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