Frequently Asked Questions, PDF
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1. Back to Question 1 9 2 10 Shared Libraries The Shared Libraries directory was introduced to make it easier for design teams to exchange models and work on group projects It is possible to develop a library within the environment specified by the MLD_USER environment variable and then move this library to the shared environment specified by the SMLD_SHARED environment variable However since the SMLD_USER variable is dynamic because it can be different for every user the following prerequisite applies e All modules and files needed by systems in the library must be located within this library or in a location that never changes such as the directory to which MLD_SHARED and MLD point The reason for this is that the systemName mm1 file contains references to all model elements needed for the system to function If these variables change then MLDesigner will not be able to locate the missing model elements Back to Question 1 10 2 6 MLDesigner Version 2 82. This error is often caused by compiler incompatibility What version of make do you use You need gmake 3 74 or later Please look at the section on system requirements in the app Back to Question 1 2 2 Answers to FAQ s 2 3 Segmentation Faults System Crashes The most common reason for system crashes with MLDesigner is programmer error in user de fined primitives When a segmentation fault occurs you should first check to see if your system contains user defined primitives Often the crash is caused by inconsistencies in memory allocated to output datasets The next step is to run the simulation extern possibly using an external debug ger to debug the system External simulations occur outside of the MLDesigner environment See the MLDesigner manual index for more information on debugging Back to Question 1 3 2 4 Data Structures 1 When to clone a particle Generally you don t have to clone particles In sending particles over the ports you can use operators like lt lt or For data structures the situation is more complicated because you have to take into account how it is instantiated as a data structure and how it is used When to create a new particle When you instantiate a new data structure for direct us age not to be used as parameter in a method that takes const Typex as parameter meth ods of setType kind you have to use the method DsHandler makeNewStructure When is a particle a clone When you
3. you prefer click the Settings option in the main menu Expand the tree by clicking the Primitive Source Editor item as shown in fig 2 1 The following options are available 1 Use external editors with xterm Some editors open in a terminal and others not Often the terminal is not required and only gets in the way To stop the xterm from opening with your editor click the check box to remove the tick If the editor cannot open without a console you will get an error message in the MLDesigner console when attempting to open a source file In this case make sure you have a tick in the check box Try open vi without a tick in this check box or set the editor variable to emacs in the EDITOR input field 2 Internal This points to the built in editor installed with MLDesigner 3 EDITOR This radio button sets the default editor to the one you have defined by setting your environment variable i e For sh and bash command shells export EDITOR emacs For csh and tesh command shells setenv EDITOR emacs You must close and restart MLDesigner before changes take effect 4 User defined Has the same effect as the EDITOR radio button except you do not have to close and reopen MLDesigner to get the new setting to work You must only change the MLDesign 2 3 Technologies ms 2 Answers to FAQ s editor name The are variables that instruct the editor you choose to open the source code of the open primitive in your Model Editor Wi
4. Frequently Asked Questions Version 2 8 February 26 2010 MLDesign Technologies Inc 2130 Hanover St Palo Alto CA 94306 support www midesigner com support M LDesign http www mldesigner com Technologies ML Designer Version 2 8 Chapter 1 Frequently Asked Questions This chapter is designed to help you find quick and short answers to your questions All these topics are covered in detail in the ML Designer user manual which can be opened by clicking the Help button in the top right corner of the GUI and selecting the option Search Index 1 1 General Questions Do I need to learn Ptolemy and BONeS to be able to design with MLDesigner Go to Answer 2 1 1 2 Error Messages and Their Most Common Causes 1 Cannot create library xxx to location file user xxx yyy zzz xxx mml Maybe you have no write permission Cannot create model xxx You must create the library yyy first Go to Answer 1 2 Compilation error unable to load the primitive Dynamic Go to Answer 2 3 make fatal error in reader export home mldesigner mk config default mk line 59 Un expected end of line seen Go to Answer 3 1 3 Segmentation Faults What are the most common causes of segmentation faults that cause MLDesigner to crash Go to Answer 2 3 1 4 Data Structures 1 When must a data structure be deleted and when is it a clone 2 What is a memory leak Go to Answer 2 4 1 Frequently Asked Que
