isl_sample_piplib.c

   1 #include "isl_mat.h"
   2 #include "isl_vec.h"
   3 #include "isl_seq.h"
   4 #include "isl_piplib.h"
   5 #include "isl_sample_piplib.h"
   6
   7 static void swap_inequality(struct isl_basic_set *bset, int a, int b)
   8 {
   9         isl_int *t = bset->ineq[a];
  10         bset->ineq[a] = bset->ineq[b];
  11         bset->ineq[b] = t;
  12 }
  13
  14 static struct isl_mat *independent_bounds(struct isl_ctx *ctx,
  15         struct isl_basic_set *bset)
  16 {
  17         int i, j, n;
  18         struct isl_mat *dirs = NULL;
  19         struct isl_mat *bounds = NULL;
  20
  21         if (!bset)
  22                 return NULL;
  23
  24         bounds = isl_mat_alloc(ctx, 1+bset->dim, 1+bset->dim);
  25         if (!bounds)
  26                 return NULL;
  27
  28         isl_int_set_si(bounds->row[0][0], 1);
  29         isl_seq_clr(bounds->row[0]+1, bset->dim);
  30         bounds->n_row = 1;
  31
  32         if (bset->n_ineq == 0)
  33                 return bounds;
  34
  35         dirs = isl_mat_alloc(ctx, bset->dim, bset->dim);
  36         if (!dirs) {
  37                 isl_mat_free(ctx, bounds);
  38                 return NULL;
  39         }
  40         isl_seq_cpy(dirs->row[0], bset->ineq[0]+1, dirs->n_col);
  41         isl_seq_cpy(bounds->row[1], bset->ineq[0], bounds->n_col);
  42         for (j = 1, n = 1; n < bset->dim && j < bset->n_ineq; ++j) {
  43                 int pos;
  44
  45                 isl_seq_cpy(dirs->row[n], bset->ineq[j]+1, dirs->n_col);
  46
  47                 pos = isl_seq_first_non_zero(dirs->row[n], dirs->n_col);
  48                 if (pos < 0)
  49                         continue;
  50                 for (i = 0; i < n; ++i) {
  51                         int pos_i;
  52                         pos_i = isl_seq_first_non_zero(dirs->row[i], dirs->n_col);
  53                         if (pos_i < pos)
  54                                 continue;
  55                         if (pos_i > pos)
  56                                 break;
  57                         isl_seq_elim(dirs->row[n], dirs->row[i], pos,
  58                                         dirs->n_col, NULL);
  59                         pos = isl_seq_first_non_zero(dirs->row[n], dirs->n_col);
  60                         if (pos < 0)
  61                                 break;
  62                 }
  63                 if (pos < 0)
  64                         continue;
  65                 if (i < n) {
  66                         int k;
  67                         isl_int *t = dirs->row[n];
  68                         for (k = n; k > i; --k)
  69                                 dirs->row[k] = dirs->row[k-1];
  70                         dirs->row[i] = t;
  71                 }
  72                 ++n;
  73                 isl_seq_cpy(bounds->row[n], bset->ineq[j], bounds->n_col);
  74         }
  75         isl_mat_free(ctx, dirs);
  76         bounds->n_row = 1+n;
  77         return bounds;
  78 }
  79
  80 /* Skew into positive orthant and project out lineality space */
  81 static struct isl_basic_set *isl_basic_set_skew_to_positive_orthant(
  82         struct isl_basic_set *bset, struct isl_mat **T)
  83 {
  84         struct isl_mat *U = NULL;
  85         struct isl_mat *bounds = NULL;
  86         int i, j;
  87         unsigned old_dim, new_dim;
  88         struct isl_ctx *ctx;
  89
  90         *T = NULL;
  91         if (!bset)
  92                 return NULL;
  93
  94         ctx = bset->ctx;
  95         isl_assert(ctx, bset->nparam == 0, goto error);
  96         isl_assert(ctx, bset->n_div == 0, goto error);
  97         isl_assert(ctx, bset->n_eq == 0, goto error);
  98
  99         /* Try to move (multiples of) unit rows up. */
