following lines should show an image first open a database vega vd new VFrDataBase demoDB root second extract the first frame of this database vega fr vd gt GetNextFrame third since the n
65. he number and size of those files But typically it consists of a sequential read of all the files This shouldn t be much slower than the speed of the connection to the disk containing the directories 1 1 3 Access to metadata 1 1 3 1 Opening an existing database Opening an existing metadatabase may be done by using the constructor in READ mode which is the default vega vd new VFrameMetaDB demoDB root One may replace demoDB root with the path name of his local database 1 1 3 2 Extracting metadata Metadata are extracted from the database with void GetMetaData VMetaData meta Double t time This method extracts a metadata at an absolute time As in vega vd gt GetMetaData meta time where time is a double expressing a time that is contained in the frame and meta is a pointer to a VMetaData metadatabase object created by the user to be filled This method fills the meta object with the right information In this way the user always keeps control of creation deletion of the metadata objects Once one has extracted one metadata it is possible to extract the next one or the preceding one in the database GetNextMeta VMetaData meta For example vega vd gt GetNextMeta meta or GetPreviousMeta VMetaData meta For example vega vd gt GetPreviousMeta meta where meta is a pointer to a VMetaData metadatabase object created by the user to be filled This method fills the meta obje
66. he vector is arbitrary and is only limited by the available amount of memory It is also shown how to use the FFT from the signal analysis library gROOT gt Reset gBenchmark gt Start scrollspectrum FrVect frv Max number of vectors displayed Int_t nvecmax 20 Time step of the scroll Double t tistep 1 Length of the displayed vector Double t veclength 4 Start time Double t time 400000000 1 Open a new window canvas and split it cl new TCanvas cl cl1 1 ci gt Divide 1 2 cl gt cd 2 Open a frame channel vd new VFrameChannel demoDB root Get the first vector frv vd gt GetVect adc MYGO ADC1 time veclength Int_t nvec 0 while frv 0 amp amp nvec lt nvecmax nvec printf nvect d time f n nvec time Draws the vector in the first pad cl gt cd 1 go to the first pad gVM gt Draw frv Calculates the spectrum FrvRFFT fft fft FrvRFFTFor 0 frv Draws the spectrum in the second pad cl gt cd 2 go to the second pad gVM gt Draw fft gt amplitude gPad gt SetLogx 1 gPad gt SetLogy 1 Update the canvas cl gt cd gPad gt Update Release the various variables allocated FrVectFree frv FrvRFFTFree fft time tistep 87 frv vd gt GetVect adc MYGO ADC1 time veclength Get the next vector gBenchmark gt Show scrollspectrum Do some garbage collection if
67. histogram provided the user defines one before calling DrawHist The contents of the histogram are erased before filling by the new values except if a precedes the name as in histol In this case the data is appended to the histo If the name hwork is given but there is no already existing histogram of that name a new one is created with standard characteristics option is an option string that is passed to the drawn histogram of type TH1F For the time being this is equivalent to the TH1 class drawing options The reader can go to the address http root cern ch to see the list of options in the drawing of a TH1 see Classes and Members Reference Guide Examples Let s assume that a FrAdcData vector contains data starting at t O and has a duration of 1 s with 50000 samples The min value is 123 the max value is 212 in a frame called frame gVM gt DrawHist frame adc MYGO_ADC 0 2 0 4 will draw the histogram of the values in the adc MYGO_ADC beginning at t 0 2 s for a duration of 0 4 s The generated histogram has limits 130 223 Example of such a plot cl ioj x File Edit View Options Inspect Classes Help htemp Nent 2000 Mean 1320 3 RMS 759 098 500 1000 1500 2000 2500 3000 hl new THIF h1 test histo 100 25 25 gVM gt DrawHist frame MYGO_ADC 0 2 0 4 h1l will generate the histogram h1 with limits 25 25 Calling the DrawHist method will fill this histo
68. hods because in the case of Trees the objects to be returned may be very complex and 46 one can try to get only a subset of these objects The GetEntries method returns the number of entries in the ntuple A simple loop to process all the values of a ntuple would be while int i 0 i lt vnt gt GetEntries i vnt gt GetEntry i float x vnt gt GetArgs printf nvar d xO fn nvar x 0 Of course one can do any kind of treatment in the loop If it s just a matter of printing the values the Scan method may be used The previous example could be replaced by a simple vnt gt Scan call V 6 3 Drawing The drawing methods are described in Representing gravitational wave data VI Analysis of data coming from a frame channel the selector It is possible to analyze data coming from a frame channel by retrieving it sequentially or randomly In this case it is the user s responsibility to do the analysis loop It may be interesting to automate the loop in order to let the user focus on the physics analysis and in order to prepare for parallel processing This is done by using the frame channel VFrameChannel Process method which sends a restricted set of data from a frame channel to a processing script or class written by the user called a selector Before we can process data we need to make this selector Generation of a standard source skeleton if fc is a valid frame channel is m
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70. ill be filled by information from the one containing the start time of the first interval satisfying the selection expression This method fills the meta object with the right information In this way the user always keeps control of creation deletion of the metadata objects 1 2 2 2 Sequential methods In order to access sequentially all the metadata of interest satisfying a selection expression one has to have an object that will point to the intervals of interest So came the idea of condition sets Once a condition set has been defined one can use it to extract metadata that are recorded at the corresponding time The methods of VFrameMetaDB to do so are GetNextMeta VMetaData meta VConditionSet condset This method extracts a metadata at an absolute time condset is a condition set defined as explained in the paragraph Condition Sets Example vega vd gt GetNextMeta meta condset The search will be governed by the condition set condset The metadata returned will be the one containing the start time of the next interval pointed to by condset 101 These methods have to be called sequentially in a loop This method fills the meta object with the right information In this way the user always keeps control of creation deletion of the metadata objects Table of Contents IV Introductioh s sssrcsecsusnesecentueseceuanesetcennssnceusnesauesauececesencese I 1 Whatis ROOT Presents Sunt a e aa aa T a NE
