JavaRes/src/atp/Clausifier.java at master · eprover/JavaRes · GitHub

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A simple implementation of Russel&Norvig's clausification algorithm.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program ; if not, write to the Free Software

Foundation, Inc., 59 Temple Place, Suite 330, Boston,

MA 02111-1307 USA

package atp;

import java.util.*;

public class Clausifier {

public static int varCounter = 0;

public static int skolemCounter = 0;

public static int axiomCounter = 0;

public static String typePrefix = "axiom";

/** ***************************************************************

* a->b is the same as -a|b

private static BareFormula removeImp(BareFormula form) {

BareFormula result = new BareFormula();

result.op = Lexer.Or;

BareFormula newLHS = new BareFormula();

newLHS.op = Lexer.Negation;

if (form.child2 != null)

result.child2 = removeImpEq(form.child2);

if (form.child1 != null)

newLHS.child1 = removeImpEq(form.child1);

if (form.lit1 != null)

newLHS.lit1 = form.lit1;

if (form.lit2 != null)

result.lit2 = form.lit2;

result.child1 = newLHS;

return result;

}

/** ***************************************************************

* a<-b is the same as a|~b

private static BareFormula removeBImp(BareFormula form) {

BareFormula result = new BareFormula();

result.op = Lexer.Or;

BareFormula newRHS = new BareFormula();

newRHS.op = Lexer.Negation;

if (form.child1 != null)

result.child1 = removeImpEq(form.child1);

if (form.child2 != null)

newRHS.child1 = removeImpEq(form.child2);

if (form.lit2 != null)

newRHS.lit1 = form.lit2;

if (form.lit1 != null)

result.lit1 = form.lit1;

result.child2 = newRHS;

return result;

}

/** ***************************************************************

* a<=>b is the same as

* (a->b)&(b->a)

private static BareFormula removeEq(BareFormula form) {

BareFormula result = new BareFormula();

BareFormula lhs = new BareFormula();

if (form.child1 != null)

lhs.child1 = form.child1;

if (form.child2 != null)

lhs.child2 = form.child2;

if (form.lit1 != null)

lhs.lit1 = form.lit1;

if (form.lit2 != null)

lhs.lit2 = form.lit2;

lhs.op = Lexer.Implies;

BareFormula rhs = new BareFormula();

if (form.child1 != null)

rhs.child2 = form.child1;

if (form.child2 != null)

rhs.child1 = form.child2;

if (form.lit1 != null)

rhs.lit2 = form.lit1;

if (form.lit2 != null)

rhs.lit1 = form.lit2;

rhs.op = Lexer.Implies;

result.op = Lexer.And;

result.child1 = lhs;

result.child2 = rhs;

return removeImpEq(result);

}

/** ***************************************************************

* a<=>b is the same as

* (a->b)&(b->a)

* a->b is the same as -a|b

private static BareFormula removeImpEq(BareFormula form) {

if (form.op.equals(Lexer.Implies)) {

return removeImp(form);

}

else if (form.op.equals(Lexer.Equiv)) {

return removeEq(form);

}

else if (form.op.equals(Lexer.BImplies)) {

return removeBImp(form);

}

else {

BareFormula result = form.deepCopy();

if (result.child1 != null)

result.child1 = removeImpEq(result.child1);

if (result.child2 != null)

result.child2 = removeImpEq(result.child2);

return result;

}

/** ***************************************************************

* -(p | q) becomes -p & -q

* -(p & q) becomes -p | -q

* -![X]:p becomes ?[X]:-p

* -?[X]:p becomes ![X]:-p

* --p becomes p

* @param flip when true indicates to change the operator of the given

* literal

private static Literal moveNegationIn(Literal lit, boolean flip) {

if (!flip)

return lit;

Literal result = lit.deepCopy();

if (result.atom.getFunc().equals(Lexer.EqualSign) && flip)

result.atom.t = Lexer.NotEqualSign;

else if (result.atom.getFunc().equals(Lexer.NotEqualSign) && flip)

result.atom.t = Lexer.EqualSign;

else

result.negated = !result.negated;

return result;

}

/** ***************************************************************

private static BareFormula moveNegationIn(BareFormula form) {

return moveNegationIn(form,false);

