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
 165         if (!buckets_filled) return;
 166
 167         assert(node);
 168
 169         arity = ARR_LEN(node->edges);
 170
 171         /* Equal bucket as before */
 172         if (arity > 2) return;
 173
 174         /* Assume node lost one incident edge. */
 175         old_arity = arity + 1;
 176
 177         if (ARR_LEN(node_buckets[old_arity]) <= (int)node->bucket_index
 178                         || node_buckets[old_arity][node->bucket_index] != node) {
 179                 /* Old arity is new arity, so we have nothing to do. */
 180                 return;
 181         }
 182
 183         old_bucket_len = ARR_LEN(node_buckets[old_arity]);
 184         assert (node_buckets[old_arity][node->bucket_index] == node);
 185
 186         /* Delete node from old bucket... */
 187         node_buckets[old_arity][old_bucket_len - 1]->bucket_index
 188                         = node->bucket_index;
 189         node_buckets[old_arity][node->bucket_index]
 190                         = node_buckets[old_arity][old_bucket_len - 1];
 191         ARR_SHRINKLEN(node_buckets[old_arity], (int)old_bucket_len - 1);
 192
 193         /* ..and add to new one. */
 194         node->bucket_index = ARR_LEN(node_buckets[arity]);
 195         ARR_APP1(pbqp_node *, node_buckets[arity], node);
 196 }
 197
 198 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
 199 {
 200         pbqp_matrix    *mat;
 201         pbqp_node      *src_node;
 202         pbqp_node      *tgt_node;
 203         vector         *src_vec;
 204         vector         *tgt_vec;
 205         int             src_len;
 206         int             tgt_len;
 207
 208         assert(pbqp);
 209         assert(edge);
 210
 211         src_node = edge->src;
 212         tgt_node = edge->tgt;
 213         assert(src_node);
 214         assert(tgt_node);
 215
 216         if(pbqp->dump_file) {
 217                 char txt[100];
 218                 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
 219                 dump_section(pbqp->dump_file, 3, txt);
 220         }
 221
 222         src_vec = src_node->costs;
 223         tgt_vec = tgt_node->costs;
 224         assert(src_vec);
 225         assert(tgt_vec);
 226
 227         src_len = src_vec->len;
 228         tgt_len = tgt_vec->len;
 229         assert(src_len > 0);
 230         assert(tgt_len > 0);
 231
 232         mat = edge->costs;
 233         assert(mat);
 234
 235         if (pbqp->dump_file) {
 236                 fputs("Input:<br>\n", pbqp->dump_file);
 237                 dump_simplifyedge(pbqp, edge);
 238         }
 239
 240         normalize_towards_source(pbqp, edge);
 241         normalize_towards_target(pbqp, edge);
 242
 243         if (pbqp->dump_file) {
 244                 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
 245                 dump_simplifyedge(pbqp, edge);
 246         }
 247
 248         if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
 249                 if (pbqp->dump_file) {
 250                         fputs("edge has been eliminated", pbqp->dump_file);
 251
 252                         delete_edge(edge);
 253                         reorder_node(src_node);
 254                         reorder_node(tgt_node);
 255                 }
 256         }
 257 }
 258
 259 void solve_pbqp_heuristical(pbqp *pbqp)
 260 {
 261         unsigned node_index;
 262         unsigned node_len;
 263
 264         assert(pbqp);
 265
 266         if (pbqp->dump_file) {
 267                 pbqp_dump_input(pbqp);
 268                 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
 269         }
 270
 271         node_len = pbqp->num_nodes;
 272
 273         init_buckets();
 274
 275         /* First simplify all edges. */
 276         for (node_index = 0; node_index < node_len; ++node_index) {
 277                 unsigned    edge_index;
 278                 pbqp_node  *node = get_node(pbqp, node_index);
 279                 pbqp_edge **edges;
 280                 unsigned    edge_len;
 281
 282                 if (!node) continue;
 283
 284                 edges = node->edges;
 285                 edge_len = ARR_LEN(edges);
 286
 287                 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
 288                         pbqp_edge *edge = edges[edge_index];
 289
 290                         /* Simplify only once per edge. */
 291                         if (node != edge->src) continue;
 292
 293                         simplify_edge(pbqp, edge);
 294                 }
 295         }
 296
 297         /* Put node into bucket representing their arity. */
 298         fill_node_buckets(pbqp);
 299
 300         for (;;) {
 301                 if (ARR_LEN(edge_bucket) > 0) {
 302                         panic("Please implement edge simplification");
