src/Backend/satencoder.cc

   1 #include "satencoder.h"
   2 #include "structs.h"
   3 #include "csolver.h"
   4 #include "boolean.h"
   5 #include "constraint.h"
   6 #include "common.h"
   7 #include "element.h"
   8 #include "function.h"
   9 #include "tableentry.h"
  10 #include "table.h"
  11 #include "order.h"
  12 #include "predicate.h"
  13 #include "set.h"
  14
  15 SATEncoder::SATEncoder(CSolver *_solver) :
  16         cnf(createCNF()),
  17         solver(_solver),
  18   vector(allocDefVectorEdge()) {
  19 }
  20
  21 SATEncoder::~SATEncoder() {
  22         deleteCNF(cnf);
  23         deleteVectorEdge(vector);
  24 }
  25
  26 void SATEncoder::resetSATEncoder() {
  27         resetCNF(cnf);
  28         booledgeMap.reset();
  29 }
  30
  31 int SATEncoder::solve() {
  32         return solveCNF(cnf);
  33 }
  34
  35 void SATEncoder::encodeAllSATEncoder(CSolver *csolver) {
  36         SetIteratorBooleanEdge *iterator = csolver->getConstraints();
  37         while (iterator->hasNext()) {
  38                 BooleanEdge constraint = iterator->next();
  39                 Edge c = encodeConstraintSATEncoder(constraint);
  40                 addConstraintCNF(cnf, c);
  41         }
  42         delete iterator;
  43 }
  44
  45 Edge SATEncoder::encodeConstraintSATEncoder(BooleanEdge c) {
  46         Edge result;
  47         Boolean *constraint = c.getBoolean();
  48
  49         if (booledgeMap.contains(constraint)) {
  50                 Edge e = {(Node *) booledgeMap.get(constraint)};
  51                 return c.isNegated() ? constraintNegate(e) : e;
  52         }
  53
  54         switch (constraint->type) {
  55         case ORDERCONST:
  56                 result = encodeOrderSATEncoder((BooleanOrder *) constraint);
  57                 break;
  58         case BOOLEANVAR:
  59                 result = encodeVarSATEncoder((BooleanVar *) constraint);
  60                 break;
  61         case LOGICOP:
  62                 result = encodeLogicSATEncoder((BooleanLogic *) constraint);
  63                 break;
  64         case PREDICATEOP:
  65                 result = encodePredicateSATEncoder((BooleanPredicate *) constraint);
  66                 break;
  67         default:
  68                 model_print("Unhandled case in encodeConstraintSATEncoder %u", constraint->type);
  69                 exit(-1);
  70         }
  71         Polarity p = constraint->polarity;
  72         uint pSize = constraint->parents.getSize();
  73         if ((pSize > 1 && p != P_BOTHTRUEFALSE ) || pSize > 2) {
  74                 Edge e = getNewVarSATEncoder();
  75                 generateProxy(cnf, result, e, p);
  76                 booledgeMap.put(constraint, e.node_ptr);
  77                 result = e;
  78         }
  79
  80         return c.isNegated() ? constraintNegate(result) : result;
  81 }
  82
  83 void SATEncoder::getArrayNewVarsSATEncoder(uint num, Edge *carray) {
  84         for (uint i = 0; i < num; i++)
  85                 carray[i] = getNewVarSATEncoder();
  86 }
  87
  88 Edge SATEncoder::getNewVarSATEncoder() {
  89         return constraintNewVar(cnf);
  90 }
  91
  92 Edge SATEncoder::encodeVarSATEncoder(BooleanVar *constraint) {
  93         if (edgeIsNull(constraint->var)) {
  94                 constraint->var = getNewVarSATEncoder();
  95         }
  96         return constraint->var;
  97 }
  98
  99 Edge SATEncoder::encodeLogicSATEncoder(BooleanLogic *constraint) {
 100         Edge array[constraint->inputs.getSize()];
 101         for (uint i = 0; i < constraint->inputs.getSize(); i++)
 102                 array[i] = encodeConstraintSATEncoder(constraint->inputs.get(i));
 103
 104         switch (constraint->op) {
 105         case SATC_AND:
 106                 return constraintAND(cnf, constraint->inputs.getSize(), array);
 107         case SATC_NOT:
 108                 return constraintNegate(array[0]);
 109         case SATC_IFF:
 110                 ASSERT(constraint->inputs.getSize() == 2);
 111                 return constraintIFF(cnf, array[0], array[1]);
 112         case SATC_OR:
 113         case SATC_XOR:
 114         case SATC_IMPLIES:
 115         //Don't handle, translate these away...
 116         default:
 117                 model_print("Unhandled case in encodeLogicSATEncoder %u", constraint->op);
 118                 exit(-1);
 119         }
 120 }
 121
 122 Edge SATEncoder::encodePredicateSATEncoder(BooleanPredicate *constraint) {
 123         switch (constraint->predicate->type) {
 124         case TABLEPRED:
 125                 return encodeTablePredicateSATEncoder(constraint);
 126         case OPERATORPRED:
 127                 return encodeOperatorPredicateSATEncoder(constraint);
 128         default:
 129                 ASSERT(0);
 130         }
 131         return E_BOGUS;
 132 }
 133
 134 Edge SATEncoder::encodeTablePredicateSATEncoder(BooleanPredicate *constraint) {
 135         switch (constraint->encoding.type) {
 136         case ENUMERATEIMPLICATIONS:
 137         case ENUMERATEIMPLICATIONSNEGATE:
 138                 return encodeEnumTablePredicateSATEncoder(constraint);
 139         case CIRCUIT:
 140                 ASSERT(0);
 141                 break;
 142         default:
 143                 ASSERT(0);
 144         }
 145         return E_BOGUS;
 146 }
 147
 148 void SATEncoder::encodeElementSATEncoder(Element *element) {
 149         /* Check to see if we have already encoded this element. */
 150         if (element->getElementEncoding()->variables != NULL)
 151                 return;
 152
 153         /* Need to encode. */
 154         switch ( element->type) {
 155         case ELEMFUNCRETURN:
 156                 generateElementEncoding(element);
 157                 encodeElementFunctionSATEncoder((ElementFunction *) element);
 158                 break;
 159         case ELEMSET:
 160                 generateElementEncoding(element);
 161                 return;
 162         case ELEMCONST:
 163                 return;
 164         default:
 165                 ASSERT(0);
 166         }
 167 }
 168
 169 void SATEncoder::encodeElementFunctionSATEncoder(ElementFunction *function) {
 170         switch (function->getFunction()->type) {
 171         case TABLEFUNC:
 172                 encodeTableElementFunctionSATEncoder(function);
 173                 break;
 174         case OPERATORFUNC:
 175                 encodeOperatorElementFunctionSATEncoder(function);
 176                 break;
 177         default:
 178                 ASSERT(0);
 179         }
 180 }
 181
 182 void SATEncoder::encodeTableElementFunctionSATEncoder(ElementFunction *function) {
 183         switch (function->getElementFunctionEncoding()->type) {
 184         case ENUMERATEIMPLICATIONS:
 185                 encodeEnumTableElemFunctionSATEncoder(function);
 186                 break;
 187         case CIRCUIT:
 188                 ASSERT(0);
 189                 break;
 190         default:
 191                 ASSERT(0);
 192         }
 193 }