#include "nodeedge.h"
#include <string.h>
#include <stdlib.h>
+#include "inc_solver.h"
+#include "cnfexpr.h"
+
+/** Code ported from C++ BAT implementation of NICE-SAT */
VectorImpl(Edge, Edge, 16)
memcpy(n->edges, edges, sizeof(Edge)*numEdges);
n->flags.type=type;
n->flags.wasExpanded=0;
+ n->flags.cnfVisitedDown=0;
+ n->flags.cnfVisitedUp=0;
n->numEdges=numEdges;
n->hashCode=hashcode;
n->intAnnot[0]=0;n->intAnnot[1]=0;
}
}
}
+
+void convertPass(CNF *cnf, bool backtrackLit) {
+ uint numConstraints=getSizeVectorEdge(&cnf->constraints);
+ VectorEdge *ve=allocDefVectorEdge();
+ for(uint i=0; i<numConstraints;i++) {
+ convertConstraint(cnf, ve, getVectorEdge(&cnf->constraints, i), backtrackLit);
+ }
+ deleteVectorEdge(ve);
+}
+
+void convertConstraint(CNF *cnf, VectorEdge *stack, Edge root, bool backtrackLit) {
+ Node *nroot=getNodePtrFromEdge(root);
+
+ if (isNodeEdge(root) && (nroot->flags.type == NodeType_ITE || nroot->flags.type == NodeType_IFF)) {
+ root = (Edge) { (Node *) nroot->ptrAnnot[isNegEdge(root)]};
+ }
+
+ if (edgeIsConst(root)) {
+ if (isNegEdge(root)) {
+ //trivally unsat
+ Edge newvar=constraintNewVar(cnf);
+ Literal var=getEdgeVar(newvar);
+ Literal clause[] = {var, -var, 0};
+ addArrayClauseLiteral(cnf->solver, 3, clause);
+ return;
+ } else {
+ //trivially true
+ return;
+ }
+ } else if (edgeIsVarConst(root)) {
+ Literal clause[] = { getEdgeVar(root), 0};
+ addArrayClauseLiteral(cnf->solver, 2, clause);
+ return;
+ }
+
+ clearVectorEdge(stack);pushVectorEdge(stack, root);
+ while(getSizeVectorEdge(stack)!=0) {
+ Edge e=lastVectorEdge(stack);
+ Node *n=getNodePtrFromEdge(e);
+
+ if (edgeIsVarConst(e)) {
+ popVectorEdge(stack);
+ continue;
+ } else if (n->flags.type==NodeType_ITE ||
+ n->flags.type==NodeType_IFF) {
+ popVectorEdge(stack);
+ pushVectorEdge(stack, (Edge) {(Node *)n->ptrAnnot[0]});
+ pushVectorEdge(stack, (Edge) {(Node *)n->ptrAnnot[1]});
+ continue;
+ }
+
+ bool needPos = (n->intAnnot[0] > 0);
+ bool needNeg = (n->intAnnot[1] > 0);
+ if ((!needPos || n->flags.cnfVisitedUp & 1) ||
+ (!needNeg || n->flags.cnfVisitedUp & 2)) {
+ popVectorEdge(stack);
+ } else if ((needPos && !n->flags.cnfVisitedDown & 1) ||
+ (needNeg && !n->flags.cnfVisitedDown & 2)) {
+ if (needPos)
+ n->flags.cnfVisitedDown|=1;
+ if (needNeg)
+ n->flags.cnfVisitedDown|=2;
+ for(uint i=0; i<n->numEdges; i++) {
+ Edge arg=n->edges[i];
+ arg=constraintNegateIf(arg, isNegEdge(e));
+ pushVectorEdge(stack, arg); //WARNING, THIS LOOKS LIKE A BUG IN THE ORIGINAL CODE
+ }
+ } else {
+ popVectorEdge(stack);
+ produceCNF(cnf, e);
+ }
+ }
+ CNFExpr * cnfExp = (CNFExpr *) nroot->ptrAnnot[isNegEdge(root)];
+ if (isProxy(cnfExp)) {
+ //solver.add(getProxy(cnfExp))
+ } else if (backtrackLit) {
+ //solver.add(introProxy(solver, root, cnfExp, isNegEdge(root)));
+ } else {
+ //solver.add(*cnfExp);
+ }
+
+ if (!((intptr_t) cnfExp & 1)) {
+ //free rootExp
+ nroot->ptrAnnot[isNegEdge(root)] = NULL;
+ }
+}
+
+//DONE
+Literal introProxy(CNF * cnf, Edge e, CNFExpr* exp, bool isNeg) {
+ Literal l = 0;
+ Node * n = getNodePtrFromEdge(e);
+
+ if (n->flags.cnfVisitedUp & (1<<!isNeg)) {
+ CNFExpr* otherExp = (CNFExpr*) n->ptrAnnot[!isNeg];
+ if (isProxy(otherExp))
+ l = -getProxy(otherExp);
+ } else {
+ Edge semNeg={(Node *) n->ptrAnnot[isNeg]};
+ Node * nsemNeg=getNodePtrFromEdge(semNeg);
+ if (nsemNeg != NULL) {
+ if (nsemNeg->flags.cnfVisitedUp & (1 << isNeg)) {
