nsz Git - libfirm/blob - ir/kaps/brute_force.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief   Brute force PBQP solver.
  23  * @date    02.12.2008
  24  * @author  Sebastian Buchwald
  25  * @version $Id$
  26  */
  27 #include "config.h"
  28
  29 #include "assert.h"
  30 #include "error.h"
  31
  32 #include "bucket.h"
  33 #include "brute_force.h"
  34 #include "optimal.h"
  35 #if KAPS_DUMP
  36 #include "html_dumper.h"
  37 #endif
  38 #include "kaps.h"
  39 #include "matrix.h"
  40 #include "pbqp_edge.h"
  41 #include "pbqp_edge_t.h"
  42 #include "pbqp_node.h"
  43 #include "pbqp_node_t.h"
  44 #include "vector.h"
  45
  46 #if KAPS_STATISTIC
  47 static int dump = 0;
  48 #endif
  49
  50 /* Forward declarations. */
  51 static void apply_Brute_Force(pbqp_t *pbqp);
  52
  53 static void apply_brute_force_reductions(pbqp_t *pbqp)
  54 {
  55         for (;;) {
  56                 if (edge_bucket_get_length(edge_bucket) > 0) {
  57                         apply_edge(pbqp);
  58                 } else if (node_bucket_get_length(node_buckets[1]) > 0) {
  59                         apply_RI(pbqp);
  60                 } else if (node_bucket_get_length(node_buckets[2]) > 0) {
  61                         apply_RII(pbqp);
  62                 } else if (node_bucket_get_length(node_buckets[3]) > 0) {
  63                         apply_Brute_Force(pbqp);
  64                 } else {
  65                         return;
  66                 }
  67         }
  68 }
  69
  70 static unsigned get_minimal_alternative(pbqp_t *pbqp, pbqp_node_t *node)
  71 {
  72         vector_t *node_vec;
  73         unsigned  node_index;
  74         unsigned  node_len;
  75         unsigned  min_index    = 0;
  76         num       min          = INF_COSTS;
  77         unsigned  bucket_index;
  78
  79         assert(pbqp);
  80         node_vec     = node->costs;
  81         node_len     = node_vec->len;
  82         bucket_index = node->bucket_index;
  83
  84         for (node_index = 0; node_index < node_len; ++node_index) {
  85                 pbqp_node_bucket_t bucket_deg3;
  86                 num                value;
  87                 unsigned           bucket_0_length;
  88                 unsigned           bucket_red_length;
  89
  90                 char *tmp = (char*)obstack_finish(&pbqp->obstack);
  91
  92                 node_bucket_init(&bucket_deg3);
  93
  94                 /* Some node buckets and the edge bucket should be empty. */
  95                 assert(node_bucket_get_length(node_buckets[1]) == 0);
  96                 assert(node_bucket_get_length(node_buckets[2]) == 0);
  97                 assert(edge_bucket_get_length(edge_bucket)     == 0);
  98
  99                 /* char *tmp = obstack_finish(&pbqp->obstack); */
 100
 101                 /* Save current PBQP state. */
 102                 node_bucket_copy(&bucket_deg3, node_buckets[3]);
 103                 node_bucket_shrink(&node_buckets[3], 0);
 104                 node_bucket_deep_copy(pbqp, &node_buckets[3], bucket_deg3);
 105                 node_bucket_update(pbqp, node_buckets[3]);
 106                 bucket_0_length   = node_bucket_get_length(node_buckets[0]);
 107                 bucket_red_length = node_bucket_get_length(reduced_bucket);
 108
 109                 /* Select alternative and solve PBQP recursively. */
 110                 select_alternative(node_buckets[3][bucket_index], node_index);
 111                 apply_brute_force_reductions(pbqp);
 112
 113                 value = determine_solution(pbqp);
 114
 115                 if (value < min) {
 116                         min = value;
 117                         min_index = node_index;
 118                 }
 119
 120                 /* Some node buckets and the edge bucket should still be empty. */
 121                 assert(node_bucket_get_length(node_buckets[1]) == 0);
 122                 assert(node_bucket_get_length(node_buckets[2]) == 0);
 123                 assert(edge_bucket_get_length(edge_bucket)     == 0);
 124
 125                 /* Clear modified buckets... */
 126                 node_bucket_shrink(&node_buckets[3], 0);
 127
 128                 /* ... and restore old PBQP state. */
