polysign_polylib.c

   1 #include <barvinok/util.h>
   2 #include "polysign.h"
   3
   4 static enum order_sign interval_minmax(Polyhedron *I)
   5 {
   6     int i;
   7     int min = 1;
   8     int max = -1;
   9     assert(I->Dimension == 1);
  10     POL_ENSURE_VERTICES(I);
  11     for (i = 0; i < I->NbRays; ++i) {
  12         if (value_pos_p(I->Ray[i][1]))
  13             max = 1;
  14         else if (value_neg_p(I->Ray[i][1]))
  15             min = -1;
  16         else {
  17             if (max < 0)
  18                 max = 0;
  19             if (min > 0)
  20                 min = 0;
  21         }
  22     }
  23     if (min > 0)
  24         return order_gt;
  25     if (max < 0)
  26         return order_lt;
  27     if (min == max)
  28         return order_eq;
  29     if (max == 0)
  30         return order_le;
  31     if (min == 0)
  32         return order_ge;
  33     return order_unknown;
  34 }
  35
  36 /* Returns the sign of the affine function specified by T on the polyhedron D */
  37 enum order_sign PL_polyhedron_affine_sign(Polyhedron *D, Matrix *T,
  38                                             struct barvinok_options *options)
  39 {
  40     enum order_sign sign;
  41     Polyhedron *I = Polyhedron_Image(D, T, options->MaxRays);
  42     if (POL_ISSET(options->MaxRays, POL_INTEGER))
  43         I = DomainConstraintSimplify(I, options->MaxRays);
  44     if (emptyQ2(I)) {
  45         Polyhedron_Free(I);
  46         I = Polyhedron_Image(D, T, options->MaxRays);
  47     }
  48     sign = interval_minmax(I);
  49     Polyhedron_Free(I);
  50     return sign;
  51 }