com.evelopers.unimod.analysis
Class BooleanSimplifier

java.lang.Object
  com.evelopers.unimod.analysis.BooleanSimplifier

public class BooleanSimplifier

extends java.lang.Object

This class may be used to simplify formula, to merge set of formulae as conjunction or disjunction, to negate formula.

To check if set of formulae is complete, i.e. conjunction of the set is identical to true, call

 BooleanSimplifier bs = BooleanSimplifier.createBooleanSimplifier();
 AST node = bs.identicalToTrue(bs.or(formulaeSet));
 if (node.getType() == TRUE) {
   // Formulae set is complete
 } else {
  // node contains the conjunction. Disjunction of this node negated and formulaeSet
  //  will be identical to true
 }
 

To check if two of formulae are orthogonal, i.e. disjucntion of this formulae is identical to false, call

 BooleanSimplifier bs = BooleanSimplifier.createBooleanSimplifier();
 AST node = bs.identicalToFalse(bs.and(Arrays.asList(new AST[] {firstFormula, secondFormula})));
 if (node.getType() == FALSE) {
   // Formulae are orthogonal
 } else {
   // node contains the intersection of formulae. Conjunction of formulae and
   // negated node will be identical to false.
 }
 

Method Summary

antlr.collections.AST	and(java.util.Set astSet) Merges astSet to conjunction.
static BooleanSimplifier	createBooleanSimplifier()
boolean	equal(antlr.collections.AST f, antlr.collections.AST g) Checks is f is equal to g.
antlr.collections.AST	identicalToFalse(antlr.collections.AST ast) Checks if ast is identical to false.
antlr.collections.AST	identicalToTrue(antlr.collections.AST ast) Checks if ast is identical to true.
antlr.collections.AST	not(antlr.collections.AST ast) Negates ast.
antlr.collections.AST	or(java.util.Set astSet) Merges astSet to disjunction.
antlr.collections.AST	simplify(antlr.collections.AST ast) Converts formula to DNF and simplifies it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createBooleanSimplifier

public static BooleanSimplifier createBooleanSimplifier()

Returns:

instance of BooleanSimplifier

and

public antlr.collections.AST and(java.util.Set astSet)

Merges astSet to conjunction.

Parameters:

astSet - set to merge

Returns:

conjunction of astSet

or

public antlr.collections.AST or(java.util.Set astSet)

Merges astSet to disjunction.

Parameters:

astSet - set to merge

Returns:

disjunction of astSet

not

public antlr.collections.AST not(antlr.collections.AST ast)

Negates ast.

Parameters:

ast - formula to negate.

Returns:

negated formula.

simplify

public antlr.collections.AST simplify(antlr.collections.AST ast)
                               throws InterpreterException

Converts formula to DNF and simplifies it. If formula is identical to false then it is guaranteed that will be returned node with type FALSE.

Parameters:

ast - formula to simplify.

Returns:

simplified formula.

Throws:

InterpreterException - if ast isn't correct

identicalToFalse

public antlr.collections.AST identicalToFalse(antlr.collections.AST ast)
                                       throws InterpreterException

Checks if ast is identical to false.

Parameters:

ast - formula to check

Returns:

node with type FALSE if ast is identical to false. Simplified formula elsewise.

Throws:

InterpreterException

identicalToTrue

public antlr.collections.AST identicalToTrue(antlr.collections.AST ast)
                                      throws InterpreterException

Checks if ast is identical to true.

Parameters:

ast - formula to check

Returns:

node with type TRUE if ast is identical to true. Simplified formula elsewise.

Throws:

InterpreterException

equal

public boolean equal(antlr.collections.AST f,
                     antlr.collections.AST g)
              throws InterpreterException

Checks is f is equal to g.

Returns:

true if f is equal to g.

Throws:

InterpreterException