nsz Git - libfirm/blob - heuristical.c

   1 #include "adt/array.h"
   2 #include "assert.h"
   3 #include "error.h"
   4
   5 #include "heuristical.h"
   6 #include "html_dumper.h"
   7 #include "kaps.h"
   8 #include "matrix.h"
   9 #include "pbqp_edge.h"
  10 #include "pbqp_edge_t.h"
  11 #include "pbqp_node.h"
  12 #include "pbqp_node_t.h"
  13 #include "vector.h"
  14
  15 static pbqp_edge **edge_bucket;
  16 static pbqp_node **node_buckets[4];
  17 static pbqp_node **reduced_bucket = NULL;
  18 static int         buckets_filled = 0;
  19
  20 static num add(num x, num y)
  21 {
  22         if (x == INF_COSTS || y == INF_COSTS) return INF_COSTS;
  23
  24         return x + y;
  25 }
  26
  27 static void init_buckets(void)
  28 {
  29         int i;
  30
  31         edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
  32         reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
  33
  34         for (i = 0; i < 4; ++i) {
  35                 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
  36         }
  37 }
  38
  39 static void fill_node_buckets(pbqp *pbqp)
  40 {
  41         unsigned node_index;
  42         unsigned node_len;
  43
  44         assert(pbqp);
  45         node_len = pbqp->num_nodes;
  46
  47         for (node_index = 0; node_index < node_len; ++node_index) {
  48                 unsigned   arity;
  49                 pbqp_node *node = get_node(pbqp, node_index);
  50
  51                 if (!node) continue;
  52
  53                 arity = ARR_LEN(node->edges);
  54
  55                 /* We have only one bucket for nodes with arity >= 3. */
  56                 if (arity > 3) {
  57                         arity = 3;
  58                 }
  59
  60                 node->bucket_index = ARR_LEN(node_buckets[arity]);
  61
  62                 ARR_APP1(pbqp_node *, node_buckets[arity], node);
  63         }
  64
  65         buckets_filled = 1;
  66 }
  67
  68 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
  69 {
  70         pbqp_matrix    *mat;
  71         pbqp_node      *src_node;
  72         pbqp_node      *tgt_node;
  73         vector         *src_vec;
  74         vector         *tgt_vec;
  75         int             src_len;
  76         int             tgt_len;
  77         int             src_index;
  78
  79         assert(pbqp);
  80         assert(edge);
  81
  82         src_node = edge->src;
  83         tgt_node = edge->tgt;
  84         assert(src_node);
  85         assert(tgt_node);
  86
  87         src_vec = src_node->costs;
  88         tgt_vec = tgt_node->costs;
  89         assert(src_vec);
  90         assert(tgt_vec);
  91
  92         src_len = src_vec->len;
  93         tgt_len = tgt_vec->len;
  94         assert(src_len > 0);
  95         assert(tgt_len > 0);
  96
  97         mat = edge->costs;
  98         assert(mat);
  99
 100         /* Normalize towards source node. */
 101         for (src_index = 0; src_index < src_len; ++src_index) {
 102                 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
 103
 104                 if (min != 0) {
 105                         pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
 106                         src_vec->entries[src_index].data = add(
 107                                         src_vec->entries[src_index].data, min);
 108
 109                         // TODO add to edge_list if inf
 110                 }
 111         }
 112 }
 113
 114 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
 115 {
 116         pbqp_matrix    *mat;
 117         pbqp_node      *src_node;
 118         pbqp_node      *tgt_node;
 119         vector         *src_vec;
 120         vector         *tgt_vec;
 121         int             src_len;
 122         int             tgt_len;
 123         int             tgt_index;
 124
 125         assert(pbqp);
 126         assert(edge);
 127
 128         src_node = edge->src;
 129         tgt_node = edge->tgt;
 130         assert(src_node);
 131         assert(tgt_node);
 132
 133         src_vec = src_node->costs;
 134         tgt_vec = tgt_node->costs;
 135         assert(src_vec);
 136         assert(tgt_vec);
 137
 138         src_len = src_vec->len;
 139         tgt_len = tgt_vec->len;
 140         assert(src_len > 0);
 141         assert(tgt_len > 0);
 142
 143         mat = edge->costs;
 144         assert(mat);
 145
 146         for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
 147                 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
 148
 149                 if (min != 0) {
 150                         pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
 151                         tgt_vec->entries[tgt_index].data = add(
 152                                         tgt_vec->entries[tgt_index].data, min);
 153
 154                         // TODO add to edge_list if inf
 155                 }
 156         }
 157 }
 158
 159 static void reorder_node(pbqp_node *node)
