pip.c

   1 /*
   2  * Copyright 2008-2009 Katholieke Universiteit Leuven
   3  *
   4  * Use of this software is governed by the GNU LGPLv2.1 license
   5  *
   6  * Written by Sven Verdoolaege, K.U.Leuven, Departement
   7  * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
   8  */
   9
  10 #include <assert.h>
  11 #include <string.h>
  12 #include <isl_map_private.h>
  13 #include <isl/set.h>
  14 #include "isl_tab.h"
  15 #include "isl_sample.h"
  16 #include "isl_scan.h"
  17 #include <isl/seq.h>
  18 #include <isl/ilp.h>
  19 #include <isl_point_private.h>
  20
  21 /* The input of this program is the same as that of the "example" program
  22  * from the PipLib distribution, except that the "big parameter column"
  23  * should always be -1.
  24  *
  25  * Context constraints in PolyLib format
  26  * -1
  27  * Problem constraints in PolyLib format
  28  * Optional list of options
  29  *
  30  * The options are
  31  *      Maximize        compute maximum instead of minimum
  32  *      Rational        compute rational optimum instead of integer optimum
  33  *      Urs_parms       don't assume parameters are non-negative
  34  *      Urs_unknowns    don't assume unknowns are non-negative
  35  */
  36
  37 struct options {
  38         struct isl_options      *isl;
  39         unsigned                 verify;
  40 };
  41
  42 struct isl_arg options_arg[] = {
  43 ISL_ARG_CHILD(struct options, isl, "isl", isl_options_arg, "isl options")
  44 ISL_ARG_BOOL(struct options, verify, 'T', "verify", 0, NULL)
  45 ISL_ARG_END
  46 };
  47
  48 ISL_ARG_DEF(options, struct options, options_arg)
  49
  50 static __isl_give isl_basic_set *set_bounds(__isl_take isl_basic_set *bset)
  51 {
  52         unsigned nparam;
  53         int i, r;
  54         isl_point *pt, *pt2;
  55         isl_basic_set *box;
  56
  57         nparam = isl_basic_set_dim(bset, isl_dim_param);
  58         r = nparam >= 8 ? 4 : nparam >= 5 ? 6 : 30;
  59
  60         pt = isl_basic_set_sample_point(isl_basic_set_copy(bset));
  61         pt2 = isl_point_copy(pt);
  62
  63         for (i = 0; i < nparam; ++i) {
  64                 pt = isl_point_add_ui(pt, isl_dim_param, i, r);
  65                 pt2 = isl_point_sub_ui(pt2, isl_dim_param, i, r);
  66         }
  67
  68         box = isl_basic_set_box_from_points(pt, pt2);
  69
  70         return isl_basic_set_intersect(bset, box);
  71 }
  72
  73 static struct isl_basic_set *to_parameter_domain(struct isl_basic_set *context)
  74 {
  75         return isl_basic_set_move_dims(context, isl_dim_param, 0, isl_dim_set, 0,
  76                                        isl_basic_set_dim(context, isl_dim_set));
  77 }
  78
  79 isl_basic_set *plug_in_parameters(isl_basic_set *bset, struct isl_vec *params)
  80 {
  81         int i;
  82
  83         for (i = 0; i < params->size - 1; ++i)
  84                 bset = isl_basic_set_fix(bset,
  85                                          isl_dim_param, i, params->el[1 + i]);
  86
  87         bset = isl_basic_set_remove_dims(bset,
  88                                          isl_dim_param, 0, params->size - 1);
  89
  90         isl_vec_free(params);
  91
  92         return bset;
  93 }
  94
  95 isl_set *set_plug_in_parameters(isl_set *set, struct isl_vec *params)
  96 {
  97         int i;
  98
  99         for (i = 0; i < params->size - 1; ++i)
 100                 set = isl_set_fix(set, isl_dim_param, i, params->el[1 + i]);
 101
 102         set = isl_set_remove_dims(set, isl_dim_param, 0, params->size - 1);
 103
 104         isl_vec_free(params);
 105
 106         return set;
 107 }
 108
 109 /* Compute the lexicographically minimal (or maximal if max is set)
 110  * element of bset for the given values of the parameters, by
 111  * successively solving an ilp problem in each direction.