71. in information about file location triggers quality words etc and that will be used by the frame channel as an index to access data The details will be explained later but we can already build such a metadatabase for the tutorial files that we generated vega vd new VFrameMetaDB demoDB root CREATE demo The first argument of the constructor for a metadatabase is the name of the ROOT file that will contain metadata in our case demoDB root next the mode of opening READ by default but we used CREATE to build a new database The third argument is the path to the files As can be seen one can use wildcards to specify frame files names But one could as well specify a directory name The search is by default recursive which means you can set the beginning of the search to the top of a directory tree containing directories etc Now we can try to connect a frame channel to an existing database vega w new VFrameChannel demoDB root The instructions to extract a frame or vector are the same as in the direct file access case The only difference is that one is assured not to have any problems in case frames are mixed in various files or one wants to use a selected triggered set of frames 1 7 Extracting a frame with a condition or selection Frames are generally build with a certain set of conditions or selection parameters coming from the online triggers or decided by the user user may want to pr
72. ine If we want to draw an arrow is it so different from drawing a line We just have to draw a triangle at one end It would be very inefficient to define the class TArrow from scratch Fortunately inheritance allows a class to be defined from an existing class We would write something like class TArrow public TLine int ArrowHeadSize void Draw void SetArrowSize int arrowsize The keyword public will be explained later The class TArrow now contains everything that the class TLine does and a couple of things more the size of the arrowhead and a function that can change it The Draw method of TArrow will draw the head and call the draw method of TLine We just have to write the code for drawing the head IV 2 2 Method overriding Giving the same name to a method remember method member function of a class in the child class TArrow as in the parent TLine doesn t give any problem This is called overriding a method Draw in TArrow overrides Draw in TLine There is no possible ambiguity since when one calls the Draw method this applies to an object which type is known Suppose we have an object 1 of type TLine and an object a of type TArrow When you want to draw the line you do 1 Draw so Draw from TLine is called If you do a Draw Draw from TArrow is called and the arrow a is drawn IV 2 3 Public and private data encapsulation We have seen previously the keyword public This keyword m
73. integrated into VEGA This means that all the usual functions are accessible to the command line and in the macros For example you can try to run the macro vframel_ex C We let you compare it with the example FrameFull c of the Framelib manual There is a way to draw the time series vectors extracted from frames and this is described in the chapter Representing gravitational wave data V 2 General scheme for data access In a GW detection experiment we will certainly end up analyzing BIG amounts of data Even if the format of these data is determined the data itself will consist of many hundreds of files each consisting of many megabytes This is true even in local data that a user may want to analyze on his machine Furthermore when somebody uses some files locally chances are that those files contain frames that are not contiguous consisting of chunks of interesting data scattered through all the time the experiment was running How then access this data by time Or by frame run number The fundamental idea is to separate the files containing real data and the metadata or data about data containing information about frame file location beginning and end times conditions and triggers etc We will call the place where this metadata is stored an information database may take various forms as a metadatabase a bookkeeping database or the frame files themselves A mechanism called frame channel will act as a data provider
74. is no need to put a semicolon at the end of a line Well you can put one if you want This is only true for statements written on the command line One assumes that the carriage return is enough to express the end of the line for the interpreter This is part of the interpreter s extensions to C that were made to allow an easy interaction while not at the expense of breaking the compatibility with C C language Some of the extensions don t work anymore inside a macro For example you have to put a semicolon at the end of each line in a macro 1 2 2 Graphical output example Let s try something more interesting Again start VEGA your _prompt vega vega TF1 f1 funcl sin x x 0 10 vega 1 Draw you should see something like this Fe cl L of gt File Edit View Options Inspect Classes Help o 11 2 3 Classes methods and constructors We can stop for a second well a few seconds and explain what we have done A more thorough introduction to C is given in More on C for the interested reader chapter In ROOT and C we introduce the notion of object which is just a C structure with some internal functions called methods associated to it The line TF1 1 funcl sin x x 0 10 created an object named f1 of the type TF1 which is a one dimensional function The type of an object is also called a class In fact the line above builds an object by giving it a s
75. is turned on as in 71 vega gVStyle gt SetTimeOnXAxis 1l The other available option are gVStyle gt SetTimeFormat a user format Again see preceding paragraphs for the format Remember use the style global gVStyle BEFORE drawing the plot 72 IX The Data Display as a data viewer IX 1 Goals The Data Display is commonly used inside the VIRGO collaboration for interactive viewing of frames online via the network or offline in files The display is done inside a ROOT canvas so it was natural to incorporate the Data Display functionalities inside VEGA A user is then able to view some data then process the graphical result via a script For a detailed explanation of the Data Display use the reader is invited to look at the Data Display user s manual We will focus here on the interaction with VEGA IX 2 The Data Display inside VEGA Displaying data interactively using the Data Display may be done inside VEGA in two ways use the command dataDisplay vega dataDisplay This will launch the usual Data Display launch the data display on a frame channel previously opened DC 2 1 Displaying data from a frame channel source The frame channel is the main data providing mean in the VEGA philosophy It is thus natural to be able to view data coming from a frame channel inside the Data Display If fc is an already opened frame channel this is done by the command vega fc gt StartViewer
76. library that is produced is going to stay and you will be able to extend VEGA by loading this library later But before using the script compiler one has to prepare a little bit his script though it is quite simple XIII 2 1 Preparation of the script 1 2 3 You have to Do not use extensions to C C provided by the CINT interpreter That means for example that while in the interpreter you do not need to declare variables whose type is known from the context this is mandatory if you want to be able to compile Since the compiler is not supposed to know the context of the interpreter An example In the interpreter you can use statements like cl new TCanvas cl Test 1 where you do not declare the variable c1 you should do instead TCanvas cl new TCanvas cl Test 1 More generally use very standard C C and declare all your variables You should add the includes you use at the beginning of the file Once again this is for the real compiler that will do the work Usually the headers to be added are composed of the name of the classes used followed by the h suffix In case of included C code the most commonly used are FrameL h for all the Framelib calls and the standard headers of the Virgo standard signal library In case you want to execute immediately the first function of the script you compile you have to name the function in your script with the same name as the file it is contained in For