 129                 node_bucket_shrink(&node_buckets[0], bucket_0_length);
 130                 node_bucket_shrink(&reduced_bucket, bucket_red_length);
 131                 node_bucket_copy(&node_buckets[3], bucket_deg3);
 132                 node_bucket_update(pbqp, node_buckets[3]);
 133
 134                 /* Free copies. */
 135                 /* obstack_free(&pbqp->obstack, tmp); */
 136                 node_bucket_free(&bucket_deg3);
 137
 138                 obstack_free(&pbqp->obstack, tmp);
 139         }
 140
 141         return min_index;
 142 }
 143
 144 static void apply_Brute_Force(pbqp_t *pbqp)
 145 {
 146         pbqp_node_t *node         = NULL;
 147         unsigned     min_index    = 0;
 148
 149         assert(pbqp);
 150
 151         /* We want to reduce a node with maximum degree. */
 152         node = get_node_with_max_degree();
 153         assert(pbqp_node_get_degree(node) > 2);
 154
 155 #if KAPS_DUMP
 156         if (pbqp->dump_file) {
 157                 char     txt[100];
 158                 sprintf(txt, "BF-Reduction of Node n%d", node->index);
 159                 dump_section(pbqp->dump_file, 2, txt);
 160                 pbqp_dump_graph(pbqp);
 161         }
 162 #endif
 163
 164 #if KAPS_STATISTIC
 165         dump++;
 166 #endif
 167
 168         min_index = get_minimal_alternative(pbqp, node);
 169         node = pbqp->nodes[node->index];
 170
 171 #if KAPS_DUMP
 172         if (pbqp->dump_file) {
 173                 fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
 174                                         node->index, min_index);
 175         }
 176 #endif
 177
 178 #if KAPS_STATISTIC
 179         dump--;
 180         if (dump == 0) {
 181                 FILE *fh = fopen("solutions.pb", "a");
 182                 fprintf(fh, "[%u]", min_index);
 183                 fclose(fh);
 184                 pbqp->num_bf++;
 185         }
 186 #endif
 187
 188         /* Now that we found the minimum set all other costs to infinity. */
 189         select_alternative(node, min_index);
 190 }
 191
 192
 193
 194 static void back_propagate_RI(pbqp_t *pbqp, pbqp_node_t *node)
 195 {
 196         pbqp_edge_t   *edge;
 197         pbqp_node_t   *other;
 198         pbqp_matrix_t *mat;
 199         vector_t      *vec;
 200         int            is_src;
 201
 202         assert(pbqp);
 203
 204         edge = node->edges[0];
 205         mat = edge->costs;
 206         is_src = edge->src == node;
 207         vec = node->costs;
 208
 209         if (is_src) {
 210                 other = edge->tgt;
 211
 212                 /* Update pointer for brute force solver. */
 213                 other = pbqp->nodes[other->index];
 214
 215                 node->solution = pbqp_matrix_get_col_min_index(mat, other->solution, vec);
 216         } else {
 217                 other = edge->src;
 218
 219                 /* Update pointer for brute force solver. */
 220                 other = pbqp->nodes[other->index];
 221
 222                 node->solution = pbqp_matrix_get_row_min_index(mat, other->solution, vec);
 223         }
 224
 225 #if KAPS_DUMP
 226         if (pbqp->dump_file) {
 227                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 228         }
 229 #endif
 230 }
 231
 232 static void back_propagate_RII(pbqp_t *pbqp, pbqp_node_t *node)
 233 {
 234         pbqp_edge_t   *src_edge   = node->edges[0];
 235         pbqp_edge_t   *tgt_edge   = node->edges[1];
 236         int            src_is_src = src_edge->src == node;
 237         int            tgt_is_src = tgt_edge->src == node;
 238         pbqp_matrix_t *src_mat;
 239         pbqp_matrix_t *tgt_mat;
 240         pbqp_node_t   *src_node;
 241         pbqp_node_t   *tgt_node;
 242         vector_t      *vec;
 243         vector_t      *node_vec;
 244         unsigned       col_index;
 245         unsigned       row_index;
 246
 247         assert(pbqp);
 248
 249         if (src_is_src) {
 250                 src_node = src_edge->tgt;
 251         } else {
 252                 src_node = src_edge->src;
 253         }
 254
 255         if (tgt_is_src) {
 256                 tgt_node = tgt_edge->tgt;
 257         } else {
 258                 tgt_node = tgt_edge->src;
