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 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         opt = opt_at(isl_basic_set_copy(sp->bset), isl_vec_copy(sample), sp->max);
 191         assert(opt);
 192
 193         if (opt->size == 0) {
 194                 isl_point *sample_pnt;
 195                 sample_pnt = isl_point_alloc(isl_set_get_dim(sp->empty), sample);
 196                 assert(isl_set_contains_point(sp->empty, sample_pnt));
 197                 isl_point_free(sample_pnt);
 198                 isl_vec_free(opt);
 199         } else {
 200                 isl_set *sol;
 201                 isl_set *opt_set;
 202                 opt_set = isl_set_from_basic_set(isl_basic_set_from_vec(opt));
 203                 sol = set_plug_in_parameters(isl_set_copy(sp->sol), sample);
 204                 assert(isl_set_is_equal(opt_set, sol));
 205                 isl_set_free(sol);
 206                 isl_set_free(opt_set);
 207         }
 208
 209         if (!(sp->n++ % sp->stride)) {
 210                 printf("o");
 211                 fflush(stdout);
 212         }
 213
 214         return 0;
 215 }
 216
 217 struct isl_scan_count {
 218         struct isl_scan_callback callback;
 219         int n;
 220 };
 221
 222 static int count_one(struct isl_scan_callback *callback,
 223         __isl_take isl_vec *sample)
 224 {
 225         struct isl_scan_count *sc = (struct isl_scan_count *)callback;
 226         isl_vec_free(sample);
 227
 228         sc->n++;
 229
 230         return 0;
 231 }
 232
 233 static void check_solution(isl_basic_set *bset, isl_basic_set *context,
 234         isl_set *sol, isl_set *empty, int max)
 235 {
 236         struct isl_scan_count sc;
 237         struct isl_scan_pip sp;
 238         int i;
 239         int r;
 240
 241         context = set_bounds(context);
 242         context = isl_basic_set_underlying_set(context);
 243
 244         sc.callback.add = count_one;
 245         sc.n = 0;
 246
 247         r = isl_basic_set_scan(isl_basic_set_copy(context), &sc.callback);
 248         assert (r == 0);
 249
 250         sp.callback.add = scan_one;
 251         sp.bset = bset;
 252         sp.sol = sol;
 253         sp.empty = empty;
 254         sp.n = 0;
 255         sp.stride = sc.n > 70 ? 1 + (sc.n + 1)/70 : 1;
 256         sp.max = max;
 257
 258         for (i = 0; i < sc.n; i += sp.stride)
 259                 printf(".");
 260         printf("\r");
 261         fflush(stdout);
 262
 263         r = isl_basic_set_scan(context, &sp.callback);
 264         assert(r == 0);
 265
 266         printf("\n");
 267
 268         isl_basic_set_free(bset);
 269 }
 270
 271 int main(int argc, char **argv)
 272 {
 273         struct isl_ctx *ctx;
 274         struct isl_basic_set *context, *bset, *copy, *context_copy;
 275         struct isl_set *set;
 276         struct isl_set *empty;
 277         int neg_one;
 278         char s[1024];
 279         int urs_parms = 0;
 280         int urs_unknowns = 0;
 281         int max = 0;
 282         int rational = 0;
 283         int n;
 284         struct options *options;
 285
 286         options = options_new_with_defaults();
 287         assert(options);
 288         argc = options_parse(options, argc, argv, ISL_ARG_ALL);
 289
 290         ctx = isl_ctx_alloc_with_options(options_arg, options);
 291
 292         context = isl_basic_set_read_from_file(ctx, stdin, 0);
 293         assert(context);
 294         n = fscanf(stdin, "%d", &neg_one);
 295         assert(n == 1);
 296         assert(neg_one == -1);
 297         bset = isl_basic_set_read_from_file(ctx, stdin,
 298                 isl_basic_set_dim(context, isl_dim_set));
 299
 300         while (fgets(s, sizeof(s), stdin)) {
 301                 if (strncasecmp(s, "Maximize", 8) == 0)
 302                         max = 1;
 303                 if (strncasecmp(s, "Rational", 8) == 0) {
 304                         rational = 1;
 305                         bset = isl_basic_set_set_rational(bset);
 306                 }
 307                 if (strncasecmp(s, "Urs_parms", 9) == 0)
 308                         urs_parms = 1;
 309                 if (strncasecmp(s, "Urs_unknowns", 12) == 0)
 310                         urs_unknowns = 1;
 311         }
 312         if (!urs_parms)
 313                 context = isl_basic_set_intersect(context,
 314                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(context)));
 315         context = to_parameter_domain(context);
 316         if (!urs_unknowns)
 317                 bset = isl_basic_set_intersect(bset,
 318                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(bset)));
 319
 320         if (options->verify) {
 321                 copy = isl_basic_set_copy(bset);
 322                 context_copy = isl_basic_set_copy(context);
 323         }
 324
 325         if (max)
 326                 set = isl_basic_set_partial_lexmax(bset, context, &empty);
 327         else
 328                 set = isl_basic_set_partial_lexmin(bset, context, &empty);
 329
 330         if (options->verify) {
 331                 assert(!rational);
 332                 check_solution(copy, context_copy, set, empty, max);
 333         } else {
 334                 isl_set_print(set, stdout, 0, ISL_FORMAT_ISL);
 335                 fprintf(stdout, "\n");
 336                 fprintf(stdout, "no solution: ");
 337                 isl_set_print(empty, stdout, 0, ISL_FORMAT_ISL);
 338                 fprintf(stdout, "\n");
 339         }
 340
 341         isl_set_free(set);
 342         isl_set_free(empty);
 343         isl_ctx_free(ctx);
 344
 345         return 0;
 346 }