reduce_domain.c

   1 #include "reduce_domain.h"
   2
   3 Polyhedron *reduce_domain(Polyhedron *D, Matrix *CT, Polyhedron *CEq,
   4                           Polyhedron **fVD, int nd, unsigned MaxRays)
   5 {
   6     Polyhedron *Dt, *rVD;
   7     Value c;
   8     int i;
   9
  10     Dt = CT ? DomainPreimage(D, CT, MaxRays) : D;
  11     rVD = CEq ? DomainIntersection(Dt, CEq, MaxRays) : Domain_Copy(Dt);
  12
  13     /* if rVD is empty or too small in geometric dimension */
  14     if(!rVD || emptyQ(rVD) ||
  15             (CEq && rVD->Dimension-rVD->NbEq < Dt->Dimension-Dt->NbEq-CEq->NbEq)) {
  16         if(rVD)
  17             Domain_Free(rVD);
  18         if (CT)
  19             Domain_Free(Dt);
  20         return 0;               /* empty validity domain */
  21     }
  22
  23     if (CT)
  24         Domain_Free(Dt);
  25
  26     fVD[nd] = Domain_Copy(rVD);
  27     for (i = 0 ; i < nd; ++i) {
  28         Polyhedron *F;
  29         Polyhedron *I = DomainIntersection(fVD[nd], fVD[i], MaxRays);
  30         if (emptyQ(I)) {
  31             Domain_Free(I);
  32             continue;
  33         }
  34         F = DomainSimplify(I, fVD[nd], MaxRays);
  35         if (F->NbEq == 1) {
  36             Polyhedron *T = rVD;
  37             rVD = DomainDifference(rVD, F, MaxRays);
  38             Domain_Free(T);
  39         }
  40         Domain_Free(F);
  41         Domain_Free(I);
  42     }
  43
  44     rVD = DomainConstraintSimplify(rVD, MaxRays);
  45     if (emptyQ(rVD)) {
  46         Domain_Free(fVD[nd]);
  47         Domain_Free(rVD);
  48         return 0;
  49     }
  50
  51     value_init(c);
  52     barvinok_count(rVD, &c, MaxRays);
  53     if (value_zero_p(c)) {
  54         Domain_Free(rVD);
  55         rVD = 0;
  56     }
  57     value_clear(c);
  58
  59     return rVD;
  60 }