5. MLDProject in your home directory Set your MLD_USER environment variable to point to the new directory When you open MLDesigner again you will see the tree view with ML Designer libraries and no user libraries You could then create a top level library with read and write rights for a workgroup on your network Back to Question 1 7 Use an External Debugger Depending on the type of shell you are using enter one of the following at the prompt export MLD_PREBIN ddd sh and bash or setenv MLD_PREBIN ddd csh and tcsh The ddd entry refers to the ddd debugger supplied with every Linux package and can be replaced with a call referring to your favorite debugger You must now start MLDesigner as normal The debugger you have chosen will start If you are using ddd proceed as follows e Click the View menu and choose Command Tool e Click Run to start ML Designer This can take longer than normal e You can now work as normal with ML Designer Back to Question 1 7 Differences Between MLD_USER and Working Directory SMLD_USER and Working Directory are not related to each other at all The variable SMLD_USER defines where MLDesigner looks for user defined models and libraries where the option Working Directory defines which directory is the working directory for the command console window after starting MLDesigner Both these topics are explained in the MLDesigner manual which can be opened by clicking on the Sea
6. e load mode Dynamic a shared library containing the primitive code is created on loading This shared library is linked dynamically to MLDesigner so that you can reload the primitive any time All changes made to the primitive are effective immediately Conversely by selecting load mode Permanent the primitive is linked to MLDesigner on loading as it would be with a built in 2 2 MLDesigner Version 2 8 2 6 Plotting Systems primitive All changes made to a primitive with load mode permanent only take effect after closing and restarting MLDesigner Back to Question 1 5 2 6 Plotting Systems 1 There are a number of ways to display or handle datasets and results of simulations e You may use SatLab to display data see Demos DopplerIR you need to start SatLab before running the demo It uses a Tcl script MLD MLD _Libraries DE Contrib WiNeS tcl e You may save your data to one or more files and postprocess display it with another tool of your choice You could for example use a DEPrinter primitive to dump data to a file then use GnuPlot Matlab or even a spreadsheet program like StarCalc within StarOffice to display the information Back to Question 1 6 2 7 Setting Environment Variables Change the Default Editor To define the editor you prefer to use when working with source code it is no longer necessary to set the environment variables A dialog is available where a variety of setting can be changed To define which editor
7. ndow MLDesigner General a Model Editor E Primitive Source Editor En Colors A Fonts Run Control D Conversion l Log Window le r General IV Use external editors with xterm Standard Editor Internal EDITOR User defined User defined vi Cancel Restore Defaults Help Figure 2 1 Generated hypertext documentation m NOTE The built in editor is used as default editor in cases where compile errors occur The reason is that you can highlight errors in the built in editor error console and the cursor will be automatically placed in the correct line of the source code editor Back to Question 1 7 Set the MLD_USER variable It is possible to set your MLD_USER environment variable to point to a project library or external library Lets assume you want to work on a project called MLD project This project is the MLD_USER directory of another user You want to access the systems and share libraries that exist in the other user s environment Enter the following command where you would normally open MLDesigner e for bash or sh shells export MLD_USER home user MLD project e for tcsh and csh shells 2 4 MLDesigner Version 2 8 2 8 Using ddd Debugger under Red Hat setenv MLD_USER home user MLD project You could also do the same locally on your own computer if you wanted to separate libraries and projects You can create a new directory