 100         for (i = 0, j = 0; i < bset->n_ineq; ++i) {
 101                 int pos = isl_seq_first_non_zero(bset->ineq[i]+1,
 102                                                             bset->dim);
 103                 if (pos < 0)
 104                         continue;
 105                 if (isl_seq_first_non_zero(bset->ineq[i]+1+pos+1,
 106                                                 bset->dim-pos-1) >= 0)
 107                         continue;
 108                 if (i != j)
 109                         swap_inequality(bset, i, j);
 110                 ++j;
 111         }
 112         bounds = independent_bounds(ctx, bset);
 113         if (!bounds)
 114                 goto error;
 115         old_dim = bset->dim;
 116         new_dim = bounds->n_row - 1;
 117         bounds = isl_mat_left_hermite(ctx, bounds, 1, &U, NULL);
 118         if (!bounds)
 119                 goto error;
 120         U = isl_mat_drop_cols(ctx, U, 1 + new_dim, old_dim - new_dim);
 121         bset = isl_basic_set_preimage(ctx, bset, isl_mat_copy(ctx, U));
 122         if (!bset)
 123                 goto error;
 124         *T = U;
 125         isl_mat_free(ctx, bounds);
 126         return bset;
 127 error:
 128         isl_mat_free(ctx, bounds);
 129         isl_mat_free(ctx, U);
 130         isl_basic_set_free(bset);
 131         return NULL;
 132 }
 133
 134 struct isl_vec *isl_pip_basic_set_sample(struct isl_basic_set *bset)
 135 {
 136         PipOptions      *options = NULL;
 137         PipMatrix       *domain = NULL;
 138         PipQuast        *sol = NULL;
 139         struct isl_vec *vec = NULL;
 140         unsigned        dim;
 141         struct isl_mat *T;
 142         struct isl_ctx *ctx;
 143
 144         if (!bset)
 145                 goto error;
 146         ctx = bset->ctx;
 147         isl_assert(ctx, bset->nparam == 0, goto error);
 148         isl_assert(ctx, bset->n_div == 0, goto error);
 149         bset = isl_basic_set_skew_to_positive_orthant(bset, &T);
 150         if (!bset)
 151                 goto error;
 152         dim = bset->dim;
 153         domain = isl_basic_map_to_pip((struct isl_basic_map *)bset, 0, 0, 0);
 154         if (!domain)
 155                 goto error;
 156
 157         options = pip_options_init();
 158         if (!options)
 159                 goto error;
 160         sol = pip_solve(domain, NULL, -1, options);
 161         if (!sol)
 162                 goto error;
 163         if (!sol->list) {
 164                 vec = isl_vec_alloc(ctx, 0);
 165                 isl_mat_free(ctx, T);
 166         } else {
 167                 PipList *l;
 168                 int i;
 169                 vec = isl_vec_alloc(ctx, 1 + dim);
 170                 if (!vec)
 171                         goto error;
 172                 isl_int_set_si(vec->block.data[0], 1);
 173                 for (i = 0, l = sol->list; l && i < dim; ++i, l = l->next) {
 174                         isl_seq_cpy_from_pip(&vec->block.data[1+i],
 175                                         &l->vector->the_vector[0], 1);
 176                         isl_assert(ctx, !entier_zero_p(l->vector->the_deno[0]),
 177                                         goto error);
 178                 }
 179                 isl_assert(ctx, i == dim, goto error);
 180                 vec = isl_mat_vec_product(ctx, T, vec);
 181         }
 182
 183         pip_quast_free(sol);
 184         pip_options_free(options);
 185         pip_matrix_free(domain);
 186
 187         isl_basic_set_free(bset);
 188         return vec;
 189 error:
 190         isl_vec_free(ctx, vec);
 191         isl_basic_set_free(bset);
 192         if (sol)
 193                 pip_quast_free(sol);
 194         if (domain)
 195                 pip_matrix_free(domain);
 196         return NULL;
 197 }