+ CNFExpr* otherExp = (CNFExpr*) nsemNeg->ptrAnnot[isNeg];
+ if (isProxy(otherExp))
+ l = -getProxy(otherExp);
+ } else if (nsemNeg->flags.cnfVisitedUp & (1<< !isNeg)) {
+ CNFExpr* otherExp = (CNFExpr*) nsemNeg->ptrAnnot[!isNeg];
+ if (isProxy(otherExp))
+ l = getProxy(otherExp);
+ }
+ }
+ }
+
+ if (l == 0) {
+ Edge newvar = constraintNewVar(cnf);
+ l = getEdgeVar(newvar);
+ }
+ // Output the constraints on the auxiliary variable
+ constrainCNF(cnf, l, exp);
+ deleteCNFExpr(exp);
+
+ n->ptrAnnot[isNeg] = (void*) ((intptr_t) (l << 1) | 1);
+
+ return l;
+}
+
+//DONE
+void produceCNF(CNF * cnf, Edge e) {
+ CNFExpr* expPos = NULL;
+ CNFExpr* expNeg = NULL;
+ Node *n = getNodePtrFromEdge(e);
+
+ if (n->intAnnot[0] > 0) {
+ expPos = produceConjunction(cnf, e);
+ }
+
+ if (n->intAnnot[1] > 0) {
+ expNeg = produceDisjunction(cnf, e);
+ }
+
+ /// @todo Propagate constants across semantic negations (this can
+ /// be done similarly to the calls to propagate shown below). The
+ /// trick here is that we need to figure out how to get the
+ /// semantic negation pointers, and ensure that they can have CNF
+ /// produced for them at the right point
+ ///
+ /// propagate(solver, expPos, snPos, false) || propagate(solver, expNeg, snNeg, false)
+
+ // propagate from positive to negative, negative to positive
+ propagate(cnf, expPos, expNeg, true) || propagate(cnf, expNeg, expPos, true);
+
+ // The polarity heuristic entails visiting the discovery polarity first
+ if (isPosEdge(e)) {
+ saveCNF(cnf, expPos, e, false);
+ saveCNF(cnf, expNeg, e, true);
+ } else {
+ saveCNF(cnf, expNeg, e, true);
+ saveCNF(cnf, expPos, e, false);
+ }
+}
+
+
+//DONE
+bool propagate(CNF *cnf, CNFExpr * dest, CNFExpr * src, bool negate) {
+ if (src != NULL && !isProxy(src) && getLitSizeCNF(src) == 0) {
+ if (dest == NULL) {
+ dest = allocCNFExprBool(negate ? alwaysFalseCNF(src) : alwaysTrueCNF(src));
+ } else if (isProxy(dest)) {
+ bool alwaysTrue = (negate ? alwaysFalseCNF(src) : alwaysTrueCNF(src));
+ if (alwaysTrue) {
+ Literal clause[] = {getProxy(dest), 0};
+ addArrayClauseLiteral(cnf->solver, 2, clause);
+ } else {
+ Literal clause[] = {-getProxy(dest), 0};
+ addArrayClauseLiteral(cnf->solver, 2, clause);
+ }
+
+ dest = allocCNFExprBool(negate ? alwaysFalseCNF(src) : alwaysTrueCNF(src));
+ } else {
+ clearCNF(dest, negate ? alwaysFalseCNF(src) : alwaysTrueCNF(src));
+ }
+ return true;
+ }
+ return false;
+}
+
+void saveCNF(CNF *cnf, CNFExpr* exp, Edge e, bool sign) {
+ Node *n=getNodePtrFromEdge(e);
+ n->flags.cnfVisitedUp |= (1 << sign);
+ if (exp == NULL || isProxy(exp)) return;
+
+ if (exp->litSize == 1) {
+ Literal l = exp->singletons()[0];
+ deleteCNFExpr(exp);
+ n->ptrAnnot[sign] = (void*) ((intptr_t) (l << 1) | 1);
+ } else if (exp->litSize != 0 && (n->intAnnot[sign] > 1 || n->isVarForced())) {
+ introProxy(cnf, e, exp, sign);
+ } else {
+ n->ptrAnnot[sign] = exp;
+ }
+}
+
+void constrainCNF(CNF * cnf, Literal l, CNFExpr *exp) {
+ if (alwaysTrueCNF(exp)) {
+ return;
+ } else if (alwaysFalseCNF(exp)) {
+ Literal clause[] = {-l, 0};
+ addArrayClauseLiteral(cnf->solver, 2, clause);
+ return;
+ }
+ //FIXME
+
+}
+
+void outputCNF(CNF *cnf, CNFExpr *exp) {
+
+}
+
+CNFExpr* fillArgs(Edge e, bool isNeg, Edge * largestEdge, VectorEdge * args) {
+ args.clear();
+
+ *largestEdge = (void*) NULL;
+ CNFExpr* largest = NULL;