8. rch Index option of the Help menu found in the top right corner of the GUI Find the index entries Command Console or Working Directory to get more detail on the topic Back to Question 1 7 2 8 Using ddd Debugger under Red Hat It is not possible to debug MLDesigner using ddd because Red Hat was developed completely using GCC 2 96 contrary to the recommendations of the Free Software Foundation see http www fsf org software gee gee 2 96 html MLDesign 2 5 Technologies mx 2 Answers to FAQ s As a result ddd compiled under GCC 2 96 needs a symbol dynamic_cast_2 defined in libstdc libc6 2 2 s0 3 With a SuSE system compiled using GCC 2 95 running under Red Hat the system crashes when accessing the system internal libstdc 1i1bc6 2 2 so 3 This is apparently caused by a change in the library interface At the moment there are no solutions to the problem and we can only suggest you to use gdb or xxgdb as an alternative debugger Back to Question 1 8 2 9 Linked Objects Files containing object code must be loaded before the primitive that calls the external functions in the object file is compiled All changes made to the external library will only be actualized when MLDesigner is shutdown and restarted The reason is that it is not possible to delete the relevant primitive from memory without conflicts arising in the kernel s reload mechanism The result would be a primitive containing a mixture of new and old code
9. rts of the same type Back to Question 1 1 2 2 Error Messages and Their Causes 1 This error message normally occurs when you do not have permission to write to the target directory or to one of the directories higher in the hierarchical structure Another reason could be caused by a file that is write protected in the target directory when you have checked the option Overwrite existing Files in the appropriate Import dialog window Back to Question 1 2 2 There are a number of reasons for this error message e Firstly your primitive contains syntactical errors and can not be compiled by the C compiler In that case you will get an error dialog Compilation failed when you compile the primitive in MLD You should open the primitive editor try to compile it and correct the reported errors until successful compilation is confirmed e Secondly a primitive with the same name already exists in the same Domain e Another reason could be the primitive was already loaded with Load mode set to Per manent If a Primitive is loaded permanent it is not possible to make any changes to its source code and then recompile the primitive You must shutdown MLDesigner and restart before the changes take effect You only need to load a primitive as permanent if you want it to be inherited by another primitive A primitive that is a child of another primitive can only be recompiled if the parent is loaded as permanent Back to Question 1 2 3
10. set a data structure to a Memory Event or a DataStructMember the parameter is cloned inside the method so there is no need for a new created object When to delete a data structure When you get a data structure using the method DsHandler makeNewStructure be sure to delete it to avoid overloading mem ory Every new data structure created using the clone method must be deleted The exception is when you place it on an output port DataStructParticles take care to delete the data structure when the last reference to it is deleted Do not delete const pointers to Type or class derivedfrom returned by some methods These are references to the class members and the object takes care of deleting them On the contrary non const pointers to Types must be deleted if you are not in the exceptional case previously mentioned Do not delete particles when As an exception don t delete the non const Typex returned by DataStructMember s methods getData or fieldWithName of the DataStructure class or every time when you write or read a Memory using writeMemory 2 A Memory Leak occurs when new memory is allocated dynamically and never deallocated In C new memory is created by the new operator and deallocated by the delete or the delete operator Memory leaks accumulate over time and can crash the program Back to Question 1 4 2 5 Load Mode While creating a new primitive model component you can define its load mode By selecting th
11. stions 1 5 Load Mode What is the difference between Load Mode Dynamic and Load Mode Permanent Go to An swer 2 5 1 6 Plotting Systems How do I make data available to or save data for analysis using external programs Go to An swer 2 6 1 7 Setting Environment Variables 1 How do I change the environment variables so I can use another Editor to debug or change source code in my primitives Go to Answer 2 7 2 How do I change the MLD_USER environment variable Go to Answer 2 7 3 How do I change the environment variables so I can use an external debugger Go to Answer 2 7 4 Is setting the Working Directory entry the same as setting the MLD_USER environ ment variable Go to Answer 2 7 1 8 ddd debugger and Red Hat I am running MLDesigner under Red Hat and I am unable to debug using the standard debugger ddd Go to Answer 2 8 1 9 Linked Objects Why must I restart MLDesigner before changes made to Linked Object take effect Go to An swer 2 9 1 10 Shared Libraries What is the environment variable MLD_SHARED used for and how do I set this variable Why are there invalid modules in my Shared Libraries Go to Answer 2 10 1 2 MLDesigner Version 2 8 Chapter 2 Answers to FAQ s 2 1 Answers for the General Questions No but it is necessary to bear in mind that the Ptolemy base type int is different to any data structure type including those like Root Integer It is only possible to connect po
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