 259         }
 260
 261         /* Swap nodes if necessary. */
 262         if (tgt_node->index < src_node->index) {
 263                 pbqp_node_t *tmp_node;
 264                 pbqp_edge_t *tmp_edge;
 265
 266                 tmp_node = src_node;
 267                 src_node = tgt_node;
 268                 tgt_node = tmp_node;
 269
 270                 tmp_edge = src_edge;
 271                 src_edge = tgt_edge;
 272                 tgt_edge = tmp_edge;
 273
 274                 src_is_src = src_edge->src == node;
 275                 tgt_is_src = tgt_edge->src == node;
 276         }
 277
 278         /* Update pointer for brute force solver. */
 279         src_node = pbqp->nodes[src_node->index];
 280         tgt_node = pbqp->nodes[tgt_node->index];
 281
 282         src_mat = src_edge->costs;
 283         tgt_mat = tgt_edge->costs;
 284
 285         node_vec = node->costs;
 286
 287         row_index = src_node->solution;
 288         col_index = tgt_node->solution;
 289
 290         vec = vector_copy(pbqp, node_vec);
 291
 292         if (src_is_src) {
 293                 vector_add_matrix_col(vec, src_mat, row_index);
 294         } else {
 295                 vector_add_matrix_row(vec, src_mat, row_index);
 296         }
 297
 298         if (tgt_is_src) {
 299                 vector_add_matrix_col(vec, tgt_mat, col_index);
 300         } else {
 301                 vector_add_matrix_row(vec, tgt_mat, col_index);
 302         }
 303
 304         node->solution = vector_get_min_index(vec);
 305
 306 #if KAPS_DUMP
 307         if (pbqp->dump_file) {
 308                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 309         }
 310 #endif
 311
 312         obstack_free(&pbqp->obstack, vec);
 313 }
 314
 315 static void back_propagate_brute_force(pbqp_t *pbqp)
 316 {
 317         unsigned node_index;
 318         unsigned node_len = node_bucket_get_length(reduced_bucket);
 319
 320         assert(pbqp);
 321
 322 #if KAPS_DUMP
 323         if (pbqp->dump_file) {
 324                 dump_section(pbqp->dump_file, 2, "Back Propagation");
 325         }
 326 #endif
 327
 328         for (node_index = node_len; node_index > 0; --node_index) {
 329                 pbqp_node_t *node = reduced_bucket[node_index - 1];
 330
 331                 switch (pbqp_node_get_degree(node)) {
 332                         case 1:
 333                                 back_propagate_RI(pbqp, node);
 334                                 break;
 335                         case 2:
 336                                 back_propagate_RII(pbqp, node);
 337                                 break;
 338                         default:
 339                                 panic("Only nodes with degree one or two should be in this bucket");
 340                                 break;
 341                 }
 342         }
 343 }
 344
 345 void solve_pbqp_brute_force(pbqp_t *pbqp)
 346 {
 347         /* Reduce nodes degree ... */
 348         initial_simplify_edges(pbqp);
 349
 350         /* ... and put node into bucket representing their degree. */
 351         fill_node_buckets(pbqp);
 352
 353 #if KAPS_STATISTIC
 354         FILE *fh = fopen("solutions.pb", "a");
 355         fprintf(fh, "Solution");
 356         fclose(fh);
 357 #endif
 358
 359         apply_brute_force_reductions(pbqp);
 360
 361         pbqp->solution = determine_solution(pbqp);
 362
 363 #if KAPS_STATISTIC
 364         fh = fopen("solutions.pb", "a");
 365         #if KAPS_USE_UNSIGNED
 366                 fprintf(fh, ": %u RE:%u R0:%u R1:%u R2:%u RM:%u RN/BF:%u\n", pbqp->solution,
 367                                 pbqp->num_edges, pbqp->num_r0, pbqp->num_r1, pbqp->num_r2,
 368                                 pbqp->num_rm, pbqp->num_rn);
 369         #else
 370                 fprintf(fh, ": %lld RE:%u R0:%u R1:%u R2:%u RM:%u RN/BF:%u\n", pbqp->solution,
 371                                 pbqp->num_edges, pbqp->num_r0, pbqp->num_r1, pbqp->num_r2,
 372                                 pbqp->num_rm, pbqp->num_bf);
 373         #endif
 374         fclose(fh);
 375 #endif
 376
 377         /* Solve reduced nodes. */
 378         back_propagate_brute_force(pbqp);
 379
 380         free_buckets();
 381 }