}

/** ***************************************************************

private static String flipOperator(String s) {

if (s.equals("|"))

return "&";

else if (s.equals("&"))

return "|";

else if (s.equals("~|"))

return "|";

else if (s.equals("~&"))

return "&";

else if (s.equals("!"))

return "?";

else if (s.equals("?"))

return "!";

return s;

}

/** ***************************************************************

* -(p | q) becomes -p & -q

* -(p & q) becomes -p | -q

* -![X]:p becomes ?[X]:-p

* -?[X]:p becomes ![X]:-p

* --p becomes p

private static BareFormula moveNegationIn(BareFormula form, boolean flip) {

//System.out.println("INFO in Clausifier.moveNegationIn(): " + form + " " + flip);

BareFormula result = form.deepCopy();

if (result.op.equals("~")) { // there is no child2 or lit2 in this case

//System.out.println("INFO in Clausifier.moveNegationIn(): has a negation: " + result);

if (flip) {

//System.out.println("INFO in Clausifier.moveNegationIn(): negations cancel: " + result);

if (result.child1 != null)

result = moveNegationIn(result.child1,false);

if (result.lit1 != null)

result.lit1 = moveNegationIn(result.lit1,false);

}

else {

//System.out.println("INFO in Clausifier.moveNegationIn(): negation with no flip: " + result);

if (result.child1 != null) {

result = moveNegationIn(result.child1,true);

}

else if (result.lit1 != null) { // should handle a no-op parent

result.lit1 = moveNegationIn(result.lit1,true);

result.op = "";

}

else {

if (flip) {

//System.out.println("INFO in Clausifier.moveNegationIn(): flipping: " + result);

result.op = flipOperator(result.op);

if (result.child2 != null)

result.child2 = moveNegationIn(form.child2,true);

if (result.child1 != null)

result.child1 = moveNegationIn(form.child1,true);

if (result.lit1 != null && !BareFormula.isQuantifier(result.op))

result.lit1 = moveNegationIn(form.lit1,true);

if (result.lit2 != null)

result.lit2 = moveNegationIn(form.lit2,true);

}

else {

//System.out.println("INFO in Clausifier.moveNegationIn(): 5: " + result);

if (result.child2 != null)

result.child2 = moveNegationIn(form.child2,false);

if (result.child1 != null)

result.child1 = moveNegationIn(form.child1,false);

if (result.lit1 != null && !BareFormula.isQuantifier(result.op))

result.lit1 = moveNegationIn(form.lit1,false);

if (result.lit2 != null)

result.lit2 = moveNegationIn(form.lit2,false);

}

//System.out.println("INFO in Clausifier.moveNegationIn(): 6 returning: " + result);

return result;

}

/** ***************************************************************

private static Term generateNewVar() {

return Term.string2Term("VAR" + Integer.toString(varCounter++));

}

/** ***************************************************************

* The scope of variables in quantifiers is local to the quantifier,

* but to avoid confusion, variables of the same name but different scope

* in a formula are renamed.

* ![X]:p(X) | ?[X]:q(X) becomes

* ![X]:p(X) | ?[Y]:q(Y)

public static BareFormula standardizeVariables(BareFormula form) {

BareFormula result = form.deepCopy();

if (form.child1 != null)

result.child1 = standardizeVariables(form.child1);

if (form.child2 != null)

result.child2 = standardizeVariables(form.child2);

if (BareFormula.isQuantifier(form.op)) {

Substitutions subst = new Substitutions();

Term oldVar = form.lit1.atom;

Term newVar = generateNewVar();

subst.addSubst(oldVar,newVar);

return result.substitute(subst);

}

return result;

}

/** ***************************************************************

private static BareFormula moveQuantLeftChild(BareFormula form) {

//System.out.println("Child1 has quantifier. Current result: " + form);

BareFormula newParent = new BareFormula();

newParent.op = form.child1.op;

newParent.lit1 = form.child1.lit1; // child1 has quantifier list

BareFormula newChild = new BareFormula();

newParent.child2 = newChild;

if (form.child2 != null)

newChild.child2 = form.child2;

if (form.lit2 != null)

newChild.lit2 = form.lit2;

if (form.child1.child2 != null)

newChild.child1 = form.child1.child2;

if (form.child1.lit2 != null)

newChild.lit1 = form.child1.lit2;

newChild.op = form.op;

