polysign_isl.c

   1 #include <assert.h>
   2 #include <isl/val_gmp.h>
   3 #include <isl/lp.h>
   4 #include <isl_set_polylib.h>
   5 #include "polysign.h"
   6
   7 static void values2isl(Value *src, isl_int *dst, int len)
   8 {
   9         int i;
  10
  11         for (i = 0; i < len; ++i)
  12                 isl_int_set_gmp(dst[i], src[i]);
  13 }
  14
  15 static __isl_give isl_mat *extract_equalities(isl_ctx *ctx, Matrix *M)
  16 {
  17         int i, j;
  18         int n;
  19         isl_val *v;
  20         isl_mat *eq;
  21
  22         n = 0;
  23         for (i = 0; i < M->NbRows; ++i)
  24                 if (value_zero_p(M->p[i][0]))
  25                         ++n;
  26
  27         eq = isl_mat_alloc(ctx, n, M->NbColumns - 1);
  28         for (i = 0; i < M->NbRows; ++i) {
  29                 if (!value_zero_p(M->p[i][0]))
  30                         continue;
  31                 for (j = 0; j < M->NbColumns - 1; ++j) {
  32                         v = isl_val_int_from_gmp(ctx, M->p[i][1 + j]);
  33                         eq = isl_mat_set_element_val(eq, i, j, v);
  34                 }
  35         }
  36
  37         return eq;
  38 }
  39
  40 static __isl_give isl_mat *extract_inequalities(isl_ctx *ctx, Matrix *M)
  41 {
  42         int i, j;
  43         int n;
  44         isl_val *v;
  45         isl_mat *ineq;
  46
  47         n = 0;
  48         for (i = 0; i < M->NbRows; ++i)
  49                 if (!value_zero_p(M->p[i][0]))
  50                         ++n;
  51
  52         ineq = isl_mat_alloc(ctx, n, M->NbColumns - 1);
  53         for (i = 0; i < M->NbRows; ++i) {
  54                 if (value_zero_p(M->p[i][0]))
  55                         continue;
  56                 for (j = 0; j < M->NbColumns - 1; ++j) {
  57                         v = isl_val_int_from_gmp(ctx, M->p[i][1 + j]);
  58                         ineq = isl_mat_set_element_val(ineq, i, j, v);
  59                 }
  60         }
  61
  62         return ineq;
  63 }
  64
  65 enum order_sign isl_polyhedron_affine_sign(Polyhedron *D, Matrix *T,
  66                                             struct barvinok_options *options)
  67 {
  68         isl_ctx *ctx = isl_ctx_alloc();
  69         isl_space *dim;
  70         isl_vec *aff;
  71         isl_basic_set *bset;
  72         isl_int denom;
  73         isl_int min, max;
  74         enum isl_lp_result lp_min, lp_max;
  75         enum order_sign sign = order_undefined;
  76
  77         isl_int_init(denom);
  78         isl_int_init(min);
  79         isl_int_init(max);
  80
  81         assert(D->Dimension == T->NbColumns - 1);
  82
  83         aff = isl_vec_alloc(ctx, T->NbColumns);
  84         assert(aff);
  85         values2isl(T->p[0], aff->el + 1, T->NbColumns - 1);
  86         values2isl(T->p[0] + T->NbColumns - 1, aff->el, 1);
  87         values2isl(T->p[1] + T->NbColumns - 1, &denom, 1);
  88
  89         dim = isl_space_set_alloc(ctx, 0, D->Dimension);
  90         bset = isl_basic_set_new_from_polylib(D, dim);
  91
  92         lp_min = isl_basic_set_solve_lp(bset, 0, aff->el, denom, &min,
  93                                         NULL, NULL);
  94         assert(lp_min != isl_lp_error);
  95
  96         if (lp_min == isl_lp_empty)
  97                 sign = order_undefined;
  98         else if (lp_min == isl_lp_ok && isl_int_is_pos(min))
  99                 sign = order_gt;
 100         else {
 101                 lp_max = isl_basic_set_solve_lp(bset, 1, aff->el, denom, &max,
 102                                                 NULL, NULL);
 103                 assert(lp_max != isl_lp_error);
 104
 105                 if (lp_max == isl_lp_ok && isl_int_is_neg(max))
 106                         sign = order_lt;
 107                 else if (lp_min == isl_lp_ok && lp_max == isl_lp_ok &&
 108                          isl_int_is_zero(min) && isl_int_is_zero(max))
 109                         sign = order_eq;
 110                 else if (lp_min == isl_lp_ok && isl_int_is_zero(min))
 111                         sign = order_ge;
 112                 else if (lp_max == isl_lp_ok && isl_int_is_zero(max))
 113                         sign = order_le;
 114                 else
 115                         sign = order_unknown;
 116         }
 117
 118         isl_basic_set_free(bset);
 119         isl_vec_free(aff);
 120         isl_int_clear(min);
 121         isl_int_clear(max);
 122         isl_int_clear(denom);
 123         isl_ctx_free(ctx);
 124
 125         return sign;
 126 }
 127
 128 static enum lp_result isl_lp_result2lp_result(enum isl_lp_result res)
 129 {
 130         switch (res) {
 131         case isl_lp_ok:
 132                 return lp_ok;
 133         case isl_lp_unbounded:
 134                 return lp_unbounded;
 135         case isl_lp_empty:
 136                 return lp_empty;
 137         default:
 138                 assert(0);
 139         }
 140 }
 141
 142 enum lp_result isl_constraints_opt(Matrix *C, Value *obj, Value denom,
 143                                     enum lp_dir dir, Value *opt)
 144 {
 145         isl_ctx *ctx = isl_ctx_alloc();
 146         isl_space *dim;
 147         isl_mat *eq, *ineq;
 148         isl_basic_set *bset;
 149         isl_int isl_denom, isl_opt;
 150         isl_vec *aff;
 151         enum isl_lp_result res;
 152         int max = dir == lp_max;
 153
 154         isl_int_init(isl_denom);
 155         isl_int_init(isl_opt);
 156
 157         eq = extract_equalities(ctx, C);
 158         ineq = extract_inequalities(ctx, C);
 159         dim = isl_space_set_alloc(ctx, 0, C->NbColumns - 2);
 160         bset = isl_basic_set_from_constraint_matrices(dim, eq, ineq,
 161                         isl_dim_set, isl_dim_div, isl_dim_param, isl_dim_cst);
 162         aff = isl_vec_alloc(ctx, C->NbColumns - 1);
 163         assert(aff);
 164         values2isl(obj, aff->el + 1, aff->size - 1);
 165         values2isl(obj + aff->size - 1, aff->el, 1);
 166         isl_int_set_gmp(isl_denom, denom);
 167
 168         res = isl_basic_set_solve_lp(bset, max, aff->el, isl_denom, &isl_opt,
 169                                         NULL, NULL);
 170         isl_int_get_gmp(isl_opt, *opt);
 171
 172         isl_vec_free(aff);
 173         isl_int_clear(isl_denom);
 174         isl_int_clear(isl_opt);
 175         isl_basic_set_free(bset);
 176         isl_ctx_free(ctx);
 177
 178         return isl_lp_result2lp_result(res);
 179 }