nsz Git - libfirm/blob - 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 /* Forward declarations. */
  47 static void apply_Brute_Force(pbqp *pbqp);
  48
  49 static void apply_brute_force_reductions(pbqp *pbqp)
  50 {
  51         for (;;) {
  52                 if (edge_bucket_get_length(edge_bucket) > 0) {
  53                         apply_edge(pbqp);
  54                 } else if (node_bucket_get_length(node_buckets[1]) > 0) {
  55                         apply_RI(pbqp);
  56                 } else if (node_bucket_get_length(node_buckets[2]) > 0) {
  57                         apply_RII(pbqp);
  58                 } else if (node_bucket_get_length(node_buckets[3]) > 0) {
  59                         apply_Brute_Force(pbqp);
  60                 } else {
  61                         return;
  62                 }
  63         }
  64 }
  65
  66 static unsigned get_minimal_alternative(pbqp *pbqp, pbqp_node *node)
  67 {
  68         vector      *node_vec;
  69         unsigned     node_index;
  70         unsigned     node_len;
  71         unsigned     min_index    = 0;
  72         num          min          = INF_COSTS;
  73         unsigned     bucket_index;
  74
  75         assert(pbqp);
  76         assert(node);
  77         node_vec     = node->costs;
  78         node_len     = node_vec->len;
  79         bucket_index = node->bucket_index;
  80
  81         for (node_index = 0; node_index < node_len; ++node_index) {
  82                 pbqp_node_bucket bucket_deg3;
  83                 num              value;
  84                 unsigned         bucket_0_length;
  85                 unsigned         bucket_red_length;
  86
  87                 char *tmp = obstack_finish(&pbqp->obstack);
  88
  89                 node_bucket_init(&bucket_deg3);
  90
  91                 /* Some node buckets and the edge bucket should be empty. */
  92                 assert(node_bucket_get_length(node_buckets[1]) == 0);
  93                 assert(node_bucket_get_length(node_buckets[2]) == 0);
  94                 assert(edge_bucket_get_length(edge_bucket)     == 0);
  95
  96                 /* char *tmp = obstack_finish(&pbqp->obstack); */
  97
  98                 /* Save current PBQP state. */
  99                 node_bucket_copy(&bucket_deg3, node_buckets[3]);
 100                 node_bucket_shrink(&node_buckets[3], 0);
 101                 node_bucket_deep_copy(pbqp, &node_buckets[3], bucket_deg3);
 102                 node_bucket_update(pbqp, node_buckets[3]);
 103                 bucket_0_length   = node_bucket_get_length(node_buckets[0]);
 104                 bucket_red_length = node_bucket_get_length(reduced_bucket);
 105
 106                 /* Select alternative and solve PBQP recursively. */
 107                 select_alternative(node_buckets[3][bucket_index], node_index);
 108                 apply_brute_force_reductions(pbqp);
 109
 110                 value = determine_solution(pbqp);
 111
 112                 if (value < min) {
 113                         min = value;
 114                         min_index = node_index;
 115                 }
 116
 117                 /* Some node buckets and the edge bucket should still be empty. */
 118                 assert(node_bucket_get_length(node_buckets[1]) == 0);
 119                 assert(node_bucket_get_length(node_buckets[2]) == 0);
 120                 assert(edge_bucket_get_length(edge_bucket)     == 0);
 121
 122                 /* Clear modified buckets... */
 123                 node_bucket_shrink(&node_buckets[3], 0);
 124
 125                 /* ... and restore old PBQP state. */
 126                 node_bucket_shrink(&node_buckets[0], bucket_0_length);
 127                 node_bucket_shrink(&reduced_bucket, bucket_red_length);
 128                 node_bucket_copy(&node_buckets[3], bucket_deg3);
 129                 node_bucket_update(pbqp, node_buckets[3]);
 130
 131                 /* Free copies. */
 132                 /* obstack_free(&pbqp->obstack, tmp); */
 133                 node_bucket_free(&bucket_deg3);
 134
 135                 obstack_free(&pbqp->obstack, tmp);
 136         }
 137
 138         return min_index;
 139 }
 140
 141 static void apply_Brute_Force(pbqp *pbqp)
 142 {
 143         pbqp_node   *node         = NULL;
 144         unsigned     min_index    = 0;
 145
 146         assert(pbqp);
 147
 148         /* We want to reduce a node with maximum degree. */
 149         node = get_node_with_max_degree();
 150         assert(node);
 151         assert(pbqp_node_get_degree(node) > 2);
 152
 153 #if     KAPS_DUMP
 154         if (pbqp->dump_file) {
 155                 char     txt[100];
 156                 sprintf(txt, "BF-Reduction of Node n%d", node->index);
 157                 dump_section(pbqp->dump_file, 2, txt);
 158                 pbqp_dump_graph(pbqp);
 159         }
 160 #endif
 161
 162 #if KAPS_STATISTIC
 163         dump++;
 164 #endif
 165
 166         min_index = get_minimal_alternative(pbqp, node);
 167         node = pbqp->nodes[node->index];
 168
 169 #if     KAPS_DUMP
 170         if (pbqp->dump_file) {
 171                 fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
 172                                         node->index, min_index);
 173         }
 174 #endif
 175
 176 #if KAPS_STATISTIC
 177         dump--;
 178         if (dump == 0) {
 179                 FILE *fh = fopen("solutions.pb", "a");
 180                 fprintf(fh, "[%u]", min_index);
 181                 fclose(fh);
 182                 pbqp->num_bf++;
 183         }
 184 #endif
 185
 186         /* Now that we found the minimum set all other costs to infinity. */
 187         select_alternative(node, min_index);
 188 }
 189
 190
 191
 192 static void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