//System.out.println("Child1 has quantifier. New result: " + newParent);

return newParent;

}

/** ***************************************************************

private static BareFormula moveQuantRightChild(BareFormula form) {

//System.out.println("Child2 is not null: " + form.child2);

//System.out.println("Child2 has quantifier. Current result: " + form);

BareFormula newParent = new BareFormula();

newParent.op = form.child2.op;

newParent.lit1 = form.child2.lit1; // child2 has a quantifier list

BareFormula newChild = new BareFormula();

newParent.child2 = newChild;

if (form.child1 != null)

newChild.child1 = form.child1;

if (form.lit1 != null)

newChild.lit1 = form.lit1;

if (form.child2.child2 != null)

newChild.child2 = form.child2.child2;

if (form.child2.lit2 != null)

newChild.lit2 = form.child2.lit2;

newChild.op = form.op;

//System.out.println("Child2 has quantifier. New result: " + newParent);

return newParent;

}

/** ***************************************************************

* [op1 child1 child2]

* [op2 lit1 child3] [op3 lit2 child4]

* becomes

* [op2 lit1 new1]

* [op3 lit2 new2]

* [op1 child3 child4]

private static BareFormula moveQuantBothChildren(BareFormula form) {

BareFormula newParent = new BareFormula();

BareFormula newMidChild = new BareFormula();

BareFormula newBottomChild = new BareFormula();

newParent.op = form.child1.op;

newParent.lit1 = form.child1.lit1;

newParent.child2 = newMidChild;

newMidChild.op = form.child2.op;

newMidChild.lit1 = form.child2.lit1;

newMidChild.child2 = newBottomChild;

newBottomChild.op = form.op;

if (form.child1.child2 != null)

newBottomChild.child1 = form.child1.child2;

if (form.child1.lit2 != null)

newBottomChild.lit1 = form.child1.lit2;

if (form.child2.child2 != null)

newBottomChild.child2 = form.child2.child2;

if (form.child2.lit2 != null)

newBottomChild.lit2 = form.child2.lit2;

return newParent;

}

/** ***************************************************************

* p|![X]q(X)

* becomes

* ![X]p | q(X)

private static BareFormula moveQuantifiersLeftIterate(BareFormula form) {

//System.out.println("INFO in Clausifier.moveQuantifiersLeft(): " + form);

//System.out.println("op: " + form.op);

if (form == null)

return null;

BareFormula result = form.deepCopy();

if (BareFormula.isQuantifier(form.op)) {

//System.out.println("Formula has quantifier(1): " + form);

result.op = form.op;

result.lit1 = form.lit1; // child1 not needed since it's null when there's a quantifier

result.child2 = moveQuantifiersLeftIterate(form.child2);

result.lit2 = form.lit2;

//System.out.println("Formula has quantifier: " + result);

return result;

}

if (form.child2 != null)

result.child2 = moveQuantifiersLeftIterate(form.child2);

if (form.child1 != null)

result.child1 = moveQuantifiersLeftIterate(form.child1);

if (result.child2 != null && BareFormula.isQuantifier(result.child2.op) &&

result.child1 != null && BareFormula.isQuantifier(result.child1.op)) {

changed = true;

return moveQuantBothChildren(result);

}

if (result.child2 != null && BareFormula.isQuantifier(result.child2.op)) {

changed = true;

return moveQuantRightChild(result);

}

if (result.child1 != null && BareFormula.isQuantifier(result.child1.op)) {

changed = true;

return moveQuantLeftChild(result);

}

return result;

}

private static boolean changed = true;

/** ***************************************************************

private static BareFormula moveQuantifiersLeft(BareFormula form) {

BareFormula result = form.deepCopy();

while (changed) {

changed = false;

result = moveQuantifiersLeftIterate(result);

}

return result;

}

/** ***************************************************************

private static Term generateNewSkolem(HashSet<Term> args) {

StringBuffer argList = new StringBuffer();

Iterator<Term> it = args.iterator();

while (it.hasNext()) {

Term t = it.next();

argList.append(t.toString());

if (it.hasNext())

argList.append(",");

