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 #include "tunable.h"
  15
  16 SATEncoder::SATEncoder(CSolver *_solver) :
  17         cnf(createCNF()),
  18         solver(_solver),
  19         vector(allocDefVectorEdge()) {
  20 }
  21
  22 SATEncoder::~SATEncoder() {
  23         deleteCNF(cnf);
  24         deleteVectorEdge(vector);
  25 }
  26
  27 void SATEncoder::resetSATEncoder() {
  28         resetCNF(cnf);
  29         booledgeMap.reset();
  30 }
  31
  32 int SATEncoder::solve() {
  33         return solveCNF(cnf);
  34 }
  35
  36 void SATEncoder::encodeAllSATEncoder(CSolver *csolver) {
  37         SetIteratorBooleanEdge *iterator = csolver->getConstraints();
  38         while (iterator->hasNext()) {
  39                 BooleanEdge constraint = iterator->next();
  40                 Edge c = encodeConstraintSATEncoder(constraint);
  41                 addConstraintCNF(cnf, c);
  42         }
  43         delete iterator;
  44 }
  45
  46 Edge SATEncoder::encodeConstraintSATEncoder(BooleanEdge c) {
  47         Edge result;
  48         Boolean *constraint = c.getBoolean();
  49
  50         if (booledgeMap.contains(constraint)) {
  51                 Edge e = {(Node *) booledgeMap.get(constraint)};
  52                 return c.isNegated() ? constraintNegate(e) : e;
  53         }
  54
  55         switch (constraint->type) {
  56         case ORDERCONST:
  57                 result = encodeOrderSATEncoder((BooleanOrder *) constraint);
  58                 break;
  59         case BOOLEANVAR:
  60                 result = encodeVarSATEncoder((BooleanVar *) constraint);
  61                 break;
  62         case LOGICOP:
  63                 result = encodeLogicSATEncoder((BooleanLogic *) constraint);
  64                 break;
  65         case PREDICATEOP:
  66                 result = encodePredicateSATEncoder((BooleanPredicate *) constraint);
  67                 break;
  68         case BOOLCONST:
  69                 result = ((BooleanConst *) constraint)->isTrue() ? E_True : E_False;
  70                 break;
  71         default:
  72                 model_print("Unhandled case in encodeConstraintSATEncoder %u", constraint->type);
  73                 exit(-1);
  74         }
  75         Polarity p = constraint->polarity;
  76         uint pSize = constraint->parents.getSize();
  77
  78         if ( !edgeIsVarConst(result) && pSize > (uint)solver->getTuner()->getTunable(PROXYVARIABLE, &proxyparameter) ) {
  79                 Edge e = getNewVarSATEncoder();
  80                 generateProxy(cnf, result, e, p);
  81                 booledgeMap.put(constraint, e.node_ptr);
  82                 result = e;
  83         }
  84
  85         return c.isNegated() ? constraintNegate(result) : result;
  86 }
  87
  88 void SATEncoder::getArrayNewVarsSATEncoder(uint num, Edge *carray) {
  89         for (uint i = 0; i < num; i++)
  90                 carray[i] = getNewVarSATEncoder();
  91 }
  92
  93 Edge SATEncoder::getNewVarSATEncoder() {
  94         return constraintNewVar(cnf);
  95 }
  96
  97 Edge SATEncoder::encodeVarSATEncoder(BooleanVar *constraint) {
  98         if (edgeIsNull(constraint->var)) {
  99                 constraint->var = getNewVarSATEncoder();
 100         }
 101         return constraint->var;
 102 }
 103
 104 Edge SATEncoder::encodeLogicSATEncoder(BooleanLogic *constraint) {
 105         Edge array[constraint->inputs.getSize()];
 106         for (uint i = 0; i < constraint->inputs.getSize(); i++)
 107                 array[i] = encodeConstraintSATEncoder(constraint->inputs.get(i));
 108
 109         switch (constraint->op) {
 110         case SATC_AND:
 111                 return constraintAND(cnf, constraint->inputs.getSize(), array);
 112         case SATC_NOT:
 113                 return constraintNegate(array[0]);
 114         case SATC_IFF:
 115                 ASSERT(constraint->inputs.getSize() == 2);
 116                 return constraintIFF(cnf, array[0], array[1]);
 117         case SATC_OR:
 118         case SATC_XOR:
 119         case SATC_IMPLIES:
 120         //Don't handle, translate these away...
 121         default:
 122                 model_print("Unhandled case in encodeLogicSATEncoder %u", constraint->op);
 123                 exit(-1);
 124         }
 125 }
 126
 127 Edge SATEncoder::encodePredicateSATEncoder(BooleanPredicate *constraint) {
 128         switch (constraint->predicate->type) {
 129         case TABLEPRED:
 130                 return encodeTablePredicateSATEncoder(constraint);
 131         case OPERATORPRED:
 132                 return encodeOperatorPredicateSATEncoder(constraint);
 133         default:
 134                 ASSERT(0);
 135         }
 136         return E_BOGUS;
 137 }
 138
 139 Edge SATEncoder::encodeTablePredicateSATEncoder(BooleanPredicate *constraint) {
 140         switch (constraint->encoding.type) {
 141         case ENUMERATEIMPLICATIONS:
 142         case ENUMERATEIMPLICATIONSNEGATE:
 143                 return encodeEnumTablePredicateSATEncoder(constraint);
 144         case CIRCUIT:
 145                 ASSERT(0);
 146                 break;
 147         default:
 148                 ASSERT(0);
 149         }
 150         return E_BOGUS;
 151 }
 152
 153 void SATEncoder::encodeElementSATEncoder(Element *element) {
 154         /* Check to see if we have already encoded this element. */
 155         if (element->getElementEncoding()->variables != NULL)
 156                 return;
 157
 158         /* Need to encode. */
 159         switch ( element->type) {
 160         case ELEMFUNCRETURN:
 161                 generateElementEncoding(element);
 162                 encodeElementFunctionSATEncoder((ElementFunction *) element);
 163                 break;
 164         case ELEMSET:
 165                 generateElementEncoding(element);
 166                 return;
 167         case ELEMCONST:
 168                 return;
 169         default:
 170                 ASSERT(0);
 171         }
 172 }
 173
 174 void SATEncoder::encodeElementFunctionSATEncoder(ElementFunction *function) {
 175         switch (function->getFunction()->type) {
 176         case TABLEFUNC:
 177                 encodeTableElementFunctionSATEncoder(function);
 178                 break;
 179         case OPERATORFUNC:
 180                 encodeOperatorElementFunctionSATEncoder(function);
 181                 break;
 182         default:
 183                 ASSERT(0);
 184         }
 185 }
 186
 187 void SATEncoder::encodeTableElementFunctionSATEncoder(ElementFunction *function) {
 188         switch (function->getElementFunctionEncoding()->type) {
 189         case ENUMERATEIMPLICATIONS:
 190                 encodeEnumTableElemFunctionSATEncoder(function);
 191                 break;
 192         case CIRCUIT:
 193                 ASSERT(0);
 194                 break;
 195         default:
 196                 ASSERT(0);
 197         }
 198 }