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 <strings.h>
  13 #include <isl_map_private.h>
  14 #include <isl/set.h>
  15 #include "isl_tab.h"
  16 #include "isl_sample.h"
  17 #include "isl_scan.h"
  18 #include <isl/seq.h>
  19 #include <isl/ilp.h>
  20 #include <isl_point_private.h>
  21
  22 /* The input of this program is the same as that of the "example" program
  23  * from the PipLib distribution, except that the "big parameter column"
  24  * should always be -1.
  25  *
  26  * Context constraints in PolyLib format
  27  * -1
  28  * Problem constraints in PolyLib format
  29  * Optional list of options
  30  *
  31  * The options are
  32  *      Maximize        compute maximum instead of minimum
  33  *      Rational        compute rational optimum instead of integer optimum
  34  *      Urs_parms       don't assume parameters are non-negative
  35  *      Urs_unknowns    don't assume unknowns are non-negative
  36  */
  37
  38 struct options {
  39         struct isl_options      *isl;
  40         unsigned                 verify;
  41 };
  42
  43 struct isl_arg options_arg[] = {
  44 ISL_ARG_CHILD(struct options, isl, "isl", isl_options_arg, "isl options")
  45 ISL_ARG_BOOL(struct options, verify, 'T', "verify", 0, NULL)
  46 ISL_ARG_END
  47 };
  48
  49 ISL_ARG_DEF(options, struct options, options_arg)
  50
  51 static __isl_give isl_basic_set *set_bounds(__isl_take isl_basic_set *bset)
  52 {
  53         unsigned nparam;
  54         int i, r;
  55         isl_point *pt, *pt2;
  56         isl_basic_set *box;
  57
  58         nparam = isl_basic_set_dim(bset, isl_dim_param);
  59         r = nparam >= 8 ? 4 : nparam >= 5 ? 6 : 30;
  60
  61         pt = isl_basic_set_sample_point(isl_basic_set_copy(bset));
  62         pt2 = isl_point_copy(pt);
  63
  64         for (i = 0; i < nparam; ++i) {
  65                 pt = isl_point_add_ui(pt, isl_dim_param, i, r);
  66                 pt2 = isl_point_sub_ui(pt2, isl_dim_param, i, r);
  67         }
  68
  69         box = isl_basic_set_box_from_points(pt, pt2);
  70
  71         return isl_basic_set_intersect(bset, box);
  72 }
  73
  74 static struct isl_basic_set *to_parameter_domain(struct isl_basic_set *context)
  75 {
  76         return isl_basic_set_move_dims(context, isl_dim_param, 0, isl_dim_set, 0,
  77                                        isl_basic_set_dim(context, isl_dim_set));
  78 }
  79
  80 isl_basic_set *plug_in_parameters(isl_basic_set *bset, struct isl_vec *params)
  81 {
  82         int i;
  83
  84         for (i = 0; i < params->size - 1; ++i)
  85                 bset = isl_basic_set_fix(bset,
  86                                          isl_dim_param, i, params->el[1 + i]);
  87
  88         bset = isl_basic_set_remove_dims(bset,
  89                                          isl_dim_param, 0, params->size - 1);
  90
  91         isl_vec_free(params);
  92
  93         return bset;
  94 }
  95
  96 isl_set *set_plug_in_parameters(isl_set *set, struct isl_vec *params)
  97 {
  98         int i;
  99
 100         for (i = 0; i < params->size - 1; ++i)
 101                 set = isl_set_fix(set, isl_dim_param, i, params->el[1 + i]);
 102
 103         set = isl_set_remove_dims(set, isl_dim_param, 0, params->size - 1);
 104
 105         isl_vec_free(params);
 106
 107         return set;
 108 }
 109
 110 /* Compute the lexicographically minimal (or maximal if max is set)
 111  * element of bset for the given values of the parameters, by
 112  * successively solving an ilp problem in each direction.