+ int i = e->size();
+ while (i != 0) {
+ Edge arg = (*e)[--i]; arg.negateIf(isNeg);
+ Node * narg = getNodePtrFromEdge(arg);
+
+ if (arg.isVar()) {
+ args.push(arg);
+ continue;
+ }
+
+ if (narg->flags.type == NodeType_ITE || narg->flags.type == NodeType_IFF) {
+ arg = (Edge) {(Node *) narg->ptrAnnot[isNegEdge(arg)]};
+ }
+
+ if (narg->intAnnot[isNegEdge(arg)] == 1) {
+ CNFExpr* argExp = (CNFExpr*) narg->ptrAnnot[isNegEdge(arg)];
+ if (!isProxy(argExp)) {
+ if (largest == NULL) {
+ largest = argExp;
+ * largestEdge = arg;
+ continue;
+ } else if (argExp->litSize > largest->litSize) {
+ args.push(* largestEdge);
+ largest = argExp;
+ * largestEdge = arg;
+ continue;
+ }
+ }
+ }
+ args.push(arg);
+ }
+
+ if (largest != NULL) {
+ largestEdge->ptrAnnot(isNegEdge(*largestEdge)) = NULL;
+ }
+
+ return largest;
+}
+
+
+CNFExpr * produceConjunction(CNF * cnf, Edge e) {
+ Edge largestEdge;
+ CNFExpr* accum = fillArgs(e, false, largestEdge);
+ if (accum == NULL) accum = allocCNFExprBool(true);
+
+ int i = _args.size();
+ while (i != 0) {
+ Edge arg(_args[--i]);
+ if (arg.isVar()) {
+ accum->conjoin(atomLit(arg));
+ } else {
+ CNFExpr* argExp = (CNFExpr*) arg->ptrAnnot(isNegEdge(arg));
+
+ bool destroy = (--arg->intAnnot(isNegEdge(arg)) == 0);
+ if (isProxy(argExp)) { // variable has been introduced
+ accum->conjoin(getProxy(argExp));
+ } else {
+ accum->conjoin(argExp, destroy);
+ if (destroy) arg->ptrAnnot(isNegEdge(arg)) = NULL;
+ }
+ }
+ }
+
+ return accum;
+}
+
+#define CLAUSE_MAX 3
+
+CNFExpr* produceDisjunction(CNF *cnf, Edge e) {
+ Edge largestEdge;
+ CNFExpr* accum = fillArgs(e, true, largestEdge);
+ if (accum == NULL)
+ accum = allocCNFExprBool(false);
+
+ // This is necessary to check to make sure that we don't start out
+ // with an accumulator that is "too large".
+
+ /// @todo Strictly speaking, introProxy doesn't *need* to free
+ /// memory, then this wouldn't have to reallocate CNFExpr
+
+ /// @todo When this call to introProxy is made, the semantic
+ /// negation pointer will have been destroyed. Thus, it will not
+ /// be possible to use the correct proxy. That should be fixed.
+
+ // at this point, we will either have NULL, or a destructible expression
+ if (accum->clauseSize() > CLAUSE_MAX)
+ accum = allocCNFExprLiteral(introProxy(cnf, largestEdge, accum, isNegEdge(largestEdge)));
+
+ int i = _args.size();
+ while (i != 0) {
+ Edge arg(_args[--i]);
+ Node *narg=getNodePtrFromEdge(arg);
+ if (arg.isVar()) {
+ accum->disjoin(atomLit(arg));
+ } else {
+ CNFExpr* argExp = (CNFExpr*) narg->ptrAnnot[isNegEdge(arg)];
+
+ bool destroy = (--narg->intAnnot[isNegEdge(arg)] == 0);
+ if (isProxy(argExp)) { // variable has been introduced
+ accum->disjoin(getProxy(argExp));
+ } else if (argExp->litSize == 0) {
+ accum->disjoin(argExp, destroy);
+ } else {
+ // check to see if we should introduce a proxy
+ int aL = accum->litSize; // lits in accum
+ int eL = argExp->litSize; // lits in argument
+ int aC = getClauseSizeCNF(accum); // clauses in accum
+ int eC = getClauseSizeCNF(argExp); // clauses in argument
+
+ if (eC > CLAUSE_MAX || (eL * aC + aL * eC > eL + aC + aL + aC)) {
+ accum->disjoin(introProxy(cnf, arg, argExp, isNegEdge(arg)));
+ } else {
+ accum->disjoin(argExp, destroy);
+ if (destroy) narg->ptrAnnot[isNegEdge(arg)] = NULL;
+ }
+ }
+ }
+ }
+
+ return accum;
+}
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