From af438dfdfbb57c13203b8ed196241a5c95aa6215 Mon Sep 17 00:00:00 2001
From: bdemsky <bdemsky@uci.edu>
Date: Fri, 7 Jul 2017 20:26:20 -0700
Subject: [PATCH] more edits
---
src/Backend/cnfexpr.c | 81 +++++++++
src/Backend/cnfexpr.h | 32 ++++
src/Backend/constraint.h | 3 +
src/Backend/inc_solver.c | 9 +
src/Backend/inc_solver.h | 1 +
src/Backend/nodeedge.c | 346 +++++++++++++++++++++++++++++++++++++++
src/Backend/nodeedge.h | 26 +++
7 files changed, 498 insertions(+)
create mode 100644 src/Backend/cnfexpr.c
create mode 100644 src/Backend/cnfexpr.h
diff --git a/src/Backend/cnfexpr.c b/src/Backend/cnfexpr.c
new file mode 100644
index 0000000..02fdeb1
--- /dev/null
+++ b/src/Backend/cnfexpr.c
@@ -0,0 +1,81 @@
+#include "cnfexpr.h"
+
+#define LITCAPACITY 4
+#define MERGESIZE 5
+
+static inline uint boundedSize(uint x) { return (x > MERGESIZE)?MERGESIZE:x; }
+
+LitVector * allocLitVector() {
+ LitVector *This=ourmalloc(sizeofLitVector);
+ initLitVector(This);
+ return This;
+}
+
+void initLitVector(LitVector *This) {
+ This->size=0;
+ This->capacity=LITCAPACITY;
+ This->literals=ourmalloc(This->capacity * sizeof(Literal));
+}
+
+void freeLitVector(LitVector *This) {
+ ourfree(This->literals);
+}
+
+void deleteLitVector(LitVector *This) {
+ freeLitVector(This);
+ ourfree(This);
+}
+
+void addLiteralLitVector(LitVector *This, Literal l) {
+ Literal labs = abs(l);
+ uint vec_size=This->size;
+ uint searchsize=boundedSize(vec_size);
+ uint i=0;
+ for (; i < searchsize; i++) {
+ Literal curr = This->literals[i];
+ Literals currabs = abs(curr);
+ if (currabs > labs)
+ break;
+ if (currabs == labs) {
+ if (curr == -l)
+ size = 0; //either true or false now depending on whether this is a conj or disj
+ return;
+ }
+ if ((++This->size) >= This->capacity) {
+ This->capacity << = 1;
+ This->literals=ourrealloc(This->capacity * sizeof(Literal));
+ }
+
+ if (vec_size < MERGESIZE) {
+ memmove(&This->literals[i+1], &This->literals[i], (vec_size-i) * sizeof(Literal));
+ This->literals[i]=l;
+ } else {
+ This->literals[vec_size]=l;
+ }
+ }
+}
+
+CNFExpr * allocCNFExprBool(bool isTrue) {
+ CNFExpr *This=ourmalloc(sizeof(CNFExpr));
+ this->litSize=0;
+ this->isTrue=isTrue;
+ allocInlineVectorLitVector(&This->clauses);
+ initLitVector(&This->singletons);
+ return This;
+}
+
+CNFExpr * allocCNFExprLiteral(Literal l) {
+ CNFExpr *This=ourmalloc(sizeof(CNFExpr));
+ this->litSize=1;
+ this->isTrue=false;
+ allocInlineVectorLitVector(&This->clauses);
+ initLitVector(&This->singletons);
+ addLiteralLitVector(This, l);
+ return This;
+}
+
+void deleteCNFExpr(CNFExpr *This) {
+ deleteVectorArray(&This->clauses);
+ freeLitVector(&This->singletons);
+ ourfree(This);
+}
diff --git a/src/Backend/cnfexpr.h b/src/Backend/cnfexpr.h
new file mode 100644
index 0000000..fcb75bd
--- /dev/null
+++ b/src/Backend/cnfexpr.h
@@ -0,0 +1,32 @@
+#ifndef CNFEXPR_H
+#define CNFEXPR_H
+#include "classlist.h"
+#include "vector.h"
+
+typedef int Literal;
+
+
+struct LitVector {
+ uint size;
+ uint capacity;
+ Literal *literals;
+};
+typedef CNFClause CNFClause;
+
+VectorDef(LitVector, LitVector *)
+
+struct CNFExpr {
+ uint litSize;
+ bool isTrue;
+ VectorLitVector clauses;
+ LitVector singletons;
+};
+
+typedef CNFExpr CNFExpr;
+
+bool alwaysTrueCNF(CNFExpr * This);
+bool alwaysFalseCNF(CNFExpr * This);
+uint getLitSizeCNF(CNFExpr * This);
+void clearCNF(CNFExpr *This, bool isTrue);
+uint getClauseSizeCNF(CNFExpr * This);
+#endif
diff --git a/src/Backend/constraint.h b/src/Backend/constraint.h