}

if (argList.length() > 0)

return Term.string2Term("skf" + Integer.toString(varCounter++) + "(" + argList + ")");

else

return Term.string2Term("skf" + Integer.toString(varCounter++));

}

/** ***************************************************************

private static BareFormula skolemizationRecurse(BareFormula form,

HashSet<Term> uList) {

//System.out.println("INFO in Clausifier.skolemizationRecurse(): " + form);

//System.out.println(uList);

BareFormula result = form.deepCopy();

if (form.child1 != null)

result.child1 = skolemizationRecurse(form.child1,uList);

if (form.child2 != null)

result.child2 = skolemizationRecurse(form.child2,uList);

if (form.op.equals("?")) { // existential

Term var = form.lit1.atom;

Term skolem = generateNewSkolem(uList);

Substitutions subst = new Substitutions();

subst.addSubst(var,skolem);

//System.out.println("calling substitution with: " + subst);

result = result.substitute(subst);

result.op = ""; // not sure if this is ok

if (result.child2 != null)

result = result.child2;

//System.out.println("returning result: " + result);

return result;

}

if (form.op.equals("!")) // universal

uList.add(form.lit1.atom);

return result;

}

/** ***************************************************************

* Create a unique function in place of every existentially quantified variable.

* Include every universally quantified variable that is in scope, inside the function.

* ![X]:p(X) => (?[Y]:h(Y) & a(X,Y))

* becomes

* ![X]:p(X) => (h(skf(X)) & a(X,skf(X)))

private static BareFormula skolemization(BareFormula form) {

return skolemizationRecurse(form,new HashSet<Term>());

}

/** ***************************************************************

* Remove universal quantifiers

private static BareFormula removeUQuant(BareFormula form) {

BareFormula result = form.deepCopy();

if (form.child1 != null)

result.child1 = removeUQuant(form.child1);

if (form.child2 != null)

result.child2 = removeUQuant(form.child2);

if (form.op.equals("!")) {

return result.child2;

}

else

return result;

}

/** ***************************************************************

* (a & b) | c becomes (a | c) & (b | c)

private static BareFormula distributeAndOverOrRecurse(BareFormula form) {

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): " + KIF.format(form.toKIFString()) + " " + changed);

BareFormula result = form.deepCopy();

if (form.child1 != null)

result.child1 = distributeAndOverOr(form.child1);

if (form.child2 != null)

result.child2 = distributeAndOverOr(form.child2);

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): (2): " + KIF.format(form.toKIFString()));

if (form.op.equals("|")) {

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): top level or: " + KIF.format(form.toKIFString()));

if (result.child1 != null && result.child1.op.equals("&")) {

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): child1 and: " + KIF.format(form.toKIFString()));

BareFormula newParent = new BareFormula();

newParent.op = "&";

BareFormula newChild1 = new BareFormula();

newChild1.op = "|";

if (result.child1.child1 != null)

newChild1.child1 = result.child1.child1;

if (result.child1.lit1 != null)

newChild1.lit1 = result.child1.lit1;

if (result.child2 != null)

newChild1.child2 = result.child2;

if (result.lit2 != null)

newChild1.lit2 = result.lit2;

BareFormula newChild2 = new BareFormula();

newChild2.op = "|";

if (result.child1.child2 != null)

newChild2.child1 = result.child1.child2;

if (result.child1.lit2 != null)

newChild2.lit1 = result.child1.lit2;

if (result.child2 != null)

newChild2.child2 = result.child2;

if (result.lit2 != null)

newChild2.lit2 = result.lit2;

newParent.child1 = newChild1;

newParent.child2 = newChild2;

changed = true;

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): result: " + KIF.format(newParent.toKIFString()));

return newParent;

}

else if (result.child2 != null && result.child2.op.equals("&")) {

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): child2 and: " + KIF.format(form.toKIFString()));

BareFormula newParent = new BareFormula();

newParent.op = "&";

BareFormula newChild1 = new BareFormula();

newChild1.op = "|";

if (result.child2.child1 != null)

newChild1.child1 = result.child2.child1;

if (result.child2.lit1 != null)

newChild1.lit1 = result.child2.lit1;

if (result.child1 != null)

newChild1.child2 = result.child1;

if (result.lit1 != null)

newChild1.lit2 = result.lit1;