 112  */
 113 struct isl_vec *opt_at(struct isl_basic_set *bset,
 114         struct isl_vec *params, int max)
 115 {
 116         unsigned dim;
 117         struct isl_vec *opt;
 118         struct isl_vec *obj;
 119         int i;
 120
 121         dim = isl_basic_set_dim(bset, isl_dim_set);
 122
 123         bset = plug_in_parameters(bset, params);
 124
 125         if (isl_basic_set_fast_is_empty(bset)) {
 126                 opt = isl_vec_alloc(bset->ctx, 0);
 127                 isl_basic_set_free(bset);
 128                 return opt;
 129         }
 130
 131         opt = isl_vec_alloc(bset->ctx, 1 + dim);
 132         assert(opt);
 133
 134         obj = isl_vec_alloc(bset->ctx, 1 + dim);
 135         assert(obj);
 136
 137         isl_int_set_si(opt->el[0], 1);
 138         isl_int_set_si(obj->el[0], 0);
 139
 140         for (i = 0; i < dim; ++i) {
 141                 enum isl_lp_result res;
 142
 143                 isl_seq_clr(obj->el + 1, dim);
 144                 isl_int_set_si(obj->el[1 + i], 1);
 145                 res = isl_basic_set_solve_ilp(bset, max, obj->el,
 146                                                 &opt->el[1 + i], NULL);
 147                 if (res == isl_lp_empty)
 148                         goto empty;
 149                 assert(res == isl_lp_ok);
 150                 bset = isl_basic_set_fix(bset, isl_dim_set, i, opt->el[1 + i]);
 151         }
 152
 153         isl_basic_set_free(bset);
 154         isl_vec_free(obj);
 155
 156         return opt;
 157 empty:
 158         isl_vec_free(opt);
 159         opt = isl_vec_alloc(bset->ctx, 0);
 160         isl_basic_set_free(bset);
 161         isl_vec_free(obj);
 162
 163         return opt;
 164 }
 165
 166 struct isl_scan_pip {
 167         struct isl_scan_callback callback;
 168         isl_basic_set *bset;
 169         isl_set *sol;
 170         isl_set *empty;
 171         int stride;
 172         int n;
 173         int max;
 174 };
 175
 176 /* Check if the "manually" computed optimum of bset at the "sample"
 177  * values of the parameters agrees with the solution of pilp problem
 178  * represented by the pair (sol, empty).
 179  * In particular, if there is no solution for this value of the parameters,
 180  * then it should be an element of the parameter domain "empty".
 181  * Otherwise, the optimal solution, should be equal to the result of
 182  * plugging in the value of the parameters in "sol".
 183  */
 184 static int scan_one(struct isl_scan_callback *callback,
 185         __isl_take isl_vec *sample)
 186 {
 187         struct isl_scan_pip *sp = (struct isl_scan_pip *)callback;
 188         struct isl_vec *opt;
 189
 190         sp->n--;
 191
 192         opt = opt_at(isl_basic_set_copy(sp->bset), isl_vec_copy(sample), sp->max);
 193         assert(opt);
 194
 195         if (opt->size == 0) {
 196                 isl_point *sample_pnt;
 197                 sample_pnt = isl_point_alloc(isl_set_get_dim(sp->empty), sample);
 198                 assert(isl_set_contains_point(sp->empty, sample_pnt));
 199                 isl_point_free(sample_pnt);
 200                 isl_vec_free(opt);
 201         } else {
 202                 isl_set *sol;
 203                 isl_set *opt_set;
 204                 opt_set = isl_set_from_basic_set(isl_basic_set_from_vec(opt));
 205                 sol = set_plug_in_parameters(isl_set_copy(sp->sol), sample);
 206                 assert(isl_set_is_equal(opt_set, sol));
 207                 isl_set_free(sol);
 208                 isl_set_free(opt_set);
 209         }
 210
 211         if (!(sp->n % sp->stride)) {
 212                 printf("o");
 213                 fflush(stdout);
 214         }
 215
 216         return sp->n >= 1 ? 0 : -1;
 217 }
 218
 219 static void check_solution(isl_basic_set *bset, isl_basic_set *context,
 220         isl_set *sol, isl_set *empty, int max)
 221 {
 222         struct isl_scan_pip sp;
 223         isl_int count, count_max;
 224         int i, n;