 303                 } else if (ARR_LEN(node_buckets[1]) > 0) {
 304                         applyRI(pbqp);
 305                 } else if (ARR_LEN(node_buckets[2]) > 0) {
 306                         panic("Please implement RII simplification");
 307                 } else if (ARR_LEN(node_buckets[3]) > 0) {
 308                         panic("Please implement RN simplification");
 309                 } else {
 310                         break;
 311                 }
 312         }
 313
 314         if (pbqp->dump_file) {
 315                 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
 316                 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
 317         }
 318
 319         /* Solve trivial nodes and calculate solution. */
 320         node_len = ARR_LEN(node_buckets[0]);
 321         for (node_index = 0; node_index < node_len; ++node_index) {
 322                 pbqp_node *node = node_buckets[0][node_index];
 323                 assert(node);
 324
 325                 node->solution = vector_get_min_index(node->costs);
 326                 pbqp->solution = add(pbqp->solution,
 327                                 node->costs->entries[node->solution].data);
 328                 if (pbqp->dump_file) {
 329                         fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 330                         dump_node(pbqp, node);
 331                 }
 332         }
 333
 334         if (pbqp->dump_file) {
 335                 dump_section(pbqp->dump_file, 2, "Minimum");
 336                 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
 337                 dump_section(pbqp->dump_file, 2, "Back Propagation");
 338         }
 339
 340         /* Solve reduced nodes. */
 341         node_len = ARR_LEN(reduced_bucket);
 342         for (node_index = node_len; node_index > 0; --node_index) {
 343                 pbqp_node *node = reduced_bucket[node_index - 1];
 344                 assert(node);
 345
 346                 switch (ARR_LEN(node->edges)) {
 347                         case 1:
 348                                 back_propagate_RI(pbqp, node);
 349                                 break;
 350                         case 2:
 351                                 panic("Please implement back propagation for RII");
 352                                 break;
 353                         default:
 354                                 panic("Only nodes with degree one or two should be in this bucket");
 355                                 break;
 356                 }
 357         }
 358 }
 359
 360 void applyRI(pbqp *pbqp)
 361 {
 362         pbqp_node  **bucket     = node_buckets[1];
 363         unsigned     bucket_len = ARR_LEN(bucket);
 364         pbqp_node   *node       = bucket[bucket_len - 1];
 365         pbqp_edge   *edge       = node->edges[0];
 366         pbqp_matrix *mat        = edge->costs;
 367         int          is_src     = edge->src == node;
 368         pbqp_node   *other_node;
 369
 370         if (is_src) {
 371                 other_node = edge->tgt;
 372         } else {
 373                 other_node = edge->src;
 374         }
 375
 376         if (pbqp->dump_file) {
 377                 char     txt[100];
 378                 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
 379                 dump_section(pbqp->dump_file, 2, txt);
 380                 pbqp_dump_graph(pbqp);
 381                 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
 382                 dump_node(pbqp, node);
 383                 dump_node(pbqp, other_node);
 384                 dump_edge(pbqp, edge);
 385         }
 386
 387         if (is_src) {
 388                 pbqp_matrix_add_to_all_cols(mat, node->costs);
 389                 normalize_towards_target(pbqp, edge);
 390         } else {
 391                 pbqp_matrix_add_to_all_rows(mat, node->costs);
 392                 normalize_towards_source(pbqp, edge);
 393         }
 394         disconnect_edge(other_node, edge);
 395
 396         if (pbqp->dump_file) {
 397                 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
 398                 dump_node(pbqp, other_node);
 399         }
 400
 401         /* Remove node from bucket... */
 402         ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
 403         reorder_node(other_node);
 404
 405         /* ...and add it to back propagation list. */
 406         node->bucket_index = ARR_LEN(reduced_bucket);
 407         ARR_APP1(pbqp_node *, reduced_bucket, node);
 408 }
 409
 410 void applyRII(pbqp *pbqp)
 411 {
 412         pbqp_node  **bucket     = node_buckets[1];
 413         unsigned     bucket_len = ARR_LEN(bucket);
 414         pbqp_node   *node       = bucket[bucket_len - 1];
 415         pbqp_edge   *src_edge   = node->edges[0];
 416         pbqp_edge   *tgt_edge   = node->edges[1];
 417         int          src_is_src = src_edge->src == node;