BareFormula newChild2 = new BareFormula();

newChild2.op = "|";

if (result.child2.child2 != null)

newChild2.child1 = result.child2.child2;

if (result.child2.lit2 != null)

newChild2.lit1 = result.child2.lit2;

if (result.child1 != null)

newChild2.child2 = result.child1;

if (result.lit1 != null)

newChild2.lit2 = result.lit1;

newParent.child1 = newChild1;

newParent.child2 = newChild2;

changed = true;

//System.out.println("INFO in Clausifier.distributeAndOverOrRecurse(): result: " + KIF.format(newParent.toKIFString()));

return newParent;

}

return result;

}

/** ***************************************************************

private static BareFormula distributeAndOverOr(BareFormula form) {

BareFormula result = form.deepCopy();

changed = true;

while (changed) {

changed = false;

result = distributeAndOverOrRecurse(result);

}

return result;

}

/** ***************************************************************

private static ArrayList<BareFormula> separateConjunctions(BareFormula form) {

ArrayList<BareFormula> result = new ArrayList<BareFormula>();

if (form.op.equals("&")) {

if (form.child1 != null)

result.addAll(separateConjunctions(form.child1));

if (form.child2 != null)

result.addAll(separateConjunctions(form.child2));

}

else

result.add(form);

return result;

}

/** ***************************************************************

* (a | b) | c becomes a | b | c

private static Clause flatten(BareFormula form) {

Clause result = new Clause();

if (!Term.emptyString(form.op) && !form.op.equals("|")) {

System.out.println("Error in Clausifier.flatten(): operator '" + form.op + "' is not a disjunction");

return result;

}

if (form.lit1 != null)

result.add(form.lit1);

if (form.lit2 != null)

result.add(form.lit2);

if (form.child1 != null)

result.addAll(flatten(form.child1).literals);

if (form.child2 != null)

result.addAll(flatten(form.child2).literals);

return result;

}

/** ***************************************************************

private static ArrayList<Clause> flattenAll(ArrayList<BareFormula> forms) {

ArrayList<Clause> result = new ArrayList<Clause>();

for (int i = 0; i < forms.size(); i++) {

BareFormula form = forms.get(i);

Clause c = flatten(form);

c.name = "cnf" + Integer.toString(axiomCounter++);

c.type = typePrefix;

result.add(c);

}

return result;

}

/** ***************************************************************

public static ArrayList<Clause> clausify(BareFormula bf) {

BareFormula result = bf.deepCopy();

BareFormula newresult = SmallCNFization.formulaOpSimplify(result);

if (newresult != null)

result = newresult;

result = removeImpEq(result);

result = moveNegationIn(result);

result = standardizeVariables(result);

result = moveQuantifiersLeft(result);

result = skolemization(result);

result = removeUQuant(result);

result = distributeAndOverOr(result);

ArrayList<BareFormula> forms = separateConjunctions(result);

ArrayList<Clause> clauses = flattenAll(forms);

return clauses;

}

/** ***************************************************************

public static ArrayList<Clause> clausify(Formula f) {

typePrefix = f.type;

return clausify(f.form);

}

/** ***************************************************************

* *************** Unit Tests ******************

/** ***************************************************************

private static void testRemoveImpEq() {

System.out.println();

System.out.println("================== testRemoveImpEq ======================");

BareFormula form = BareFormula.string2form("a=>b");

System.out.println("input: " + form);

form = removeImpEq(form);

System.out.println(form);

System.out.println();

form = BareFormula.string2form("a<=>b");

System.out.println("input: " + form);

form = removeImpEq(form);

System.out.println(form);

System.out.println();

form = BareFormula.string2form("((((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X,f(Y)))))<=>q(g(a),X))");

System.out.println("input: " + form);

form = removeImpEq(form);

System.out.println(form);

System.out.println();

}

/** ***************************************************************

private static void testMoveQuantifiersLeft() {

System.out.println();

System.out.println("================== testMoveQuantifiersLeft ======================");

BareFormula form = BareFormula.string2form("p|![X]:q(X)");

System.out.println("input: " + form);

form = moveQuantifiersLeft(form);

