FCL example explained
What is jFuzzyLogic?
jFuzzyLogic is a fuzzy logic package written in java (as you might have guessed). It implements Fuzzy control language (FCL) specification (IEC 61131 part 7)
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How is it licensed?
jFuzzyLogic is open source. It is released mainly as "LGPLv3".If you prefer another open source license, just contact me and I'll try to add your preferred license as well (e.g. this is usualy done for companies using jFuzzyLogic in their commercial products).
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I'm getting an error "class file has wrong version ..."
That means your java version is too old and you should update it.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
How do I run the program?
Running the JAR file will show help:
java -jar jFuzzyLogic.jar Usage: java -jar jFuzzyLogic.jar [options] Options: file.fcl : Load FCL file and show memebership functions (default, when no option is provided). -c file.fcl : Compile. Generate C++ code from FCL file (to STDOUT) -e file.fcl in_1 in_2 ... in_n : Evaluate. Load FCL file, assign inputs i_1, i_2, ..., i_n and evaluate. demo : Run a demo exmaple (tipper.fcl) |
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How do I run the program demo?
In order to run a simple demo, you can run:
java -jar jFuzzyLogic.jar demo |
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How do I run an FCL file?
Running jFuzzyLogic.jar using an FCL file as argument, will show all the membership functions defined in the FCL file (assuming that the file has no errors, of course):
java -jar jFuzzyLogic.jar myfile.fcl |
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How do I run an FCL file for a given input?
Using the '-e' command line option, followed by the input variables values, will parse the FCL and run the fuzzy system usgin the input values provided.E.g.:
java -jar jFuzzyLogic.jar -e tipper.fcl 8.5 9 FUNCITON_BLOCK tipper VAR_INPUT food = 8.500000 VAR_INPUT service = 9.000000 VAR_OUTPUT tip = 24.999984 RULE_BLOCK No1 Support Rule name Rule 0.000000 1 IF (service IS poor) OR (food IS rancid) THEN tip IS cheap; 0.000000 2 IF service IS good THEN tip IS average; 0.750000 3 IF (service IS excellent) AND (food IS delicious) THEN tip IS generous; |
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How do I get the system's output programatically?
Using Fis.evaluate() you evaluate the FIS and returns void. In order to get any output variable, you can use fis.getVariable("variableName"). Here is a simple code snippet from TestTipper.java example (slightly modified):
public class TestTipper {
public static void main(String[] args) throws Exception {
FIS fis = FIS.load("fcl/tipper.fcl", true); // Load from 'FCL' file
fis.setVariable("service", 3); // Set inputs
fis.setVariable("food", 7);
fis.evaluate(); // Evaluate
System.out.println("Output value:" + fis.getVariable("tip").getValue()); // Show output variable
}
}
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How can I know which rules are used ?
You just need to take a look at the rule's "degree of support" (by default is printed when you print the rule). For instance here is a small example (it uses "tipper.fcl" file from the 'fcl' examples directory in the package):
package net.sourceforge.jFuzzyLogic;
import net.sourceforge.jFuzzyLogic.rule.Rule;
public class Zzz {
public static void main(String[] args) throws Exception {
FIS fis = FIS.load("fcl/tipper.fcl", true); // Load from 'FCL' file
fis.setVariable("service", 3); // Set inputs
fis.setVariable("food", 7);
fis.evaluate(); // Evaluate
System.out.println("Output value:" + fis.getVariable("tip").getValue()); // Show output variable
// Show each rule (and degree of support)
for( Rule r : fis.getFunctionBlock("tipper").getFuzzyRuleBlock("No1").getRules() )
System.out.println(r);
}
}
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The output is:
Output value:11.701603788948043 1 (0.25) if (service IS poor) OR (food IS rancid) then tip IS cheap [weight: 1.0] 2 (0.6666666666666666) if service IS good then tip IS average [weight: 1.0] 3 (0.0) if (service IS excellent) AND (food IS delicious) then tip IS generous [weight: 1.0] |
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How can I programatically add rules with three or more antecedents?
First of all, I have to tell you that hard-coding the rules is highly discouraged (pretty much like hard-coding values). If you absolutely must do it for whatever reason, here is an example on how to do it:
// RULE 3 : IF ((service IS good) OR (service IS excellent)) AND food IS delicious THEN tip is generous;
Rule rule3 = new Rule("Rule3", ruleBlock);
RuleTerm term1 = new RuleTerm(service, "good", false);
RuleTerm term2 = new RuleTerm(service, "excellent", false);
RuleTerm term3 = new RuleTerm(food, "delicious", false);
RuleExpression antecedentOr = new RuleExpression(term1, term2, new RuleConnectionMethodOrMax());
RuleExpression antecedentAnd = new RuleExpression(antecedentOr, term3, new RuleConnectionMethodAndMin());
rule3.setAntecedents(antecedentAnd);
rule3.addConsequent(tip, "generous", false);
ruleBlock.add(rule3);
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Remember that a rule antecedent is just a RuleExpression. A RuleExpression can be either a combination of RuleExpressions or RuleTerms. In your case, you'll have to use two RuleExpressions combined by a RuleConnectionMethodAndMin, i.e.:
IF (var1 IS low) AND ( (var2 IS medium) AND (var3 IS high) ) THEN .... |
This is because 'AND' accepts only 2 terms (all RuleExpressions accept one only or 2 terms).
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Where is the source code and where are the FCL examples?
The source code and the examples are in the JAR file. You can open it using WinZip (in windows) or 'unzip' command (in Unix and OsX).
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How do I create an Eclipse project that uses jFuzzyLogic?
Here is a video showing a step by step example of a project.Note: the java code is from TestTipper.java and the FCL code is from tipper.fcl file.
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