 160 {
 161         unsigned    arity;
 162         unsigned    old_arity;
 163         unsigned    old_bucket_len;
 164         unsigned    old_bucket_index;
 165         pbqp_node **old_bucket;
 166         pbqp_node  *other;
 167
 168         if (!buckets_filled) return;
 169
 170         assert(node);
 171
 172         arity = ARR_LEN(node->edges);
 173
 174         /* Same bucket as before */
 175         if (arity > 2) return;
 176
 177         /* Assume node lost one incident edge. */
 178         old_arity        = arity + 1;
 179         old_bucket       = node_buckets[old_arity];
 180         old_bucket_len   = ARR_LEN(old_bucket);
 181         old_bucket_index = node->bucket_index;
 182
 183         if (old_bucket_len <= old_bucket_index ||
 184             old_bucket[old_bucket_index] != node) {
 185                 /* Old arity is new arity, so we have nothing to do. */
 186                 assert(old_bucket_index < ARR_LEN(node_buckets[arity]) &&
 187                        node_buckets[arity][old_bucket_index] == node);
 188                 return;
 189         }
 190
 191         assert(old_bucket[old_bucket_index] == node);
 192
 193         /* Delete node from old bucket... */
 194         other                        = old_bucket[old_bucket_len - 1];
 195         other->bucket_index          = old_bucket_index;
 196         old_bucket[old_bucket_index] = other;
 197         ARR_SHRINKLEN(node_buckets[old_arity], old_bucket_len - 1);
 198
 199         /* ..and add to new one. */
 200         node->bucket_index = ARR_LEN(node_buckets[arity]);
 201         ARR_APP1(pbqp_node*, node_buckets[arity], node);
 202 }
 203
 204 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
 205 {
 206         pbqp_matrix    *mat;
 207         pbqp_node      *src_node;
 208         pbqp_node      *tgt_node;
 209         vector         *src_vec;
 210         vector         *tgt_vec;
 211         int             src_len;
 212         int             tgt_len;
 213
 214         assert(pbqp);
 215         assert(edge);
 216
 217         src_node = edge->src;
 218         tgt_node = edge->tgt;
 219         assert(src_node);
 220         assert(tgt_node);
 221
 222         if (pbqp->dump_file) {
 223                 char txt[100];
 224                 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
 225                 dump_section(pbqp->dump_file, 3, txt);
 226         }
 227
 228         src_vec = src_node->costs;
 229         tgt_vec = tgt_node->costs;
 230         assert(src_vec);
 231         assert(tgt_vec);
 232
 233         src_len = src_vec->len;
 234         tgt_len = tgt_vec->len;
 235         assert(src_len > 0);
 236         assert(tgt_len > 0);
 237
 238         mat = edge->costs;
 239         assert(mat);
 240
 241         if (pbqp->dump_file) {
 242                 fputs("Input:<br>\n", pbqp->dump_file);
 243                 dump_simplifyedge(pbqp, edge);
 244         }
 245
 246         normalize_towards_source(pbqp, edge);
 247         normalize_towards_target(pbqp, edge);
 248
 249         if (pbqp->dump_file) {
 250                 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
 251                 dump_simplifyedge(pbqp, edge);
 252         }
 253
 254         if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
 255                 if (pbqp->dump_file) {
 256                         fputs("edge has been eliminated<br>\n", pbqp->dump_file);
 257                 }
 258
 259                 delete_edge(edge);
 260                 reorder_node(src_node);
 261                 reorder_node(tgt_node);
 262         }
 263 }
 264
 265 void solve_pbqp_heuristical(pbqp *pbqp)
 266 {
 267         unsigned node_index;
 268         unsigned node_len;
 269
 270         assert(pbqp);
 271
 272         if (pbqp->dump_file) {
 273                 pbqp_dump_input(pbqp);
 274                 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
 275         }
 276
 277         node_len = pbqp->num_nodes;
 278
 279         init_buckets();
 280
 281         /* First simplify all edges. */
 282         for (node_index = 0; node_index < node_len; ++node_index) {
 283                 unsigned    edge_index;
 284                 pbqp_node  *node = get_node(pbqp, node_index);
 285                 pbqp_edge **edges;
 286                 unsigned    edge_len;
 287
 288                 if (!node) continue;
 289
 290                 edges = node->edges;
 291                 edge_len = ARR_LEN(edges);
 292
 293                 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
 294                         pbqp_edge *edge = edges[edge_index];
 295
 296                         /* Simplify only once per edge. */
 297                         if (node != edge->src) continue;
 298
 299                         simplify_edge(pbqp, edge);
 300                 }
 301         }
 302
 303         /* Put node into bucket representing their arity. */
 304         fill_node_buckets(pbqp);