 418         int          tgt_is_src = tgt_edge->src == node;
 419         pbqp_matrix *src_mat;
 420         pbqp_matrix *tgt_mat;
 421         pbqp_node   *src_node;
 422         pbqp_node   *tgt_node;
 423         pbqp_matrix *mat;
 424         vector      *vec;
 425         vector      *node_vec;
 426         vector      *src_vec;
 427         vector      *tgt_vec;
 428         unsigned     col_index;
 429         unsigned     col_len;
 430         unsigned     row_index;
 431         unsigned     row_len;
 432         unsigned     node_len;
 433
 434         if (src_is_src) {
 435                 src_node = src_edge->tgt;
 436         } else {
 437                 src_node = src_edge->src;
 438         }
 439
 440         if (tgt_is_src) {
 441                 tgt_node = tgt_edge->tgt;
 442         } else {
 443                 tgt_node = tgt_edge->src;
 444         }
 445
 446         /* Swap nodes if necessary. */
 447         if (tgt_node->index < src_node->index) {
 448                 pbqp_node *tmp_node;
 449                 pbqp_edge *tmp_edge;
 450
 451                 tmp_node = src_node;
 452                 src_node = tgt_node;
 453                 tgt_node = tmp_node;
 454
 455                 tmp_edge = src_edge;
 456                 src_edge = tgt_edge;
 457                 tgt_edge = tmp_edge;
 458
 459                 src_is_src = src_edge->src == node;
 460                 tgt_is_src = tgt_edge->src == node;
 461         }
 462
 463         src_mat = src_edge->costs;
 464         tgt_mat = tgt_edge->costs;
 465
 466         src_vec  = src_node->costs;
 467         tgt_vec  = tgt_node->costs;
 468         node_vec = node->costs;
 469
 470         row_len  = ARR_LEN(src_vec);
 471         col_len  = ARR_LEN(tgt_vec);
 472         node_len = ARR_LEN(node_vec);
 473
 474         mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
 475
 476         for (row_index = 0; row_index < row_len; ++row_index) {
 477                 for (col_index = 0; col_index < col_len; ++col_index) {
 478                         vec = vector_copy(pbqp, node_vec);
 479
 480                         if (src_is_src) {
 481                                 vector_add_matrix_col(vec, src_mat, row_index);
 482                         } else {
 483                                 vector_add_matrix_row(vec, src_mat, row_index);
 484                         }
 485
 486                         if (tgt_is_src) {
 487                                 vector_add_matrix_col(vec, tgt_mat, col_index);
 488                         } else {
 489                                 vector_add_matrix_row(vec, tgt_mat, col_index);
 490                         }
 491
 492                         mat->entries[row_index * col_len + col_index] = vector_get_min_index(vec);
 493                 }
 494         }
 495
 496         pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
 497
 498         if (edge == NULL) {
 499                 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
 500         } else {
 501                 pbqp_matrix_add(edge->costs, mat);
 502
 503                 /* Free local matrix. */
 504                 obstack_free(&pbqp->obstack, mat);
 505         }
 506
 507         /* Disconnect node. */
 508         disconnect_edge(src_node, src_edge);
 509         disconnect_edge(tgt_node, tgt_edge);
 510
 511         /* Edge has changed so we simplify it. */
 512         simplify_edge(pbqp, edge);
 513 }
 514
 515 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
 516 {
 517         pbqp_edge   *edge;
 518         pbqp_node   *other;
 519         pbqp_matrix *mat;
 520         vector      *vec;
 521         int          is_src;
 522
 523         assert(pbqp);
 524         assert(node);
 525
 526         edge = node->edges[0];
 527         mat = edge->costs;
 528         is_src = edge->src == node;
 529         vec = node->costs;
 530
 531         if (is_src) {
 532                 other = edge->tgt;
 533                 assert(other);
 534                 vector_add_matrix_col(vec, mat, other->solution);
 535         } else {
 536                 other = edge->src;
 537                 assert(other);
 538                 vector_add_matrix_row(vec, mat, other->solution);
 539         }
 540
 541         node->solution = vector_get_min_index(vec);
 542         if (pbqp->dump_file) {
 543                 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
 544         }
 545 }
 546
 547 int node_is_reduced(pbqp_node *node)
 548 {
 549         if (!reduced_bucket) return 0;
 550
 551         assert(node);
 552         if (ARR_LEN(node->edges) == 0) return 1;
 553
 554         unsigned bucket_length = ARR_LEN(reduced_bucket);
 555         unsigned bucket_index  = node->bucket_index;
 556
 557         return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;
 558 }