System.out.println("result should be ![X]:p | q(X): " + form);

System.out.println();

form = BareFormula.string2form("~((![X]:a(X)) | b(X))");

System.out.println("input: " + form);

form = moveQuantifiersLeft(form);

System.out.println("result: " + form);

System.out.println();

form = BareFormula.string2form("~(((![X]:a(X)) | b(X)) | (?[X]:(?[Y]:p(X, f(Y)))))");

System.out.println("input: " + form);

form = moveQuantifiersLeft(form);

System.out.println("result: " + form);

System.out.println();

form = BareFormula.string2form("( (~(((![X]:a(X)) | b(X)) | (?[X]:(?[Y]:p(X, f(Y)))))) | q(g(a), X))");

System.out.println("input: " + form);

form = moveQuantifiersLeft(form);

System.out.println("result: " + form);

System.out.println();

form = BareFormula.string2form("( ( (~(((![X]:a(X)) | b(X)) | (?[X]:(?[Y]:p(X, f(Y)))))) | q(g(a), X)) & " +

"((~q(g(a), X)) | (((![X]:a(X)) | b(X)) | (?[X]:(?[Y]:p(X, f(Y)))))))");

System.out.println("input: " + form);

form = moveQuantifiersLeft(form);

System.out.println("result: " + form);

System.out.println();

}

/** ***************************************************************

private static void testMoveNegationIn() {

System.out.println();

System.out.println("================== testMoveNegationIn ======================");

BareFormula form = BareFormula.string2form("~(p | q)");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be -p & -q: " + form);

System.out.println();

form = BareFormula.string2form("~(p & q)");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be -p | -q: " + form);

System.out.println();

form = BareFormula.string2form("~![X]:p");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be ?[X]:-p: " + form);

System.out.println();

form = BareFormula.string2form("~?[X]:p");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be ![X]:-p: " + form);

System.out.println();

form = BareFormula.string2form("~~p");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be p: " + form);

System.out.println();

form = BareFormula.string2form("(~(?[Y]:p(X, f(Y))))");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result: " + form);

System.out.println();

form = BareFormula.string2form("(~(?[X]:(?[Y]:p(X, f(Y)))))");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("expected result: (![X]:(![Y]:~p(X, f(Y))))");

System.out.println("result: " + form);

System.out.println();

form = BareFormula.string2form("~(((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X, f(Y)))))");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("result should be ( ((?[X]:(~a(X))|~b(X)) & (![X]:(![Y]:~p(X, f(Y)))) ): ");

System.out.println("actual: "+ form);

System.out.println();

form = BareFormula.string2form("(((~(((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X, f(Y))))))|q(g(a), X))&((~q(g(a), X))|(((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X, f(Y)))))))");

System.out.println("input: " + form);

form = moveNegationIn(form);

System.out.println("expected: ( ( ((( (?[X]:~a(X)) & ~b(X)) & (![X]:(![Y]:~p(X, f(Y)))) )) | q(g(a), X)) & " +

"((~q(g(a), X)) | (((![X]:a(X))|b(X)) | (?[X]:(?[Y]:p(X, f(Y)))) )))");

System.out.println("result: " + form);

System.out.println();

}

/** ***************************************************************

private static void testStandardizeVariables() {

System.out.println();

System.out.println("================== testStandardizeVariables ======================");

BareFormula form = BareFormula.string2form("~((![X]:a(X)) | b(X))");

System.out.println("input: " + form);

form = standardizeVariables(form);

System.out.println("result should be : ~((![VAR2]:a(VAR2)) | b(VAR1))");

System.out.println("actual: "+ form);

System.out.println();

form = BareFormula.string2form("(((~(((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X, f(Y))))))|q(g(a), X))&((~q(g(a), X))|(((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X, f(Y)))))))");

System.out.println("input: " + form);

form = standardizeVariables(form);

//System.out.println("result should be : ~((![VAR2]:a(VAR2)) | b(VAR1))");

System.out.println("actual: "+ form);

System.out.println();

}

/** ***************************************************************

private static void testSkolemization() {

System.out.println();

System.out.println("================== testSkolemization ======================");

