isl_lp.c

   1 #include "isl_ctx.h"
   2 #include "isl_lp.h"
   3 #include "isl_lp_piplib.h"
   4 #include "isl_tab.h"
   5 #include "isl_map_private.h"
   6
   7 enum isl_lp_result isl_tab_solve_lp(struct isl_basic_map *bmap, int maximize,
   8                                       isl_int *f, isl_int denom, isl_int *opt,
   9                                       isl_int *opt_denom)
  10 {
  11         struct isl_tab *tab;
  12         enum isl_lp_result res;
  13         unsigned dim = isl_basic_map_total_dim(bmap);
  14
  15         if (maximize)
  16                 isl_seq_neg(f, f, 1 + dim);
  17
  18         bmap = isl_basic_map_gauss(bmap, NULL);
  19         tab = isl_tab_from_basic_map(bmap);
  20         res = isl_tab_min(tab, f, bmap->ctx->one, opt, opt_denom, 0);
  21         isl_tab_free(tab);
  22
  23         if (maximize)
  24                 isl_seq_neg(f, f, 1 + dim);
  25
  26         return res;
  27 }
  28
  29 /* Given a basic map "bmap" and an affine combination of the variables "f"
  30  * with denominator "denom", set *opt/*opt_denom to the minimal
  31  * (or maximal if "maximize" is true) value attained by f/d over "bmap",
  32  * assuming the basic map is not empty and the expression cannot attain
  33  * arbitrarily small (or large) values.
  34  * If opt_denom is NULL, then *opt is rounded up (or down)
  35  * to the nearest integer.
  36  * The return value reflects the nature of the result (empty, unbounded,
  37  * minmimal or maximal value returned in *opt).
  38  */
  39 enum isl_lp_result isl_solve_lp(struct isl_basic_map *bmap, int maximize,
  40                                       isl_int *f, isl_int d, isl_int *opt,
  41                                       isl_int *opt_denom)
  42 {
  43         if (!bmap)
  44                 return isl_lp_error;
  45
  46         switch (bmap->ctx->lp_solver) {
  47         case ISL_LP_PIP:
  48                 return isl_pip_solve_lp(bmap, maximize, f, d, opt, opt_denom);
  49         case ISL_LP_TAB:
  50                 return isl_tab_solve_lp(bmap, maximize, f, d, opt, opt_denom);
  51         default:
  52                 return isl_lp_error;
  53         }
  54 }