77. lly all the frames that correspond to a given selection expression V 5 3 1 Direct methods The methods of VFrameChannel that allow a direct conditioned access to frames are FrameH GetNextFrame Double t time char selection FrameH GetNextFrameR Double t relativetime char selection The first method extracts a frame at an absolute time the second at a time relative to the reference time see chapter Dealing with time selection is a selection expression referring to conditions existing in the database hence the frames such as Trigl amp gt 50 amp amp Trig2 amp gt 2 Example vega frame fc gt GetNextFrame time Trigl amp gt 50 amp amp Trig2 amp gt 2 the search will begin from time time The frame returned will be the one containing the start time of the first interval satisfying the selection expression This method sends back a pointer to a well known FrameH structure V 5 3 2 Sequential methods In order to access sequentially all the frames of interest satisfying a selection expression one has to have an object that will point to the intervals of interest So came the idea of condition sets Once a condition set has been defined one can use it to extract frames that are recorded at the corresponding time The methods of VFrameChannel to do so are FrameH GetNextFrame VConditionSet condset FrameH GetNextFrameR VConditionSet condset The first method extracts a frame at an absolute tim
78. mpiled and loaded but subsequent compilations will only be done if the file has changed since the last compilation VII Representing Gravitational Waves data Vil 1 Series plots Since the user may want to use the Framelib to access the frames and since there are many structures defining time series that can be used there is a need fora class or set of classes defining a representation of a time series or spectral series There are two such classes VSPlot for 1 dimensional plots and VSPlot2 for 2D The class VSPlot is the graphical representation of a series For the time being VSPlot derives from TH1D histogram class and adds some minor methods The drawing of VSPlot produces time series specific information such as the duration mean value etc written in a statistical box As we will see VSPlots are generally created and managed by graphical managers called VManagers A VManager holds a potentially big number of plots and takes care of their deletion if necessary One can refer to examples in macros peak C and peak2 C VII2 Graphical managers of frames VII 2 1 Definition of managers The manager classes are the heart of the graphical part of the VEGA environment They make the interface between the objects and libraries used by GW experiments such as the framelib frames and vectors and the ROOT framework VManagerFrameL is a class describing a manager that uses the Framelib for all its input output of frames ve
79. nally the name of an existing histogram for example histo1 This allows using any limits for the histogram provided the user defines one before calling DrawHist The contents of the histogram are erased before filling by the new values except if a precedes the name as in histol In this case the data is appended to the histo If the name hwork is given but there is no already existing histogram of that name a new one is created with standard characteristics option is an option string that is passed to the drawn histogram of type THIF This is equivalent to the TH1 class drawing options The reader can go to the address http root cern ch to see the list of options in the drawing of a TH1 see Classes and Members Reference Guide Examples Let s assume that a time series vect contains data starting at t 0 and has a duration of 1 s with 50000 samples The min value is 123 the max value is 212 gVM gt DrawHist vect 0 2 0 4 will draw the histogram of the values in vect beginning at t6 0 2 s for a duration of 0 4 s The generated histogram has limits 130 223 hl new THIF h1 test histo 100 25 25 gVM gt DrawHist vect 0 2 0 4 h1 will generate the histogram h1 with limits 25 25 Calling the DrawHist method will fill this histogram but only with the values in its range So one can concentrate on the distribution of values around 0 gVM gt DrawHist vect 0 2 0 4 h1 This will do the same thing
80. nce each frame channel has its reference time setting it is done by the VFrameChannel method SetRefTime Easy void SetRefTime double reftime void SetRefTime char when int leapseconds 0 xreftime is the GPS time expressed as a double to take care of fractions of seconds when is a character string that may be one of the following e now for the time at which this setting is done script executed or command typed at the command line e start for the beginning time of the first frame indexed by the information database It s the database start time e astring describing the time universal time in the format day month year 4 digits hour 1 24 minute seconds For example 12 04 2000 21 15 34 leapseconds is the number of leap seconds that was the reference at the specified time This is necessary since we are internally using the GPS time When you express the time as 12 04 2000 21 15 34 it will be converted in universal time UTC referring to earth s rotation But GPS is a number of seconds since a reference date Earth s rotation being non uniform these two times drift with respect to each other The amount of drifting is the number of leap seconds It is automatically given in a frame header or in a vector In case you don t know it let it to O Be aware that you may have a difference of around 30 seconds beginning 2000 The number of leap seconds is as of today increasing by appro
81. nterpreter V 6 2 Filling an N tuple and getting data The ExtractSMS method of VFrameChannel does the job for you in case you want to extract SMS data It is nevertheless useful to know how to fill an ntuple and access the data that is inside it in case you want to loop on this data void Fill Float_t x void Fill Float_t x0 Float_t xl Float_t x2 0 Float_t x3 0 Float_t x4 0 Float_t x5 0 Float_t x6 0 Float_t x7 0 Float_t x8 0 Float_t x9 0 Float_t x10 0 Float_t x11 0 Float_t x12 0 Float_t x13 0 Float_t x14 0 xis an array of floats x0 to x14 in case you have less than 15 variables and more than 1 2 or more you can call the second form of the Fill method Example vnt gt Fi11 1 43 4 23 b c d will fill the ntuple with the values specified One can fill an ntuple in a loop as much as he wants especially if the ntuple is on disk To make an ntuple on disk simply open a ROOT file in RECREATE mode BEFORE building the ntuple This one will automatically be attached to the file and it s contents will be flushed to disk as soon as the buffers are full every 32 kbytes by default void GetEntry Int_t i Float_t GetArgs Extracts the variables corresponding to a given entry in the ntuple iis the index of the entry in filling order GetEntry fills an internal array with the contents of entry i and GetArgs returns a pointer to an array of floats containing the values There are two different met
