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_set.h"
  13 #include "isl_tab.h"
  14 #include "isl_map_private.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 pip_options {
  38         struct isl_options      *isl;
  39         unsigned                 verify;
  40 };
  41
  42 struct isl_arg pip_options_arg[] = {
  43 ISL_ARG_CHILD(struct pip_options, isl, "isl", isl_options_arg)
  44 ISL_ARG_BOOL(struct pip_options, verify, 'T', "verify", 0)
  45 };
  46
  47 ISL_ARG_DEF(pip_options, struct pip_options, pip_options_arg)
  48
  49 static struct isl_basic_set *to_parameter_domain(struct isl_basic_set *context)
  50 {
  51         struct isl_dim *param_dim;
  52         struct isl_basic_set *model;
  53
  54         param_dim = isl_dim_set_alloc(context->ctx,
  55                                         isl_basic_set_n_dim(context), 0);
  56         model = isl_basic_set_empty(param_dim);
  57         context = isl_basic_set_from_underlying_set(context, model);
  58
  59         return context;
  60 }
  61
  62 static isl_basic_set *construct_cube(isl_basic_set *context)
  63 {
  64         int i;
  65         unsigned dim;
  66         int range;
  67         isl_int m, M;
  68         struct isl_basic_set *cube;
  69         struct isl_basic_set *interval;
  70         struct isl_basic_set_list *list;
  71
  72         dim = isl_basic_set_total_dim(context);
  73         if (dim == 0) {
  74                 struct isl_dim *dims;
  75                 dims = isl_dim_set_alloc(context->ctx, 0, 0);
  76                 return isl_basic_set_universe(dims);
  77         }
  78
  79         if (dim >= 8)
  80                 range = 4;
  81         else if (dim >= 5)
  82                 range = 6;
  83         else
  84                 range = 30;
  85
  86         isl_int_init(m);
  87         isl_int_init(M);
  88
  89         isl_int_set_si(m, -range);
  90         isl_int_set_si(M, range);
  91
  92         interval = isl_basic_set_interval(context->ctx, m, M);
  93         list = isl_basic_set_list_alloc(context->ctx, dim);
  94         for (i = 0; i < dim; ++i)
  95                 list = isl_basic_set_list_add(list, isl_basic_set_copy(interval));
  96         isl_basic_set_free(interval);
  97         cube = isl_basic_set_product(list);
  98
  99         isl_int_clear(m);
 100         isl_int_clear(M);
 101
 102         return cube;
 103 }
 104
 105 isl_basic_set *plug_in_parameters(isl_basic_set *bset, struct isl_vec *params)
 106 {
 107         int i;
 108
 109         for (i = 0; i < params->size - 1; ++i)
 110                 bset = isl_basic_set_fix(bset,
 111                                          isl_dim_param, i, params->el[1 + i]);
 112
 113         bset = isl_basic_set_remove(bset, isl_dim_param, 0, params->size - 1);
 114
 115         isl_vec_free(params);
 116
 117         return bset;
 118 }
 119
 120 isl_set *set_plug_in_parameters(isl_set *set, struct isl_vec *params)
 121 {
 122         int i;
 123
 124         for (i = 0; i < params->size - 1; ++i)
 125                 set = isl_set_fix(set, isl_dim_param, i, params->el[1 + i]);
 126
 127         set = isl_set_remove(set, isl_dim_param, 0, params->size - 1);
 128
 129         isl_vec_free(params);
 130
 131         return set;
 132 }
 133
 134 /* Compute the lexicographically minimal (or maximal if max is set)
 135  * element of bset for the given values of the parameters, by
 136  * successively solving an ilp problem in each direction.