 225         int r;
 226
 227         context = set_bounds(context);
 228         context = isl_basic_set_underlying_set(context);
 229
 230         isl_int_init(count);
 231         isl_int_init(count_max);
 232
 233         isl_int_set_si(count_max, 2000);
 234         r = isl_basic_set_count_upto(context, count_max, &count);
 235         assert(r >= 0);
 236         n = isl_int_get_si(count);
 237
 238         isl_int_clear(count_max);
 239         isl_int_clear(count);
 240
 241         sp.callback.add = scan_one;
 242         sp.bset = bset;
 243         sp.sol = sol;
 244         sp.empty = empty;
 245         sp.n = n;
 246         sp.stride = n > 70 ? 1 + (n + 1)/70 : 1;
 247         sp.max = max;
 248
 249         for (i = 0; i < n; i += sp.stride)
 250                 printf(".");
 251         printf("\r");
 252         fflush(stdout);
 253
 254         isl_basic_set_scan(context, &sp.callback);
 255
 256         printf("\n");
 257
 258         isl_basic_set_free(bset);
 259 }
 260
 261 int main(int argc, char **argv)
 262 {
 263         struct isl_ctx *ctx;
 264         struct isl_basic_set *context, *bset, *copy, *context_copy;
 265         struct isl_set *set;
 266         struct isl_set *empty;
 267         int neg_one;
 268         char s[1024];
 269         int urs_parms = 0;
 270         int urs_unknowns = 0;
 271         int max = 0;
 272         int rational = 0;
 273         int n;
 274         struct options *options;
 275
 276         options = options_new_with_defaults();
 277         assert(options);
 278         argc = options_parse(options, argc, argv, ISL_ARG_ALL);
 279
 280         ctx = isl_ctx_alloc_with_options(options_arg, options);
 281
 282         context = isl_basic_set_read_from_file(ctx, stdin, 0);
 283         assert(context);
 284         n = fscanf(stdin, "%d", &neg_one);
 285         assert(n == 1);
 286         assert(neg_one == -1);
 287         bset = isl_basic_set_read_from_file(ctx, stdin,
 288                 isl_basic_set_dim(context, isl_dim_set));
 289
 290         while (fgets(s, sizeof(s), stdin)) {
 291                 if (strncasecmp(s, "Maximize", 8) == 0)
 292                         max = 1;
 293                 if (strncasecmp(s, "Rational", 8) == 0) {
 294                         rational = 1;
 295                         bset = isl_basic_set_set_rational(bset);
 296                 }
 297                 if (strncasecmp(s, "Urs_parms", 9) == 0)
 298                         urs_parms = 1;
 299                 if (strncasecmp(s, "Urs_unknowns", 12) == 0)
 300                         urs_unknowns = 1;
 301         }
 302         if (!urs_parms)
 303                 context = isl_basic_set_intersect(context,
 304                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(context)));
 305         context = to_parameter_domain(context);
 306         if (!urs_unknowns)
 307                 bset = isl_basic_set_intersect(bset,
 308                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(bset)));
 309
 310         if (options->verify) {
 311                 copy = isl_basic_set_copy(bset);
 312                 context_copy = isl_basic_set_copy(context);
 313         }
 314
 315         if (max)
 316                 set = isl_basic_set_partial_lexmax(bset, context, &empty);
 317         else
 318                 set = isl_basic_set_partial_lexmin(bset, context, &empty);
 319
 320         if (options->verify) {
 321                 assert(!rational);
 322                 check_solution(copy, context_copy, set, empty, max);
 323         } else {
 324                 isl_set_print(set, stdout, 0, ISL_FORMAT_ISL);
 325                 fprintf(stdout, "\n");
 326                 fprintf(stdout, "no solution: ");
 327                 isl_set_print(empty, stdout, 0, ISL_FORMAT_ISL);
 328                 fprintf(stdout, "\n");
 329         }
 330
 331         isl_set_free(set);
 332         isl_set_free(empty);
 333         isl_ctx_free(ctx);
 334
 335         return 0;
 336 }