 113  */
 114 struct isl_vec *opt_at(struct isl_basic_set *bset,
 115         struct isl_vec *params, int max)
 116 {
 117         unsigned dim;
 118         struct isl_vec *opt;
 119         struct isl_vec *obj;
 120         int i;
 121
 122         dim = isl_basic_set_dim(bset, isl_dim_set);
 123
 124         bset = plug_in_parameters(bset, params);
 125
 126         if (isl_basic_set_plain_is_empty(bset)) {
 127                 opt = isl_vec_alloc(bset->ctx, 0);
 128                 isl_basic_set_free(bset);
 129                 return opt;
 130         }
 131
 132         opt = isl_vec_alloc(bset->ctx, 1 + dim);
 133         assert(opt);
 134
 135         obj = isl_vec_alloc(bset->ctx, 1 + dim);
 136         assert(obj);
 137
 138         isl_int_set_si(opt->el[0], 1);
 139         isl_int_set_si(obj->el[0], 0);
 140
 141         for (i = 0; i < dim; ++i) {
 142                 enum isl_lp_result res;
 143
 144                 isl_seq_clr(obj->el + 1, dim);
 145                 isl_int_set_si(obj->el[1 + i], 1);
 146                 res = isl_basic_set_solve_ilp(bset, max, obj->el,
 147                                                 &opt->el[1 + i], NULL);
 148                 if (res == isl_lp_empty)
 149                         goto empty;
 150                 assert(res == isl_lp_ok);
 151                 bset = isl_basic_set_fix(bset, isl_dim_set, i, opt->el[1 + i]);
 152         }
 153
 154         isl_basic_set_free(bset);
 155         isl_vec_free(obj);
 156
 157         return opt;
 158 empty:
 159         isl_vec_free(opt);
 160         opt = isl_vec_alloc(bset->ctx, 0);
 161         isl_basic_set_free(bset);
 162         isl_vec_free(obj);
 163
 164         return opt;
 165 }
 166
 167 struct isl_scan_pip {
 168         struct isl_scan_callback callback;
 169         isl_basic_set *bset;
 170         isl_set *sol;
 171         isl_set *empty;
 172         int stride;
 173         int n;
 174         int max;
 175 };
 176
 177 /* Check if the "manually" computed optimum of bset at the "sample"
 178  * values of the parameters agrees with the solution of pilp problem
 179  * represented by the pair (sol, empty).
 180  * In particular, if there is no solution for this value of the parameters,
 181  * then it should be an element of the parameter domain "empty".
 182  * Otherwise, the optimal solution, should be equal to the result of
 183  * plugging in the value of the parameters in "sol".
 184  */
 185 static int scan_one(struct isl_scan_callback *callback,
 186         __isl_take isl_vec *sample)
 187 {
 188         struct isl_scan_pip *sp = (struct isl_scan_pip *)callback;
 189         struct isl_vec *opt;
 190
 191         sp->n--;
 192
 193         opt = opt_at(isl_basic_set_copy(sp->bset), isl_vec_copy(sample), sp->max);
 194         assert(opt);
 195
 196         if (opt->size == 0) {
 197                 isl_point *sample_pnt;
 198                 sample_pnt = isl_point_alloc(isl_set_get_dim(sp->empty), sample);
 199                 assert(isl_set_contains_point(sp->empty, sample_pnt));
 200                 isl_point_free(sample_pnt);
 201                 isl_vec_free(opt);
 202         } else {
 203                 isl_set *sol;
 204                 isl_set *opt_set;
 205                 opt_set = isl_set_from_basic_set(isl_basic_set_from_vec(opt));
 206                 sol = set_plug_in_parameters(isl_set_copy(sp->sol), sample);
 207                 assert(isl_set_is_equal(opt_set, sol));
 208                 isl_set_free(sol);
 209                 isl_set_free(opt_set);
 210         }
 211
 212         if (!(sp->n % sp->stride)) {
 213                 printf("o");
 214                 fflush(stdout);
 215         }
 216
 217         return sp->n >= 1 ? 0 : -1;
 218 }
 219
 220 static void check_solution(isl_basic_set *bset, isl_basic_set *context,
 221         isl_set *sol, isl_set *empty, int max)
 222 {
 223         struct isl_scan_pip sp;
 224         isl_int count, count_max;
 225         int i, n;