 137  */
 138 struct isl_vec *opt_at(struct isl_basic_set *bset,
 139         struct isl_vec *params, int max)
 140 {
 141         unsigned dim;
 142         struct isl_vec *opt;
 143         struct isl_vec *obj;
 144         int i;
 145
 146         dim = isl_basic_set_dim(bset, isl_dim_set);
 147
 148         bset = plug_in_parameters(bset, params);
 149
 150         if (isl_basic_set_fast_is_empty(bset)) {
 151                 opt = isl_vec_alloc(bset->ctx, 0);
 152                 isl_basic_set_free(bset);
 153                 return opt;
 154         }
 155
 156         opt = isl_vec_alloc(bset->ctx, 1 + dim);
 157         assert(opt);
 158
 159         obj = isl_vec_alloc(bset->ctx, 1 + dim);
 160         assert(obj);
 161
 162         isl_int_set_si(opt->el[0], 1);
 163         isl_int_set_si(obj->el[0], 0);
 164
 165         for (i = 0; i < dim; ++i) {
 166                 enum isl_lp_result res;
 167
 168                 isl_seq_clr(obj->el + 1, dim);
 169                 isl_int_set_si(obj->el[1 + i], 1);
 170                 res = isl_basic_set_solve_ilp(bset, max, obj->el,
 171                                                 &opt->el[1 + i], NULL);
 172                 if (res == isl_lp_empty)
 173                         goto empty;
 174                 assert(res == isl_lp_ok);
 175                 bset = isl_basic_set_fix(bset, isl_dim_set, i, opt->el[1 + i]);
 176         }
 177
 178         isl_basic_set_free(bset);
 179         isl_vec_free(obj);
 180
 181         return opt;
 182 empty:
 183         isl_vec_free(opt);
 184         opt = isl_vec_alloc(bset->ctx, 0);
 185         isl_basic_set_free(bset);
 186         isl_vec_free(obj);
 187
 188         return opt;
 189 }
 190
 191 struct isl_scan_pip {
 192         struct isl_scan_callback callback;
 193         isl_basic_set *bset;
 194         isl_set *sol;
 195         isl_set *empty;
 196         int stride;
 197         int n;
 198         int max;
 199 };
 200
 201 /* Check if the "manually" computed optimum of bset at the "sample"
 202  * values of the parameters agrees with the solution of pilp problem
 203  * represented by the pair (sol, empty).
 204  * In particular, if there is no solution for this value of the parameters,
 205  * then it should be an element of the parameter domain "empty".
 206  * Otherwise, the optimal solution, should be equal to the result of
 207  * plugging in the value of the parameters in "sol".
 208  */
 209 static int scan_one(struct isl_scan_callback *callback,
 210         __isl_take isl_vec *sample)
 211 {
 212         struct isl_scan_pip *sp = (struct isl_scan_pip *)callback;
 213         struct isl_vec *opt;
 214
 215         opt = opt_at(isl_basic_set_copy(sp->bset), isl_vec_copy(sample), sp->max);
 216         assert(opt);
 217
 218         if (opt->size == 0) {
 219                 isl_point *sample_pnt;
 220                 sample_pnt = isl_point_alloc(isl_set_get_dim(sp->empty), sample);
 221                 assert(isl_set_contains_point(sp->empty, sample_pnt));
 222                 isl_point_free(sample_pnt);
 223                 isl_vec_free(opt);
 224         } else {
 225                 isl_set *sol;
 226                 isl_set *opt_set;
 227                 opt_set = isl_set_from_basic_set(isl_basic_set_from_vec(opt));
 228                 sol = set_plug_in_parameters(isl_set_copy(sp->sol), sample);
 229                 assert(isl_set_is_equal(opt_set, sol));
 230                 isl_set_free(sol);
 231                 isl_set_free(opt_set);
 232         }
 233
 234         if (!(sp->n++ % sp->stride)) {
 235                 printf("o");
 236                 fflush(stdout);
 237         }
 238
 239         return 0;
 240 }
 241
 242 struct isl_scan_count {
 243         struct isl_scan_callback callback;
 244         int n;
 245 };
 246
 247 static int count_one(struct isl_scan_callback *callback,
 248         __isl_take isl_vec *sample)
 249 {
 250         struct isl_scan_count *sc = (struct isl_scan_count *)callback;
 251         isl_vec_free(sample);
 252
 253         sc->n++;
 254
 255         return 0;
 256 }
 257
 258 static void check_solution(isl_basic_set *bset, isl_basic_set *context,
