THE SWAM USER MANUAL IN A NUTSHELL.
Contents
1. as operational semantics 4 1 The weak unification operator Bousi Prolog implements a weak unification operator denoted by which is the fuzzy counterpart of the syntactical unification operator of standard Prolog It can be used in the source language to construct expressions like Termi Term2 Degree which is interpreted as follows The expression is true if Term1 and Term2 are unifiable by similarity with approximation degree AD equal to Degree In general we can construct expressions Terml Term2 lt op gt Degree where lt op gt is a comparison arithmetic operator that is an operator in the set gt lt gt lt Observe that the expression Termi Term2 is syntactic sugar of Term1 Term2 gt 0 These expressions may be intro duced in a query as well as in the body of a clause WARNING In the present implementation the weak unification operator is denoted by instead of by used for the high level implementation of Bousi Prolog Also we use the symbol for representing similarity equations un WARNING In the high level implementation of Bousi Prologis possible to use the following construction Termi Term2 Degree which success if Term1 and Term2 are weak unifiable with approximation degree Degree other wise fails When Degree is a variable it is bound to the unification degree of Term1 and Term2 This construction is not available in2. the low level implemen tation of Bousi Prolog 4 2 Some limitations For the present version the SWAM does not implement all the features of full Bousi Prolog It implements a pure subset of Prolog with lists and arithmetic plus similarity equations and the weak unification operator However it does not implement Input Output predicates and the built in predicates described in the manual of the high level implementation of Bousi Prolog In the future we want to develop the SWAM to cover all the present and future features of Bousi Prolog in a more efficient implementation OBSERVATION Bousi Prolog uses the standard cut predicate of the Prolog language in an indirect way embedded into more declarative predicates and operators such as not weak negation as failure see below crisp negation as failure see below and gt if then and if then else operators However the low level implementation of Bousi Prolog we are describing imple ments the cut operator References 1 Pascual Julidn Iranzo and Clemente Rubio Manzano Introducing Weak Unifica tion into the WAM Dep of Information Technologies and Systems University of Castilla La Mancha Technical Report 2005 2 Maria I Sessa Approximate reasoning by similarity based sld resolution Theoret ical Computer Science 275 1 2 389 426 2002
3. THE SWAM USER MANUAL IN A NUTSHELL Pascual Julidn Iranzo and Clemente Rubio Manzano Department of Information Technologies and Systems University of Castilla La Mancha Pascual Julian Clemente Rubio uclm es 1 Introduction Bousi Prolog BPL for short is an extension of the Prolog language with simi larity relations The implementation we are describing is based on a subset of the Warren Abstract Machine plus some new techniques incorporated inside it to deal with flexible querying The result is what we call the Similarity Warren Abstract Machine SWAM The foundations and some implementation details of the SWAM can be found in 1 At the present time the SWAM is a prototype implementation and some bugs may arise during its execution Please send your comments to Clemente Rubio alu uclm es 2 Requirements and Instalation Procedure You need a computer running Windows 2000 or XP operating system and the Java Virtual Machine version 1 5 JVM 1 5 installed on it In order to install and execute the BPL environment you must follow these simple steps 1 Checks if the JVM 1 5 is installed If you need to install JVM 1 5 go to the URL address http java sun com javase downloads index_jdk5 jsp 2 Download the file bousi jar into the BPL home directory 3 Simply double click on the bousi jar file or if you have installed the Java SE Development Kit JDK follow these steps Located in the BPL home dir
4. ce in a computation by what we called a lambdacut When lambdacut is set the weak unifica tion process fails if the computed approximation degree goes below the stored lambdacut value Therefore the computation also fails and all possible branches starting from that choice point are discarded The lambdacut command can be used to set a new lambdacut value typing cut N into the query window you set the lambdacut value to N 4 The Bousi Prolog programming language In this section we briefly summarize the features of Bousi Prolog as it has been implemented in the present version supported by the SWAM We concentrate on the syntactical aspects The programming language we call Bousi Prolog is an extension of the stan dard Prolog language with a similarity relation defined on a syntactic domain Therefore the syntax is mainly the Prolog syntax but enriched with a built in symbol used for describing similarity relations actually fuzzy binary relations which are automatically converted into similarity relations by means of simi larity equations of the form lt alphabet symbol gt lt alphabet symbol gt lt similarity degree gt meaning that two constants n ary function symbols or n ary predicate symbols are similar with a certain degree A BPL program is a sequence of Prolog facts and rules plus a sequence of similarity equations Bousi Prolog uses the similarity based SLD principle 2 also called weak SLD resolution
5. ectory go to the Windows option and select Init Execute in the tool bar and write cmd Then a system console is opened Write java jar bousi jar or C lt BPL home directory gt java jar bousi jar into the command line Then the BPL environment is available 3 The BPL Environment In this section we give a brief tutorial in how to use the BPL environment wich is the interface between the user and the SWAM The BPL Environment is divided in two different zones The command op tions zone with the menu bar and the icon bar at the top of the screen and the windows zone The windows zone involves four kinds of windows The query window placed at the left bottom of the screen serves to in troduce a query to the system The out window shows the answers to a query an other system information You can delete the information in the out window by means of the command clear written into the query window The code area window shows the SWAM machine code obtained after the compilation of the source program It is the object program executed by the abstract machine You can delete the information in the code area window by typing the command reset into the query window The visualization window shows a pictorial representation of the Simi larity Matrix that is an adjacency matrix representation of the reflexive symmetric transitive closure of the original fuzzy binary relation which is computed startin
6. g from the set of similarity equations provided in the program As we shall comment is also possible to open several edit windows to create or modify programs 3 1 Creating new programs To create a new program you need to open a new edit window You select the new option on the File menu This may be done either by pulling down the mouse and selecting new or by typing the keys ctr1 N or by clicking the blank paper icon Once the new edit window has been created you may introduce your program A edit window is a basic full editor with the usual options The edit window does not send any input to the BPL system It only contains your program You can save your program into a file placed into the directory where the file bousi wam has been installed by pulling down the mouse and selecting save or by typing the keys ctr1 G or by clicking the diskette icon Also you can save your program into a specific directory either by pulling down the mouse and selecting save as or by typing the keys ctr1 M or by clicking the star diskette icon You may have more than one edit windows open WARNING It is important that the name of the file containing a BPL program has the suffix bpl 3 2 Editing a program Once a program has been stored on a disk you can open it in an edit window either by using the open option in the File Menu or by typing the keys ctr1 A or by clicking the opening archive icon 3 3 Compilation a
7. nd execution of a Program and a Query A BPL program is a set of facts rules and similarity equations plus a goal In order to launch it you must follow these steps 1 Create a new BPL program or open an old one 2 Pull down the mouse and select the option compile in the Action menu or type the keys ctr1 C or click the ok icon Once the program has been compiled the result of the compilation can be visualized in the out window If everything is ok the message is la compilacion se realizo correctamente Then the program can be executed 3 For executing the program select the execute option on the Action menu or type the keys ctr1 E or click on the sun icon WARNING If the current query success the answer is shown in the out window In order to obtain all the alternative answers you must write the interrogation key on the query window Also you can select the option More responses in the Action Menu o you can type the keys Ctr1 s 3 4 Miscellaneous The BPL environment provides two commands to reset the information shown by the out window and the code area window The command clear deletes the information shown in the out window In order to execute this command type clear into the query window The command reset deletes the information shown in the code area window In order to execute this command type reset into the query window We can impose a limit to the expansion of the search spa
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