82. ntry 3 Entry 4 f 1 Parameter 1 Parameter 2 Parameter 3 The difference with a simple array is that each leaf of the tree can be any kind of object even a tree itself This leads to a hierarchical structure like in a directory structure for a file system In fact these more general ntuples are called Trees In simple ntuples as VNtuples each leaf is a single float parameter VNtuples are derived from ROOT TNtuples and therefore have access to all the methods available in TNtuples We will focus on the ones that were added and on the ones most frequently used For the others the reader may refer to http root cern ch root html TNtuple html V 6 1 Building VNtuple The standard constructor is VNtuple Text_t name Text_t title Text_t listofvariables Int_t bufsize 32000 name is the name of the new VNtuple title is its title listofvariables is the list of variables to be put in the ntuple It is a char string made of names separated by colons For example t x y z var1 This list will tell what is the number of variables to be foreseen bufsize is the buffer size used internally when writing to disk The default value is sufficient for most uses Example vnt new VNtuple vnt Example vntuple t TP1 TP2 PR1 PR2 will build a new ntuple object with 5 variables In a compiled program vnt has to be declared as a VNtuple before use It will be automatically declared if one uses the i
83. nu SX data pig i VIRGO Data Display JI X Signal processing and algorithms The signal processing functions present in VEGA rely on the Frv analysis library developped in VIRGO A default version of the library is provided with the VEGA sources but may be upgraded at any time The API of this library are not yet finalized but come very close to this point This library uses the FFTW http www fftw org library for computing fft s The installation of FFTW is not difficult and described in the installation documents i e INSTALL file in the distribution or Installation of ROOT The sources and documentation of Frv may be found http wwwlapp in2p3 fr virgo FrameL We will just give an example to demonstrate the use of the library to make an FFT of a vector A structure FrvRFFT that holds the result of an fft transform of a frame vector FrVect is defined The algorithm itself is build and called with FrvRFFTFor 0 frvect as for example in suppose vect is an FrVect vega fft FrvRFFTFor 0 vect This will create a standard fft and apply it to the vector vect On output the fft structure contains the result of the processing in the form of FrVect s that one can plot as usual vega gVM gt Draw fft gt amplitude For the amplitude part of the fft Once the fft object is not needed anymore the user should delete it with vega FrvRFFTFree fft Look at the example scrollsp
84. ocess only a subset of the frames corresponding to some conditions say amplitude of the trigger Trig1 higher than a certain value When building a metadatabase the trigger information is read from the frame and saved This allows for a frame channel when using a metadatabase to quickly browse it searching for frames that obey a given set of conditions Let s illustrate the use of this feature with our tutorial test files We will suppose that wis the frame channel opened in the previous paragraph The frames contained in the tutorial files were generated with two trigger structures Trig and Trig2 which have various amplitudes for the various frames First we may try to see the value of a given trigger amplitude by plotting it The database object w has the capability to draw it vega w gt DrawCondition Trigl amp Trigl This will plot the amplitude of the trigger Trig1 provided it is defined The second string Trig1 is a selection expression so one can plot only the amplitude of selected triggers if necessary The second step is to define the selection expression with a set of conditions which will govern the search for specific frames This is done by defining a new object called a condition set class VConditionSet that will contain the selection expression and serve as a pointer to a specified position in the metadatabase Each type of metadatabase needs it s own type of condition sets So we have to ask it th
85. ogram It will be displayed by default when the histogram is drawn gt 100 8 8 are the number of bins nbins xlow and xup For PAW users you don t have to worry about the type of xlow and xup integers will be converted to floats gRandom gt SetSeed Another global gRandom is the current object of the class TRandom of standard random generators You probably already noticed that all globals begin with a g 1 2 followed by a capital letter This is general and belongs to the coding conventions used in ROOT which are followed by VEGA The SetSeed method of TRandom chooses a random seed here the default one The class TRandom doesn t try to be overly ambitious The important methods are e SetSeed iseed sets the seed of the random number generator If no number is given 65536 is used e Gaus mean sigma return a random number distributed following a gaussian with mean and sigma e Rannor a b returns two random numbers following a gaussian with mean 0 and sigma 1 e Rndm returns a uniformly distributed random number in the interval 0 1 Float_t xgauss To avoid machine dependence of raw C types double float and especially int etc the basic types have been typedefed So instead of float we use Float_t 4 byte float You can equally well use standard types float double for your everyday work In VEGA we integrated the Framelib which has its own machine independent data types To avoi
86. onditions expressed in the selection expression selection are valid This time interval is the nearest next one to the time gpstime Thus gpstime is not the start time of the vector but the start time of the search The string nameofvect indicates the type adc proc sim and the name of the series to be extracted The convention for the format is type name For example adc IFO_DMRO is a good format If only the name is given the groups of series in the frame will be searched in the order adc proc sim for that name If more than one identical name was defined in the frame the first found series with that name will be used The first method starts the search at an absolute time the second at a time relative to the reference time see chapter Dealing with time For example vega vect fc gt GetNextVect adc IFO_DMRO gpstime Trig1 gt 50 Will return a vector of type FrVect Frames where the condition expression Trig1 gt 50 will be first searched for This will give a start time and length for the time interval of interest Then the vector of type adc and named IFO_DMRO will be assembled whose start time and length will match those of the interval If only the name is given the groups of series in the frame will be searched in the order adc proc sim for that name If more than one identical name was defined in the frame the first found series with that name will be used V 5 4 2 Sequential methods
87. ope to provide in the near future as many tools as possible for example a set of standard algorithms as well as an interface to Matlab Tutorials written by Andrew Haas University of Washington Mark Pollack RHIC and Fons Rademakers in part inspired this document Thanks to them 1 1 What is ROOT ROOT is a system for large scale data analysis and data mining It is being developed for the analysis of Particle Physics data but can equally well be used in other fields where large amounts of data need to be processed ROOT is not a computer program but instead is a set of over 300 C classes and an interactive C interpreter So one can use it as a framework just using existing classes and libraries in his programs Or one can use the interactive part of the interpreter to execute tasks defined by the user on the command line or run macros which are in fact made of C code Once the user is satisfied with his macro he can compile it since it is nothing else than C with a little extra effort and run it much faster 1 2 Objectives of this document This User s Manual is written with the beginner or casual user in mind Therefore the first chapter is an interactive one in the sense that the best way to read it is in front of a computer with a VEGA session opened Next chapters are more for reference People that will begin to work with VEGA will usually have a FORTRAN or C background I will suppose that the user is a