 259         isl_set *sol, isl_set *empty, int max)
 260 {
 261         isl_basic_set *cube;
 262         struct isl_scan_count sc;
 263         struct isl_scan_pip sp;
 264         int i;
 265         int r;
 266
 267         context = isl_basic_set_underlying_set(context);
 268
 269         cube = construct_cube(context);
 270         context = isl_basic_set_intersect(context, cube);
 271
 272         sc.callback.add = count_one;
 273         sc.n = 0;
 274
 275         r = isl_basic_set_scan(isl_basic_set_copy(context), &sc.callback);
 276         assert (r == 0);
 277
 278         sp.callback.add = scan_one;
 279         sp.bset = bset;
 280         sp.sol = sol;
 281         sp.empty = empty;
 282         sp.n = 0;
 283         sp.stride = sc.n > 70 ? 1 + (sc.n + 1)/70 : 1;
 284         sp.max = max;
 285
 286         for (i = 0; i < sc.n; i += sp.stride)
 287                 printf(".");
 288         printf("\r");
 289         fflush(stdout);
 290
 291         r = isl_basic_set_scan(context, &sp.callback);
 292         assert(r == 0);
 293
 294         printf("\n");
 295
 296         isl_basic_set_free(bset);
 297 }
 298
 299 int main(int argc, char **argv)
 300 {
 301         struct isl_ctx *ctx;
 302         struct isl_basic_set *context, *bset, *copy, *context_copy;
 303         struct isl_set *set;
 304         struct isl_set *empty;
 305         int neg_one;
 306         char s[1024];
 307         int urs_parms = 0;
 308         int urs_unknowns = 0;
 309         int max = 0;
 310         int rational = 0;
 311         int n;
 312         struct pip_options *options;
 313
 314         options = pip_options_new_with_defaults();
 315         assert(options);
 316         argc = pip_options_parse(options, argc, argv);
 317
 318         ctx = isl_ctx_alloc_with_options(options->isl);
 319         options->isl = NULL;
 320
 321         context = isl_basic_set_read_from_file(ctx, stdin, 0);
 322         assert(context);
 323         n = fscanf(stdin, "%d", &neg_one);
 324         assert(n == 1);
 325         assert(neg_one == -1);
 326         bset = isl_basic_set_read_from_file(ctx, stdin,
 327                 isl_basic_set_dim(context, isl_dim_set));
 328
 329         while (fgets(s, sizeof(s), stdin)) {
 330                 if (strncasecmp(s, "Maximize", 8) == 0)
 331                         max = 1;
 332                 if (strncasecmp(s, "Rational", 8) == 0) {
 333                         rational = 1;
 334                         bset = isl_basic_set_set_rational(bset);
 335                 }
 336                 if (strncasecmp(s, "Urs_parms", 9) == 0)
 337                         urs_parms = 1;
 338                 if (strncasecmp(s, "Urs_unknowns", 12) == 0)
 339                         urs_unknowns = 1;
 340         }
 341         if (!urs_parms)
 342                 context = isl_basic_set_intersect(context,
 343                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(context)));
 344         context = to_parameter_domain(context);
 345         if (!urs_unknowns)
 346                 bset = isl_basic_set_intersect(bset,
 347                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(bset)));
 348
 349         if (options->verify) {
 350                 copy = isl_basic_set_copy(bset);
 351                 context_copy = isl_basic_set_copy(context);
 352         }
 353
 354         if (max)
 355                 set = isl_basic_set_partial_lexmax(bset, context, &empty);
 356         else
 357                 set = isl_basic_set_partial_lexmin(bset, context, &empty);
 358
 359         if (options->verify) {
 360                 assert(!rational);
 361                 check_solution(copy, context_copy, set, empty, max);
 362         } else {
 363                 isl_set_print(set, stdout, 0, ISL_FORMAT_ISL);
 364                 fprintf(stdout, "\n");
 365                 fprintf(stdout, "no solution: ");
 366                 isl_set_print(empty, stdout, 0, ISL_FORMAT_ISL);
 367                 fprintf(stdout, "\n");
 368         }
 369
 370         isl_set_free(set);
 371         isl_set_free(empty);
 372         isl_ctx_free(ctx);
 373         free(options);
 374
 375         return 0;
 376 }