 305
 306         for (;;) {
 307                 if (ARR_LEN(edge_bucket) > 0) {
 308                         panic("Please implement edge simplification");
 309                 } else if (ARR_LEN(node_buckets[1]) > 0) {
 310                         applyRI(pbqp);
 311                 } else if (ARR_LEN(node_buckets[2]) > 0) {
 312                         panic("Please implement RII simplification");
 313                 } else if (ARR_LEN(node_buckets[3]) > 0) {
 314                         panic("Please implement RN simplification");
 315                 } else {
 316                         break;
 317                 }
 318         }
 319
 320         if (pbqp->dump_file) {
 321                 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
 322                 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
 323         }
 324
 325         /* Solve trivial nodes and calculate solution. */
 326         node_len = ARR_LEN(node_buckets[0]);
 327         for (node_index = 0; node_index < node_len; ++node_index) {
 328                 pbqp_node *node = node_buckets[0][node_index];
 329                 assert(node);
 330
 331                 node->solution = vector_get_min_index(node->costs);
 332                 pbqp->solution = add(pbqp->solution,
 333                                 node->costs->entries[node->solution].data);
 334                 if (pbqp->dump_file) {
 335                         fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 336                         dump_node(pbqp, node);
 337                 }
 338         }
 339
 340         if (pbqp->dump_file) {
 341                 dump_section(pbqp->dump_file, 2, "Minimum");
 342                 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
 343                 dump_section(pbqp->dump_file, 2, "Back Propagation");
 344         }
 345
 346         /* Solve reduced nodes. */
 347         node_len = ARR_LEN(reduced_bucket);
 348         for (node_index = node_len; node_index > 0; --node_index) {
 349                 pbqp_node *node = reduced_bucket[node_index - 1];
 350                 assert(node);
 351
 352                 switch (ARR_LEN(node->edges)) {
 353                         case 1:
 354                                 back_propagate_RI(pbqp, node);
 355                                 break;
 356                         case 2:
 357                                 panic("Please implement back propagation for RII");
 358                                 break;
 359                         default:
 360                                 panic("Only nodes with degree one or two should be in this bucket");
 361                                 break;
 362                 }
 363         }
 364 }
 365
 366 void applyRI(pbqp *pbqp)
 367 {
 368         pbqp_node  **bucket     = node_buckets[1];
 369         unsigned     bucket_len = ARR_LEN(bucket);
 370         pbqp_node   *node       = bucket[bucket_len - 1];
 371         pbqp_edge   *edge       = node->edges[0];
 372         pbqp_matrix *mat        = edge->costs;
 373         int          is_src     = edge->src == node;
 374         pbqp_node   *other_node;
 375
 376         if (is_src) {
 377                 other_node = edge->tgt;
 378         } else {
 379                 other_node = edge->src;
 380         }
 381
 382         if (pbqp->dump_file) {
 383                 char     txt[100];
 384                 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
 385                 dump_section(pbqp->dump_file, 2, txt);
 386                 pbqp_dump_graph(pbqp);
 387                 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
 388                 dump_node(pbqp, node);
 389                 dump_node(pbqp, other_node);
 390                 dump_edge(pbqp, edge);
 391         }
 392
 393         if (is_src) {
 394                 pbqp_matrix_add_to_all_cols(mat, node->costs);
 395                 normalize_towards_target(pbqp, edge);
 396         } else {
 397                 pbqp_matrix_add_to_all_rows(mat, node->costs);
 398                 normalize_towards_source(pbqp, edge);
 399         }
 400         disconnect_edge(other_node, edge);
 401
 402         if (pbqp->dump_file) {
 403                 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
 404                 dump_node(pbqp, other_node);
 405         }
 406
 407         /* Remove node from bucket... */
 408         ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
 409         reorder_node(other_node);
 410
 411         /* ...and add it to back propagation list. */
 412         node->bucket_index = ARR_LEN(reduced_bucket);
 413         ARR_APP1(pbqp_node *, reduced_bucket, node);
 414 }
 415
 416 void applyRII(pbqp *pbqp)
 417 {
 418         pbqp_node  **bucket     = node_buckets[1];
 419         unsigned     bucket_len = ARR_LEN(bucket);
 420         pbqp_node   *node       = bucket[bucket_len - 1];
 421         pbqp_edge   *src_edge   = node->edges[0];