88. out century For time H Hour 24 hour clock I Hour 12 hour clock Sp Local equivalent of AM or PM SM Minute 00 59 S Seconds 00 61 SS For example the standard string used in Europe is d m y H M 9 VIII 2 2 2 Set axis time parameters in a script In a script one will need to set unset change the time format or parameters with statements There are two ways VIII 2 2 2 1Directly The first is to access the axis object of the plot It is of type TAxis and given a plot vs is accessed via vs gt GetXaxis or vs gt GetYaxis Suppose we have a vector ve of type FrVect already extracted A typical use would be Draw the vector and get the associated VSPplot vega gVM gt Draw vect vega vs gVM gt GetLastPlot Set the time display on the X axis In order to do this since time display are axis characteristics one first accesses the axis object with vs gt GetXaxis and then calls the Set TimeXxx method vega vs gt GetXaxis gt SetTimeDisplay Set the time format vega vs gt GetXaxis gt SetTimeFormat a user format of course replace a user format by what you want to be the format Format options are described in the previous paragraph V111 2 2 2 2Through the style The second possible way is to use the gVStyle variable so that you set it once and all the subsequent plots will be drawn with the specified options as for example time on ax
89. ow monitoring station MYGOSMS in our case The last two parameters are the start time from which we want the extraction and the length expressed in seconds This ntuple will have three variables the time being the first variable automatically inserted during extraction If you want to see the contents of the ntuple do vega nt gt Print Now that we have a ntuple one can easily plot all sort of things For example if you want to plot the variations of VF1 with time vega nt gt DrawGraph t MYGOSMS VF1 at The second empty parameter is a selection parameter One can overlay a second plot vega nt gt DrawGraph t MYGOSMS VI2 1 One can also use some complicated expressions for example vega nt gt DrawGraph t sqrt MYGOSMS VF1 MYGOSMS VI2 MYGOSMS VF1 gt sqrt MYGOSMS VI2 50 at Where you can see that the expressions can use the standard operators and simple 23 mathematical functions One can also plot a histogram of some columns of the ntuple vega nt gt Draw MYGOSMS VF1 MYGOSMS VI2 lego2 See the result and try to rotate interactively the drawn histogram 24 IV More on C for the interested reader This paragraph is intended to introduce the reader to some useful insights into C to allow some use of the most advanced features found in ROOT It is in no case a full course in C IV 1 C notions used classes methods and constructors You can try to use
90. presentation of your graph Fe cl Eile Edit View Options You can rotate interactively this 2D plot Of course it is possible to plot real 2D functions or graphs not only a disguised 1D There are numerous ways to change the graphical options colors fonts with the various methods available in the popup Here are a few examples FE atttext title of x i EE ae ES ne CORRE ms BETT i FS attline f1 808 ORS 2k times bold i normal times bold r normal 08000 082208 0808 R R e a pve 2 Line attributes Text attributes Fill attributes Once the picture suits your wishes you may want to see what are the lines of code you should put in a macro to obtain the same result To do that choose the Save as canvas C option in the Files menu This will generate a macro that you can look into to see how to set the various options Notice that you can also save in postscript or gif formats the picture One other interesting possibility is to save in native root format your canvas This will enable you to open it again and to change whatever you like since all the objects associated to the canvas histograms graphs etc are saved at the same time 11 2 6 Second example Building a multi pad canvas Let s now try to build a canvas i e a window with several Pads The pads are sub windows that can contain other Pads or graphical objects vega can n
91. ration triggers etc is in one place and data itself is in another place A frame channel will link the two searching for information about data where it is and using it to access data It will act as a data provider The metadata may take many forms It may be a metadatabase that will be described elsewhere it may be a bookkeeping database or it may be the frame files themselves that contain enough information to be used by a frame channel We will start by using the simplest form which is the direct use of the files Let s open such a frame channel with the demo frame files vega fc new VFrameChannel file demo400000000 F demo400000045 F The operator new described elsewhere is creating an object of the class VFrameChannel returning a pointer fc The argument of the constructor the function attached to the class that builds the objects of this class are the names of the frame files that will be used in our case demo400000000 F and demo400000045 F The characters file are used to tell the frame channel which type of meta information it should use in this case simple files NOTE Since it s annoying to always type long names one can use the tab completion feature of ROOT using the lt Tab gt key Here lt Tab gt represents the Tab key on the keyboard NOT the letters lt T a b gt vega w new VFrameC lt Tab gt and the name is completed automatically This is also true for names of files in the curr
92. rawHist fr adc MYGO ADC1 0 13 0 07 hisfr el Update the canvas gPad gt Update FrameFree fr fr vd gt GetNextFrame Get the next frame Fits the histogram and draws the fit result hisfr gt Fit gaus hisfr gt SetMarkerColor 4 hisfr gt SetMarkerStyle 8 hisfr gt SetMarkerSize 0 7 hisfr gt Draw el 84 XII 4 Example 4 Extracting some slow monitoring data and doing some simple plots This example shows how to extract slow monitoring data and plot variables or combinations of them The example is in the macro sms C This example shows how to plot a set of slow monitoring values To see the result of this macro click begin_html lt a href gif sms gif gt here lt a gt end_html A ntuple is build and used to plot various combinations of variables gROOT gt Reset Open a new window canvas cl new TCanvas cl1 A slow monitoring example 1 Creates the needed pads by dividing the initial canvas cl gt Divide 1 2 Opens the frame channel vdsms new VFrameChannel SMSdemoDB root First builds the ntuple from the MYGOSMS station values nt vdsms gt ExtractSMS nt MYGOSMS 400000000 5000 Then draws the plots cl1 gt cd 1 select the first pad Sets some style options gStyle gt SetMarkerColor 50 gStyle gt SetMarkerStyle 8 gStyle gt SetMarkerSize 0 5 Draws the value VF1