 226         int r;
 227
 228         context = set_bounds(context);
 229         context = isl_basic_set_underlying_set(context);
 230
 231         isl_int_init(count);
 232         isl_int_init(count_max);
 233
 234         isl_int_set_si(count_max, 2000);
 235         r = isl_basic_set_count_upto(context, count_max, &count);
 236         assert(r >= 0);
 237         n = isl_int_get_si(count);
 238
 239         isl_int_clear(count_max);
 240         isl_int_clear(count);
 241
 242         sp.callback.add = scan_one;
 243         sp.bset = bset;
 244         sp.sol = sol;
 245         sp.empty = empty;
 246         sp.n = n;
 247         sp.stride = n > 70 ? 1 + (n + 1)/70 : 1;
 248         sp.max = max;
 249
 250         for (i = 0; i < n; i += sp.stride)
 251                 printf(".");
 252         printf("\r");
 253         fflush(stdout);
 254
 255         isl_basic_set_scan(context, &sp.callback);
 256
 257         printf("\n");
 258
 259         isl_basic_set_free(bset);
 260 }
 261
 262 int main(int argc, char **argv)
 263 {
 264         struct isl_ctx *ctx;
 265         struct isl_basic_set *context, *bset, *copy, *context_copy;
 266         struct isl_set *set;
 267         struct isl_set *empty;
 268         int neg_one;
 269         char s[1024];
 270         int urs_parms = 0;
 271         int urs_unknowns = 0;
 272         int max = 0;
 273         int rational = 0;
 274         int n;
 275         struct options *options;
 276
 277         options = options_new_with_defaults();
 278         assert(options);
 279         argc = options_parse(options, argc, argv, ISL_ARG_ALL);
 280
 281         ctx = isl_ctx_alloc_with_options(options_arg, options);
 282
 283         context = isl_basic_set_read_from_file(ctx, stdin, 0);
 284         assert(context);
 285         n = fscanf(stdin, "%d", &neg_one);
 286         assert(n == 1);
 287         assert(neg_one == -1);
 288         bset = isl_basic_set_read_from_file(ctx, stdin,
 289                 isl_basic_set_dim(context, isl_dim_set));
 290
 291         while (fgets(s, sizeof(s), stdin)) {
 292                 if (strncasecmp(s, "Maximize", 8) == 0)
 293                         max = 1;
 294                 if (strncasecmp(s, "Rational", 8) == 0) {
 295                         rational = 1;
 296                         bset = isl_basic_set_set_rational(bset);
 297                 }
 298                 if (strncasecmp(s, "Urs_parms", 9) == 0)
 299                         urs_parms = 1;
 300                 if (strncasecmp(s, "Urs_unknowns", 12) == 0)
 301                         urs_unknowns = 1;
 302         }
 303         if (!urs_parms)
 304                 context = isl_basic_set_intersect(context,
 305                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(context)));
 306         context = to_parameter_domain(context);
 307         if (!urs_unknowns)
 308                 bset = isl_basic_set_intersect(bset,
 309                 isl_basic_set_positive_orthant(isl_basic_set_get_dim(bset)));
 310
 311         if (options->verify) {
 312                 copy = isl_basic_set_copy(bset);
 313                 context_copy = isl_basic_set_copy(context);
 314         }
 315
 316         if (max)
 317                 set = isl_basic_set_partial_lexmax(bset, context, &empty);
 318         else
 319                 set = isl_basic_set_partial_lexmin(bset, context, &empty);
 320
 321         if (options->verify) {
 322                 assert(!rational);
 323                 check_solution(copy, context_copy, set, empty, max);
 324         } else {
 325                 isl_set_print(set, stdout, 0, ISL_FORMAT_ISL);
 326                 fprintf(stdout, "\n");
 327                 fprintf(stdout, "no solution: ");
 328                 isl_set_print(empty, stdout, 0, ISL_FORMAT_ISL);
 329                 fprintf(stdout, "\n");
 330         }
 331
 332         isl_set_free(set);
 333         isl_set_free(empty);
 334         isl_ctx_free(ctx);
 335
 336         return 0;
 337 }