 193 {
 194         pbqp_edge   *edge;
 195         pbqp_node   *other;
 196         pbqp_matrix *mat;
 197         vector      *vec;
 198         int          is_src;
 199
 200         assert(pbqp);
 201         assert(node);
 202
 203         edge = node->edges[0];
 204         mat = edge->costs;
 205         is_src = edge->src == node;
 206         vec = node->costs;
 207
 208         if (is_src) {
 209                 other = edge->tgt;
 210                 assert(other);
 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                 assert(other);
 219
 220                 /* Update pointer for brute force solver. */
 221                 other = pbqp->nodes[other->index];
 222
 223                 node->solution = pbqp_matrix_get_row_min_index(mat, other->solution, vec);
 224         }
 225
 226 #if     KAPS_DUMP
 227         if (pbqp->dump_file) {
 228                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 229         }
 230 #endif
 231 }
 232
 233 static void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
 234 {
 235         pbqp_edge   *src_edge   = node->edges[0];
 236         pbqp_edge   *tgt_edge   = node->edges[1];
 237         int          src_is_src = src_edge->src == node;
 238         int          tgt_is_src = tgt_edge->src == node;
 239         pbqp_matrix *src_mat;
 240         pbqp_matrix *tgt_mat;
 241         pbqp_node   *src_node;
 242         pbqp_node   *tgt_node;
 243         vector      *vec;
 244         vector      *node_vec;
 245         unsigned     col_index;
 246         unsigned     row_index;
 247
 248         assert(pbqp);
 249
 250         if (src_is_src) {
 251                 src_node = src_edge->tgt;
 252         } else {
 253                 src_node = src_edge->src;
 254         }
 255
 256         if (tgt_is_src) {
 257                 tgt_node = tgt_edge->tgt;
 258         } else {
 259                 tgt_node = tgt_edge->src;
 260         }
 261
 262         /* Swap nodes if necessary. */
 263         if (tgt_node->index < src_node->index) {
 264                 pbqp_node *tmp_node;
 265                 pbqp_edge *tmp_edge;
 266
 267                 tmp_node = src_node;
 268                 src_node = tgt_node;
 269                 tgt_node = tmp_node;
 270
 271                 tmp_edge = src_edge;
 272                 src_edge = tgt_edge;
 273                 tgt_edge = tmp_edge;
 274
 275                 src_is_src = src_edge->src == node;
 276                 tgt_is_src = tgt_edge->src == node;
 277         }
 278
 279         /* Update pointer for brute force solver. */
 280         src_node = pbqp->nodes[src_node->index];
 281         tgt_node = pbqp->nodes[tgt_node->index];
 282
 283         src_mat = src_edge->costs;
 284         tgt_mat = tgt_edge->costs;
 285
 286         node_vec = node->costs;
 287
 288         row_index = src_node->solution;
 289         col_index = tgt_node->solution;
 290
 291         vec = vector_copy(pbqp, node_vec);
 292
 293         if (src_is_src) {
 294                 vector_add_matrix_col(vec, src_mat, row_index);
 295         } else {
 296                 vector_add_matrix_row(vec, src_mat, row_index);
 297         }
 298
 299         if (tgt_is_src) {
 300                 vector_add_matrix_col(vec, tgt_mat, col_index);
 301         } else {
 302                 vector_add_matrix_row(vec, tgt_mat, col_index);
 303         }
 304
 305         node->solution = vector_get_min_index(vec);
 306
 307 #if     KAPS_DUMP
 308         if (pbqp->dump_file) {
 309                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 310         }
 311 #endif
 312
 313         obstack_free(&pbqp->obstack, vec);
 314 }
 315
 316 static void back_propagate_brute_force(pbqp *pbqp)
 317 {
 318         unsigned node_index;
 319         unsigned node_len   = node_bucket_get_length(reduced_bucket);
 320
 321         assert(pbqp);
 322
 323 #if     KAPS_DUMP
 324         if (pbqp->dump_file) {
 325                 dump_section(pbqp->dump_file, 2, "Back Propagation");
 326         }
 327 #endif
 328
 329         for (node_index = node_len; node_index > 0; --node_index) {
 330                 pbqp_node *node = reduced_bucket[node_index - 1];
 331
 332                 switch (pbqp_node_get_degree(node)) {
 333                         case 1:
 334                                 back_propagate_RI(pbqp, node);
 335                                 break;
 336                         case 2:
 337                                 back_propagate_RII(pbqp, node);
 338                                 break;
 339                         default:
 340                                 panic("Only nodes with degree one or two should be in this bucket");
 341                                 break;
 342                 }
 343         }
 344 }
 345
 346 void solve_pbqp_brute_force(pbqp *pbqp)
 347 {
 348         /* Reduce nodes degree ... */
 349         initial_simplify_edges(pbqp);
 350
 351         /* ... and put node into bucket representing their degree. */
 352         fill_node_buckets(pbqp);
 353
 354 #if KAPS_STATISTIC
 355         FILE *fh = fopen("solutions.pb", "a");
 356         fprintf(fh, "Solution");
 357         fclose(fh);
 358 #endif
 359
 360         apply_brute_force_reductions(pbqp);
 361
 362         pbqp->solution = determine_solution(pbqp);
 363
 364 #if KAPS_STATISTIC
 365         fh = fopen("solutions.pb", "a");
 366         fprintf(fh, ": %lld RE:%u R0:%u R1:%u R2:%u RN/BF:%u\n", pbqp->solution,
 367                         pbqp->num_edges, pbqp->num_r0, pbqp->num_r1, pbqp->num_r2,
 368                         pbqp->num_bf);
 369         fclose(fh);
 370 #endif
 371
 372         /* Solve reduced nodes. */
 373         back_propagate_brute_force(pbqp);
 374
 375         free_buckets();
 376 }