index e1b21d3..0d254c8 100644
--- a/src/Backend/constraint.h
+++ b/src/Backend/constraint.h
@@ -44,6 +44,7 @@ Constraint * cloneConstraint(Constraint * c);
static inline void setNegConstraint(Constraint * This, Constraint *c) {This->neg=c;}
Constraint *negateConstraint(Constraint * c);
+
extern Constraint ctrue;
extern Constraint cfalse;
@@ -51,4 +52,6 @@ Constraint * generateBinaryConstraint(uint numvars, Constraint ** vars, uint val
Constraint * generateLTConstraint(uint numvars, Constraint ** vars, uint value);
Constraint * generateEquivNVConstraint(uint numvars, Constraint **var1, Constraint **var2);
Constraint * generateEquivConstraint(Constraint *var1, Constraint *var2);
+
+
#endif
diff --git a/src/Backend/inc_solver.c b/src/Backend/inc_solver.c
index 5e1ed54..b9cc549 100644
--- a/src/Backend/inc_solver.c
+++ b/src/Backend/inc_solver.c
@@ -42,6 +42,15 @@ void addClauseLiteral(IncrementalSolver * This, int literal) {
}
}
+void addArrayClauseLiteral(IncrementalSolver * This, uint numliterals, int * literals) {
+ for(uint i=0;i<numliterals; i++) {
+ This->buffer[This->offset++]=literals[i];
+ if (This->offset==IS_BUFFERSIZE) {
+ flushBufferSolver(This);
+ }
+ }
+}
+
void finishedClauses(IncrementalSolver * This) {
addClauseLiteral(This, 0);
}
diff --git a/src/Backend/inc_solver.h b/src/Backend/inc_solver.h
index 15e5def..9b3e2ab 100644
--- a/src/Backend/inc_solver.h
+++ b/src/Backend/inc_solver.h
@@ -31,6 +31,7 @@ struct IncrementalSolver {
IncrementalSolver * allocIncrementalSolver();
void deleteIncrementalSolver(IncrementalSolver * This);
void addClauseLiteral(IncrementalSolver * This, int literal);
+void addArrayClauseLiteral(IncrementalSolver * This, uint numliterals, int * literals);
void finishedClauses(IncrementalSolver * This);
void freeze(IncrementalSolver * This, int variable);
int solve(IncrementalSolver * This);
diff --git a/src/Backend/nodeedge.c b/src/Backend/nodeedge.c
index c244754..4a3719b 100644
--- a/src/Backend/nodeedge.c
+++ b/src/Backend/nodeedge.c
@@ -1,6 +1,9 @@
#include "nodeedge.h"
#include <string.h>
#include <stdlib.h>
+#include "inc_solver.h"
+
+/** Code ported from C++ BAT implementation of NICE-SAT */
VectorImpl(Edge, Edge, 16)
@@ -56,6 +59,8 @@ Node * allocNode(NodeType type, uint numEdges, Edge * edges, uint hashcode) {
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;
@@ -339,3 +344,344 @@ void countConstraint(CNF *cnf, VectorEdge *stack, Edge e) {
}
}
}
+
+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);
+ //delete exp; //FIXME
+
+ 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];
+ delete exp;
+ n->ptrAnnot[sign] = (void*) ((intptr_t) (l << 1) | 1);
+ } else if (exp->litSize != 0 && (n->intAnnot[sign] > 1 || e->isVarForced())) {
+ introProxy(solver, e, exp, sign);
+ } else {
+ n->ptrAnnot[sign] = exp;
+ }
+}
+
+void constrainCNF(CNF * cnf, Literal l, CNFExpr *exp) {
+ if (alwaysTrueCNF(exp)) {
+ return;
+ } else if (alwaysFalseCNF(expr)) {
+ Literal clause[] = {-l, 0};
+ addArrayClauseLiteral(cnf->solver, 2, clause);
+ return;
+ }
+ //FIXME
+
+}
+
+void outputCNF(CNF *cnf, CNFExpr *exp) {
+
+}
+
+CNFExpr* fillArgs(CNF *cnf, Edge e, bool isNeg, Edge * largestEdge, VectorEdge * args) {
+ args.clear();
+
+ *largestEdge = (void*) NULL;
+ CnfExp* largest = NULL;
+ int i = e->size();
+ while (i != 0) {
+ Edge arg = (*e)[--i]; arg.negateIf(isNeg);
+
+ if (arg.isVar()) {
+ args.push(arg);
+ continue;
+ }
+
+ if (arg->op() == NodeOp_Ite || arg->op() == NodeOp_Iff) {
+ arg = arg->ptrAnnot(arg.isNeg());
+ }