93. rough the frame channel to create a suitable condition set vega cs w gt CreateConditionSet Trigl amp gt 50 amp amp Trig2 gt 0 The selection expression may use standard C operators and the main C math functions sin Trigl amp gt 0 23 Trig2 0 is a valid expression Now one calls repeatedly the GetNextFrame cs method of VFrDataBase to get all the frames corresponding to the selection To illustrate this let s load the next selected frame and see it s beginning time vega fr w gt GetNextFrame cs vega fr gt GTimeS unsigned int 400000120 Do not forget that fr is a FrameH structure and as such we can use its internal variables such as GTimeS the start time You see that the start time is obviously far from the start time of the first frame 400000001 All the frames in between were skipped since they did not obey the selection expression If you use repeatedly GetNextFrame do not forget to delete the object fr after it s use with FrameFree fr otherwise your memory will get filled by all the undeleted frames that were passed to you 111 8 How to deal with slow monitoring data Slow monitoring data spans a lot of frames Thus it requires a special treatment To illustrate this let s build a database with frame files containing only SMS data One such file was build by the create_testfr macro Its name is SMSdemo F Check that you have such a file Then open a frame channel with for example
94. row new TArrow 1 5 89 124 this will call the constructor of TArrow but also the constructor of TLine which is the parent class of TArrow automatically Then we want to set the size of the head myarrow gt SetArrowSize 10 and draw it myarrow gt Draw IV 3 C notions used operators new and delete Why is it so interesting to use new and delete instead of malloc and free First the operator new knows the size of the object it has to initialize You don t need to play with it Second and the most important new calls the specified constructor of the class the object belongs to No need to do special initialization you have to think about it when you write your classes constructor But new also calls the constructor of all the objects that your class contains For example the class TPad contains a list of all objects in the pad This list is itself an object of the class TList and there is a call to the constructor of this list in the constructor of TPad We will see that new calls also automatically the constructor of the parent class see the inheritance paragraph When you begin to use new don t use malloc anymore Better said try to avoid mixing new and malloc There is a risk to use free instead of delete to release a memory that was allocated by new This is guaranteed to crash 30 V Accessing and managing Gravitational Waves data V 1 Accessing frames through the Framelib The Framelib is
95. rt x gt gt hsqrt y gt 0 will draw sqrt x and save the histogram as hsqrt in the current directory By default the specified histogram is reset To continue to append data to an existing histogram use in front of the histogram name vnt gt Draw sqrt x gt gt thsqrt y gt 0 will not reset hsqrt but will continue filling option is an option for drawing The following options are supported on all types SAME Superimpose on previous picture in the same pad CYL Use Cylindrical coordinates POL Use Polar coordinates SPH Use Spherical coordinates DSR Use PseudoRapidity Phi coordinates LEGO Draw a lego plot with hidden line removal LEGO1 Draw a lego plot with hidden surface removal LEGO2 Draw a lego plot using colors to show the cell contents SURF Draw a surface plot with hidden line removal SURF1 Draw a surface plot with hidden surface removal SURF2 Draw a surface plot using colors to show the cell contents SURF3 same as SURF with in addition a contour view drawn on the top SURF4 Draw a surface using Gouraud shading The following options are supported for 1 D types AH Draw histogram but not the axis labels and tick marks B Bar chart option CP Draw a smooth Curve through the histogram bins E Draw error bars EO Draw error bars including bins with o contents E
96. s drawn with option AP to draw the axis and subsequent plots that the user wants to overlay are plotted with the P option alone nentries is the maximum number of entries to be processed in the ntuple firstentry is the first entry to be processed The second method draws histograms This is mainly used for statistical studies void Draw Text_t varlist Test_t cuts Text_t option Int_t nentries 1000000000 Int_t firstentry 0 Unlike in DrawGraph which needs at least two variables to plot a graph one can plot a 1D 2D or 3D histogram The variables have the same meaning as in DrawGraph but the varlist can contain the name of an existing histo and options are not the same varlist is an expression of the general form e1 e2 where el etc is a formula referencing a combination of the ntuple columns Example varexp x y simplest case draw a plot of points x y x and y representing columns named x and y t sqrt x draw plot of sqrt x vs t log t x y z Note that the variables el or e2 may contain a selection example if el x y lt 0 the value plotted will be x if y lt O and will be O otherwise One can save the result of Draw to a histogram By default the temporary histogram created is called htemp If varlist contains gt gt hnew following the variable s name s the new histogram created is called hnew and it is kept in the current directory See the class TDirectory of ROOT Example vnt gt Draw sq
97. se on previous picture in the same pad CYL Use Cylindrical coordinates POL Use Polar coordinates SPH Use Spherical coordinates PSR Use PseudoRapidity Phi coordinates LEGO Draw a lego plot with hidden line removal LEGO 1 Draw a lego plot with hidden surface removal LEGO2 Draw a lego plot using colors to show the cell contents SURF Draw a surface plot with hidden line removal SURF1 Draw a surface plot with hidden surface removal SURF2 Draw a surface plot using colors to show the cell contents SURF3 same as SURF with in addition a contour view drawn on the top SURF4 Draw a surface using Gouraud shading AH Draw plot but not the axis labels and tick marks B Bar chart option Ig Draw a smooth Curve through the plot points E Draw error bars EO Draw error bars including bins with o contents E1 Draw error bars with perpendicular lines at the edges E2 Draw error bars with rectangles E3 Draw a fill area through the end points of the vertical error bars E4 Draw a smoothed filled area through the end points of the error bars L Draw a line through the plot points P Draw current marker at each point H Draw plot with a at each point The second method draws graphs sets of points defined by two coordinates It will be used in the case of data sets irregularly spaced in time void DrawGraph Text_t varlist Test _t cuts T
98. sed to have XIII 3 Building a standalone executable XIII 3 1 Building an executable that is linked with the ROOT and VEGA libraries The directory test contains a few examples of programs that use the VEGA and ROOT classes The main metadb cc and main display cc programs are just skeletons that may be used as a starting point to build bigger programs The main difficulty for their compilation is to put all the necessary includes and to link with all the necessary libraries Furthermore one has to use the same compiler as the one used for compiling ROOT and VEGA This ensures the less possible problems In order to simplify as much as possible the determination of the various includes libraries or parameters to use a utility script is provided called vega config that shows them This utility is generated at VEGA compile time and returns all the parameters used for compiling VEGA For example to determine what C compiler was used do vega vega config cxx g XIII 3 2 Options of the vega config utility The options available for vega config are the following help prints a help message metadb set only output parameters includes libraries relevant to metadatabase for the following options display set only output parameters includes libraries relevant to display for the following options signal set only output parameters includes libraries relevant to signal for