BareFormula form = BareFormula.string2form("(?[VAR0]:(![VAR3]:(![VAR2]:(?[VAR5]:(![VAR1]:(?[VAR4]:((((~a(VAR0)&~b(X))&~p(VAR2, f(VAR1)))|q(g(a), X))&(~q(g(a), X)|((a(VAR3)|b(X))|p(VAR5, f(VAR4)))))))))))");

System.out.println("input: " + form);

form = skolemization(form);

System.out.println("actual: "+ form);

System.out.println();

}

/** ***************************************************************

private static void testDistribute() {

System.out.println();

System.out.println("================== testDistribute ======================");

BareFormula form = BareFormula.string2form("(a & b) | c");

System.out.println("input: " + form);

form = distributeAndOverOr(form);

System.out.println("result should be : (a | c) & (b | c)");

System.out.println("actual: " + form);

System.out.println();

form = BareFormula.string2form("(a & b) | (c & d)");

System.out.println("input: " + form);

form = distributeAndOverOr(form);

System.out.println("result should be : (a | c) & (a | d) & (b | c) & (d | b)");

System.out.println("actual: " + form);

System.out.println();

KIF.init();

form = BareFormula.string2form("(((~holdsAt(VAR2, VAR1)|releasedAt(VAR2, plus(VAR1, n1)))|(happens(skf3, VAR1)&terminates(skf3, VAR2, VAR1)))|holdsAt(VAR2, plus(VAR1, n1)))");

System.out.println("input: " + form);

form = distributeAndOverOr(form);

System.out.println("actual: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

}

/** ***************************************************************

private static void testClausificationSteps(String s) {

KIF.init();

System.out.println();

System.out.println("================== testClausification ======================");

BareFormula form = BareFormula.string2form(s);

System.out.println("input: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = removeImpEq(form);

System.out.println("after Remove Implications and Equivalence: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = moveNegationIn(form);

System.out.println("after Move Negation In: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = standardizeVariables(form);

System.out.println("after Standardize Variables: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = moveQuantifiersLeft(form);

System.out.println("after Move Quantifiers: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = skolemization(form);

System.out.println("after Skolemization: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = removeUQuant(form);

System.out.println("after remove universal quantifiers: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

form = distributeAndOverOr(form);

System.out.println("after Distribution: " + form);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

ArrayList<BareFormula> forms = separateConjunctions(form);

System.out.println("after separation: " + forms);

System.out.println(KIF.format(form.toKIFString()));

System.out.println();

ArrayList<Clause> clauses = flattenAll(forms);

System.out.println("after flattening: " + clauses);

System.out.println();

}

/** ***************************************************************

private static void testClausification() {

//testClausificationSteps("((((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X,f(Y)))))<=>q(g(a),X))");

testClausificationSteps("(![Fluent]:(![Time]:(((holdsAt(Fluent, Time)&(~releasedAt(Fluent, plus(Time, n1))))&(~(?[Event]:(happens(Event, Time)&terminates(Event, Fluent, Time)))))=>holdsAt(Fluent, plus(Time, n1)))))).");

}

/** ***************************************************************

private static void testClausificationSimple() {

System.out.println();

System.out.println("================== testClausificationSimple ======================");

BareFormula form = BareFormula.string2form("((((![X]:a(X))|b(X))|(?[X]:(?[Y]:p(X,f(Y)))))<=>q(g(a),X))");

System.out.println("input: " + form);

System.out.println();

ArrayList<Clause> result = clausify(form);

for (int i = 0; i < result.size(); i++)

System.out.println(result.get(i));

}

/** ***************************************************************

private static void testFileClaus(String filename) {

System.out.println();

System.out.println("================== testClaus ======================");

ClauseSet cs = Formula.file2clauses(filename);

for (int i = 0; i < cs.clauses.size(); i++)

System.out.println(cs.clauses.get(i));

}

/** ***************************************************************

public static void main(String[] args) {

//testRemoveImpEq();

//testMoveNegationIn();

//testMoveQuantifiersLeft();

//testStandardizeVariables();

//testSkolemization();

//testDistribute();

//testClausification();

//testClausificationSimple();

testFileClaus(args[0]);

}

JavaRes/src/atp/Clausifier.java at master · eprover/JavaRes · GitHub

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