+
+ if (arg->intAnnot(arg.isNeg()) == 1) {
+ CnfExp* argExp = (CnfExp*) arg->ptrAnnot(arg.isNeg());
+ 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(largestEdge.isNeg()) = NULL;
+ }
+
+ return largest;
+}
+
+
+CNFExpr * produceConjunction(CNF * cnf, Edge e) {
+ Edge largestEdge;
+ CnfExp* accum = fillArgs(e, false, largestEdge);
+ if (accum == NULL) accum = new CnfExp(true);
+
+ int i = _args.size();
+ while (i != 0) {
+ Edge arg(_args[--i]);
+ if (arg.isVar()) {
+ accum->conjoin(atomLit(arg));
+ } else {
+ CnfExp* argExp = (CnfExp*) arg->ptrAnnot(arg.isNeg());
+
+ bool destroy = (--arg->intAnnot(arg.isNeg()) == 0);
+ if (isProxy(argExp)) { // variable has been introduced
+ accum->conjoin(getProxy(argExp));
+ } else {
+ accum->conjoin(argExp, destroy);
+ if (destroy) arg->ptrAnnot(arg.isNeg()) = 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 = new CNFExpr(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 = new CNFExpr(introProxy(solver, largestEdge, accum, largestEdge.isNeg()));
+
+ int i = _args.size();
+ while (i != 0) {
+ Edge arg(_args[--i]);
+ if (arg.isVar()) {
+ accum->disjoin(atomLit(arg));
+ } else {
+ CNFExpr* argExp = (CNFExpr*) arg->ptrAnnot(arg.isNeg());
+
+ bool destroy = (--arg->intAnnot(arg.isNeg()) == 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(solver, arg, argExp, arg.isNeg()));
+ } else {
+ accum->disjoin(argExp, destroy);
+ if (destroy) arg->ptrAnnot(arg.isNeg()) = NULL;
+ }
+ }
+ }
+ }
+
+ return accum;
+}
diff --git a/src/Backend/nodeedge.h b/src/Backend/nodeedge.h
index e17bba6..e515640 100644
--- a/src/Backend/nodeedge.h
+++ b/src/Backend/nodeedge.h
@@ -31,6 +31,8 @@ typedef enum NodeType NodeType;
struct NodeFlags {
NodeType type:2;
int wasExpanded:2;
+ int cnfVisitedDown:2;
+ int cnfVisitedUp:2;
};
typedef struct NodeFlags NodeFlags;
@@ -55,11 +57,15 @@ struct CNF {
uint maxsize;
bool enableMatching;
Node ** node_array;
+ IncrementalSolver * solver;
VectorEdge constraints;
};
typedef struct CNF CNF;
+struct CNFExpr;
+typedef struct CNFExpr CNFExpr;
+
static inline bool getExpanded(Node *n, int isNegated) {
return n->flags.wasExpanded & (1<<isNegated);
}
@@ -89,6 +95,10 @@ static inline bool isNegEdge(Edge e) {
return ((uintptr_t)e.node_ptr) & NEGATE_EDGE;
}
+static inline bool isPosEdge(Edge e) {
+ return !(((uintptr_t)e.node_ptr) & NEGATE_EDGE);
+}
+
static inline bool isNodeEdge(Edge e) {
return !(((uintptr_t)e.node_ptr) & EDGE_IS_VAR_CONSTANT);
}
@@ -142,6 +152,18 @@ static inline Edge constraintNegateIf(Edge e, bool negate) {
return eret;
}
+static inline Literal getEdgeVar(Edge e) {
+ int val = (int) (((uintptr_t) e.node_ptr) >> VAR_SHIFT);
+ return isNegEdge(e) ? -val : val;
+}
+
+static inline bool isProxy(CNFExpr *expr) {
+ return (bool) (((intptr_t) expr) & 1);
+}
+
+static inline Literal getProxy(CNFExpr *expr) {
+ return (Literal) (((intptr_t) expr) >> 1);
+}
uint hashNode(NodeType type, uint numEdges, Edge * edges);
Node * allocNode(NodeType type, uint numEdges, Edge * edges, uint hashCode);
@@ -157,6 +179,10 @@ Edge constraintITE(CNF * cnf, Edge cond, Edge thenedge, Edge elseedge);
Edge constraintNewVar(CNF *cnf);
void countPass(CNF *cnf);
void countConstraint(CNF *cnf, VectorEdge * stack, Edge e);
+void convertPass(CNF *cnf, bool backtrackLit);
+void convertConstraint(CNF *cnf, VectorEdge *stack, Edge e, bool backtrackLit);
+void constrain(CNF * cnf, Literal l, CNFExpr *exp);
+void produceCNF(CNF * cnf, Edge e);
Edge E_True={(Node *)(uintptr_t) EDGE_IS_VAR_CONSTANT};
--
2.34.1