 422         pbqp_edge   *tgt_edge   = node->edges[1];
 423         int          src_is_src = src_edge->src == node;
 424         int          tgt_is_src = tgt_edge->src == node;
 425         pbqp_matrix *src_mat;
 426         pbqp_matrix *tgt_mat;
 427         pbqp_node   *src_node;
 428         pbqp_node   *tgt_node;
 429         pbqp_matrix *mat;
 430         vector      *vec;
 431         vector      *node_vec;
 432         vector      *src_vec;
 433         vector      *tgt_vec;
 434         unsigned     col_index;
 435         unsigned     col_len;
 436         unsigned     row_index;
 437         unsigned     row_len;
 438         unsigned     node_len;
 439
 440         if (src_is_src) {
 441                 src_node = src_edge->tgt;
 442         } else {
 443                 src_node = src_edge->src;
 444         }
 445
 446         if (tgt_is_src) {
 447                 tgt_node = tgt_edge->tgt;
 448         } else {
 449                 tgt_node = tgt_edge->src;
 450         }
 451
 452         /* Swap nodes if necessary. */
 453         if (tgt_node->index < src_node->index) {
 454                 pbqp_node *tmp_node;
 455                 pbqp_edge *tmp_edge;
 456
 457                 tmp_node = src_node;
 458                 src_node = tgt_node;
 459                 tgt_node = tmp_node;
 460
 461                 tmp_edge = src_edge;
 462                 src_edge = tgt_edge;
 463                 tgt_edge = tmp_edge;
 464
 465                 src_is_src = src_edge->src == node;
 466                 tgt_is_src = tgt_edge->src == node;
 467         }
 468
 469         src_mat = src_edge->costs;
 470         tgt_mat = tgt_edge->costs;
 471
 472         src_vec  = src_node->costs;
 473         tgt_vec  = tgt_node->costs;
 474         node_vec = node->costs;
 475
 476         row_len  = ARR_LEN(src_vec);
 477         col_len  = ARR_LEN(tgt_vec);
 478         node_len = ARR_LEN(node_vec);
 479
 480         mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
 481
 482         for (row_index = 0; row_index < row_len; ++row_index) {
 483                 for (col_index = 0; col_index < col_len; ++col_index) {
 484                         vec = vector_copy(pbqp, node_vec);
 485
 486                         if (src_is_src) {
 487                                 vector_add_matrix_col(vec, src_mat, row_index);
 488                         } else {
 489                                 vector_add_matrix_row(vec, src_mat, row_index);
 490                         }
 491
 492                         if (tgt_is_src) {
 493                                 vector_add_matrix_col(vec, tgt_mat, col_index);
 494                         } else {
 495                                 vector_add_matrix_row(vec, tgt_mat, col_index);
 496                         }
 497
 498                         mat->entries[row_index * col_len + col_index] = vector_get_min_index(vec);
 499                 }
 500         }
 501
 502         pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
 503
 504         if (edge == NULL) {
 505                 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
 506         } else {
 507                 pbqp_matrix_add(edge->costs, mat);
 508
 509                 /* Free local matrix. */
 510                 obstack_free(&pbqp->obstack, mat);
 511         }
 512
 513         /* Disconnect node. */
 514         disconnect_edge(src_node, src_edge);
 515         disconnect_edge(tgt_node, tgt_edge);
 516
 517         /* Edge has changed so we simplify it. */
 518         simplify_edge(pbqp, edge);
 519 }
 520
 521 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
 522 {
 523         pbqp_edge   *edge;
 524         pbqp_node   *other;
 525         pbqp_matrix *mat;
 526         vector      *vec;
 527         int          is_src;
 528
 529         assert(pbqp);
 530         assert(node);
 531
 532         edge = node->edges[0];
 533         mat = edge->costs;
 534         is_src = edge->src == node;
 535         vec = node->costs;
 536
 537         if (is_src) {
 538                 other = edge->tgt;
 539                 assert(other);
 540                 vector_add_matrix_col(vec, mat, other->solution);
 541         } else {
 542                 other = edge->src;
 543                 assert(other);
 544                 vector_add_matrix_row(vec, mat, other->solution);
 545         }
 546
 547         node->solution = vector_get_min_index(vec);
 548         if (pbqp->dump_file) {
 549                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 550         }
 551 }
 552
 553 int node_is_reduced(pbqp_node *node)
 554 {
 555         if (!reduced_bucket) return 0;
 556
 557         assert(node);
 558         if (ARR_LEN(node->edges) == 0) return 1;
 559
 560         unsigned bucket_length = ARR_LEN(reduced_bucket);
 561         unsigned bucket_index  = node->bucket_index;
 562
 563         return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;
 564 }