99. ss of this plot is added to the list of plots managed by this manager The name of the plot becomes the name of the FrVect Options e The ones of the TH1 class for example same which superimposes a plot to a previous draw e sameti does a similar superposition but respects the time i e will shift the plot so that it s time and the one of a previously drawn vector coincide Examples Suppose a time series vector vect contains data starting at t 0 and has a duration of 1 s with 50000 samples gVM gt Draw vect will draw the entire series gVM gt Draw vect 0 3 0 2 will draw the series starting at t 0 3 s for a duration of 0 2 s which represents 10000 samples gVM gt Draw vect same will draw the entire series on the same plot as a previous draw Drawing the distribution histogram of the data contained in an FrVect void DrawHist FrVect vect Float_t offset 1e20 Float_t dur 1e20 const Text_t hwork Option_t option Makes a distribution of the values contained in a series This method generates or uses a histogram of the class THIF If the histogram is generated its limits are determined automatically to be 5 of the max and min value in the series and this histogram has 100 bins The variables are offset is the offset from which the histogramming starts with respect to the starting value of the series dur is the length of the histogramed part of the series hwork is optio
100. t are plotted a peak at the beginning of the frames The histogram is accumulated for nframmax frames To see the result of this macro click here gROOT gt Reset FrameH fr Double t time Max number of frames displayed Int_t nframmax 14 Open a new window canvas and divide it by 2 cl new TCanvas cl cl1 1 cl gt Divide 2 1 cl _1 gt SetFillColor 44 cl _1 gt SetFrameFillColor 41 ci 2 gt SetFillColor 44 cl 2 gt SetFrameFillColor 41 cl_2 gt SetLogy cl_2 gt SetGridx cl_2 gt SetGridy Open a frame channel vd new VFrameChannel demoDB root Start time time 400000000 1 Histogram to constrain the limits hisfr new THIF hisfr Histogram of MYGO_ Seis values 100 0 3000 hisfr gt SetMarkerColor 4 hisfr gt SetMarkerStyle 8 hisfr gt SetMarkerSize 0 7 Get the first frame fr vd gt GetFrame time Int_t nfram 0 while fr 0 amp amp nfram lt nframmax nframtt printf nfram dn nfram Draws the vector only in the signal region c1 gt cd 1 gVM gt Draw fr adc MYGO_ADC1 0 13 0 07 Get the corresponding VSPlot and set the color to blue VSPlot vfp gVM gt GetLastPlot vfp gt SetLineColor 4 Fill the histogram accumulates it and draw it the option in front of the name of the histogram means that it s content is not erased before each fill cl gt cd 2 gVM 83 gt D
101. t example User interaction If you quit the framework try to draw again the function sin x x Now we can look at some interactive capabilities Every graphics drawn in a window which is called a Canvas is in fact a graphical object in the sense that you can grab it resize it change some characteristics with a mouse click And all the changes that you do are not done on a graphical copy of the object but on the object itself For example try to click somewhere on the x axis and drag along this axis You have a very simple zoom When the cursor is on any object you have access to selected methods by pressing the right mouse button and obtaining a context menu showing some available methods for this object If you try this on the function itself you obtain this kind of behavior c1 BEIE File Edit View Options Inspect Classes Help DrawPanel SetMaximum SetMinimum SetFillAttributes SetMarkerAttributes You can try for example to select the SetRange method and put 10 10 in the dialog box fields This is equivalent to executing the member function f1 SetRange 10 10 from the command line prompt followed by 1 Draw There are other things you may want to try For example select the DrawPanel item of the popup menu You will see a panel like this one Try to resize the bottom slider and click Draw You can zoom your graph If you click on lego2 and Draw you see a 2D re
102. tasks For the moment this is not so important since the amount of created vectors frames is not big 1 5 Extracting a 2D vector image from the frame channel and plotting it The vectors inside a frame may be two dimensional and may represent an image coming from a camera 2D vectors are plotted the same way as 1D vectors For example assuming ve2 is a 2D vector of type FrVect vega gVM gt Draw ve2 will draw it Let s see a concrete example using the files contained or generated in the vegatutorial directory First open a frame channel vega fc new VFrameChannel file demo400000000 F demo400000045 F second extract the first frame using this frame channel vega fr fc gt GetNextFrame third since the name of the vector containing the image is MYGO_IMAGE plot it vega gVM gt Draw fr MYGO IMAGE col That s it The option col used for this drawing produces a color plot Other options are shown in the chapter Representing gravitational waves data A few tutorials explain how to do it more generally moveimage C tifrdisplay C for example 11 6 Building a metadatabase for more complex tasks In case one uses files containing frames that are not sequentially ordered or wants to use a selection or condition mechanism for the frames the frame channel does not get enough information with a direct file access as described above There is a necessity to build a metadatabase that will conta
103. the scripts you are going to produce It starts by calling the C compiler that was used to build ROOT and builds a shared library This shared library is then loaded and the function defined in the script is executed 11 4 1 Preparation of the script 1 3 So that seems nice what is the deal It s only that you have to prepare a little bit your script But it is quite simple You have to NOT use extensions to C C provided by the CINT interpreter That means for example that while in the interpreter you do not need to declare variables whose type is known from the context this is mandatory if you want to be able to compile Since the compiler is not supposed to know the context of the interpreter An example In the interpreter you can use statements like cl new TCanvas cl Test 1 where you do not declare the variable c1 you should do instead TCanvas cl new TCanvas cl Test 1 More generally use very standard C C and declare all your variables You should add includes you use at the beginning of the file Once again this is for the real compiler that will do the work Usually the headers to be added are composed of the name of the classes used followed by the h suffix In case of included C code the most commonly used are FrameL h for all the Framelib calls and the standard headers of the Virgo standard signal library In case you want to execute immediately i e use the command x the
104. ult Returns the result of the condition formula that is used to define the condition set applied to the current set of conditions When searching for the next condition set this result should be non zero double Eval const char formula Returns the result of the formula formula applied to the current set of conditions This allows to see in a set of conditions the status of a particular condition For example if fc is a valid frame channel suppose the specified condition set is vega cs fc gt CreateconditionSet Trigl a gt 2 amp amp Trig2 a lt 20 The fact that you jumped to the next valid condition set with a GetNextVect or GetNextFrame call see VFrameChannel ensures that the condition Trigl a gt 2 amp amp Trig2 a lt 20 is satisfied But you may wonder what is the real value of the amplitude of condition Trig1 This may be known with vega cs Eval Trigl a double 11 876 V 6 N tuples adapted for GW data analysis Slow monitoring data spans a lot of frames The special treatment we have to apply in order to gain a simple yet efficient way of dealing with SMS data is to builda special object called an ntuple that will contain all this data We developed a particular ntuple VNtuple that differs from the standard ROOT one in that it is adapted to our needs You can think of a ntuple as a list of all the sms data putin a tree like structure NTuple Entry 1 Entry 2 E
105. will be written in bold characters 11 1 Basic intrinsic operations First of all one needs to know how to exit from a program The C interpreter has some raw commands that begin with a dot These commands are used to do intrinsic operations not related to any C C code The ones that you should know for the beginning are q quits the interactive session X loads a macro and executes it We will see other raw commands as we need them especially commands to debug scripts step step over set breakpoint etc 11 2 The interpreter CINT graphical interaction through a few examples 11 2 1 First very simple example First go to the ROOTSYS tutorials and start the ROOT VEGA interactive session your _prompt vega The prompt that you see is vega In fact you launched the very small vega executable which is in VEGA UNAME and which is linked with the ROOT libraries This program gives access via a command line prompt to all available ROOT VEGA classes globals functions By typing C C statements at the prompt you can create objects call functions execute scripts etc For example type vega 1 sqrt 9 double 4 000000000000e 00 vega for int i 0 i lt 5 i printf Hello d n i A Hello 0 Hello 1 Hello 2 Hello 3 Hello 4 vega q As you can see if you know C or C you can use ROOT No new command line or scripting language to learn Some comments may be made at this point First there
106. with respect to time t is automatically filled as the first variable of the ntuple at extraction nt gt DrawSeries MYGOSMS VF1 P vs gVM gt GetLastPlot vs gt SetTitle Sets some style options gStyle gt SetLineColor 4 Superimposes the values of sqrt VI2 50 it s an example nt gt DrawSeries sqrt MYGOSMS VI2 50 same 85 Draws a title for the graphs pl new TPaveLabel 400 135 1000 156 VF1 sqrt VI2 50 br pl gt Draw In the second pad draws a histogram of values VF1 with respect to sqrt V1I2 50 cl gt cd 2 select the second pad Draws the histogram nt gt Draw MYGOSMS VF1 sqrt MYGOSMS VI2 50 cont0 Here is the result of this macro F A slow monitoring example Iof x File Edit View Options Inspect Classes Help 40 oohoo oohio coh20 oohse coh40 cohso cihoc othie othe HYGOSMS VF1 sqt M VY GOSMS Vi2 50 86 XILS5 Example 5 Extracting a vector and plotting spectra This example shows how to use the fft algorithms to plot spectra The example is in the macro scrollspectrum C This simple example opens a demo metadatabase plots a vector and it s spectrum The vector is scrolled 1 s at a time nvecmax times The extraction of the vector shows that one can select a vector without having to think about the frame boundaries The length of t
107. xcerpt of the header file defining the class THIF public virtual void Fill Axis_t x virtual void Fill Axis_t x Stat_t w virtual void Fill Axis_t x Axis_t y Stat_t w virtual void Fill Axis_t x Axis_t y Axis_t z Stat_t w You see that the Fill method is defined four times with different arguments How does the compiler know what method to call For the compiler to be able to make the difference the arguments must be different enough There is no ambiguity in the Fill methods above since the number of parameters is different for each method If someone had made the following statement public virtual void Fill Axis_t x virtual void Fill Axis_t x Stat_t w 1 where in the second declaration one of the arguments has a default value this is permitted in C then the compiler doesn t know which method to call if someone uses h1 gt Fil1 23 Should the compiler use the form Fill Axis_t x where x 23 or the form Fill Axis t x Stat t w 1 where x 23 and one uses the default value w 1 In that case the compiler sends an error message So one must be careful when writing his methods not to come in such situations Easier said than done 11 4 How to compile a macro Sometimes in fact quite often a script may become so big or be so processing hungry that one would like to have it compiled and not interpreted There is included into ROOT what is called a script compiler that allows compiling very easily
108. ximately a little bit more than 1s per year Example If fc is a frame channel object opened previously vega fc gt SetRefTime start will set the reference time to be the start of the info database vega fc gt SetRefTime 12 04 2000 21 15 34 will set the reference time to the specified date putting leap seconds to 0 May have a 30 seconds difference with what is expected vega fc gt SetRefTime 12 04 2000 21 15 34 32 will set the reference time to the specified date putting leap seconds to 32 This will be much more correct VIII 2 Time when outputting information VHI 2 1 Plotting frames or vectors start time From Framelib version v4r0 each FrVect vector has its absolute GPS beginning time included In VEGA this start time is automatically plotted below the VSPlot produced when drawing vectors Though the default behavior should be all right for most users one may change the options used for drawing this time by using the global variables gVStyle that holds the style options for the VEGA session It is described in chapter The global variables often used To change the default behavior one should set the values in gVStyle BEFORE drawing the vector These are the x offset the y offset and the display on off state as shown below 68 IVVU 0 0 01 002 003 0 04 005 0 06 time sec fwo ffset One could use the following methods of gVStyle VStyle SetStartTimeDisplay true_or_false
109. y else This may seem a little bit confusing and the reader should read a good C book if he she wants more details Especially since besides public and private a member can be protected But this is another story Usually one puts private the methods that the class uses internally like some utility classes and that the programmer doesn t want to be seen in the outside world With good C practice which we suppose is used in ROOT all data members of a class are also set private This is called data encapsulation and is one of the strongest advantages of Object Oriented Programming OOP By doing that nobody can see the data members of a class except the class itself So from the outside world if one wants to access those data members one should use so called getters and setters methods which are special methods used only to get or set the data members The advantage is that if the programmer wants to modify the inner workings of his class he can do so without changing what the user sees The user doesn t even have to know that something has changed for the better hopefully An example In our TArrow class we would have set the data member ArrowHeadSize private The setter method is SetArrowSize we don t need a getter method class TArrow public TLine private int ArrowHeadSize public void Draw void SetArrowSize int arrowsize If one wants to define an arrow he does TArrow myar

D. Buskulic LAPP / Université de Savoie

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D. Buskulic LAPP / Universit&eacute; de Savoie

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D. Buskulic LAPP / Université de Savoie