5 #include "heuristical.h"
6 #include "html_dumper.h"
10 #include "pbqp_edge_t.h"
11 #include "pbqp_node.h"
12 #include "pbqp_node_t.h"
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;
20 static void init_buckets(void)
24 edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
25 reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
27 for (i = 0; i < 4; ++i) {
28 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
32 static void free_buckets(void)
36 for (i = 0; i < 4; ++i) {
37 DEL_ARR_F(node_buckets[i]);
40 DEL_ARR_F(edge_bucket);
41 DEL_ARR_F(reduced_bucket);
46 static void fill_node_buckets(pbqp *pbqp)
52 node_len = pbqp->num_nodes;
54 for (node_index = 0; node_index < node_len; ++node_index) {
56 pbqp_node *node = get_node(pbqp, node_index);
60 arity = ARR_LEN(node->edges);
62 /* We have only one bucket for nodes with arity >= 3. */
67 node->bucket_index = ARR_LEN(node_buckets[arity]);
69 ARR_APP1(pbqp_node *, node_buckets[arity], node);
75 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
94 src_vec = src_node->costs;
95 tgt_vec = tgt_node->costs;
99 src_len = src_vec->len;
100 tgt_len = tgt_vec->len;
107 /* Normalize towards source node. */
108 for (src_index = 0; src_index < src_len; ++src_index) {
109 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
112 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
113 src_vec->entries[src_index].data = pbqp_add(
114 src_vec->entries[src_index].data, min);
116 // TODO add to edge_list if inf
121 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
135 src_node = edge->src;
136 tgt_node = edge->tgt;
140 src_vec = src_node->costs;
141 tgt_vec = tgt_node->costs;
145 src_len = src_vec->len;
146 tgt_len = tgt_vec->len;
153 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
154 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
157 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
158 tgt_vec->entries[tgt_index].data = pbqp_add(
159 tgt_vec->entries[tgt_index].data, min);
161 // TODO add to edge_list if inf
166 static void reorder_node(pbqp_node *node)
170 unsigned old_bucket_len;
171 unsigned old_bucket_index;
172 pbqp_node **old_bucket;
175 if (!buckets_filled) return;
179 arity = ARR_LEN(node->edges);
181 /* Same bucket as before */
182 if (arity > 2) return;
184 /* Assume node lost one incident edge. */
185 old_arity = arity + 1;
186 old_bucket = node_buckets[old_arity];
187 old_bucket_len = ARR_LEN(old_bucket);
188 old_bucket_index = node->bucket_index;
190 if (old_bucket_len <= old_bucket_index ||
191 old_bucket[old_bucket_index] != node) {
192 /* Old arity is new arity, so we have nothing to do. */
193 assert(old_bucket_index < ARR_LEN(node_buckets[arity]) &&
194 node_buckets[arity][old_bucket_index] == node);
198 assert(old_bucket[old_bucket_index] == node);
200 /* Delete node from old bucket... */
201 other = old_bucket[old_bucket_len - 1];
202 other->bucket_index = old_bucket_index;
203 old_bucket[old_bucket_index] = other;
204 ARR_SHRINKLEN(node_buckets[old_arity], old_bucket_len - 1);
206 /* ..and add to new one. */
207 node->bucket_index = ARR_LEN(node_buckets[arity]);
208 ARR_APP1(pbqp_node*, node_buckets[arity], node);
211 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
224 src_node = edge->src;
225 tgt_node = edge->tgt;
229 if (pbqp->dump_file) {
231 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
232 dump_section(pbqp->dump_file, 3, txt);
235 src_vec = src_node->costs;
236 tgt_vec = tgt_node->costs;
240 src_len = src_vec->len;
241 tgt_len = tgt_vec->len;
248 if (pbqp->dump_file) {
249 fputs("Input:<br>\n", pbqp->dump_file);
250 dump_simplifyedge(pbqp, edge);
253 normalize_towards_source(pbqp, edge);
254 normalize_towards_target(pbqp, edge);
256 if (pbqp->dump_file) {
257 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
258 dump_simplifyedge(pbqp, edge);
261 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
262 if (pbqp->dump_file) {
263 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
267 reorder_node(src_node);
268 reorder_node(tgt_node);
272 void solve_pbqp_heuristical(pbqp *pbqp)
279 if (pbqp->dump_file) {
280 pbqp_dump_input(pbqp);
281 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
284 node_len = pbqp->num_nodes;
288 /* First simplify all edges. */
289 for (node_index = 0; node_index < node_len; ++node_index) {
291 pbqp_node *node = get_node(pbqp, node_index);
298 edge_len = ARR_LEN(edges);
300 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
301 pbqp_edge *edge = edges[edge_index];
303 /* Simplify only once per edge. */
304 if (node != edge->src) continue;
306 simplify_edge(pbqp, edge);
310 /* Put node into bucket representing their arity. */
311 fill_node_buckets(pbqp);
314 if (ARR_LEN(edge_bucket) > 0) {
315 panic("Please implement edge simplification");
316 } else if (ARR_LEN(node_buckets[1]) > 0) {
318 } else if (ARR_LEN(node_buckets[2]) > 0) {
320 } else if (ARR_LEN(node_buckets[3]) > 0) {
321 panic("Please implement RN simplification");
327 if (pbqp->dump_file) {
328 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
329 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
332 /* Solve trivial nodes and calculate solution. */
333 node_len = ARR_LEN(node_buckets[0]);
334 for (node_index = 0; node_index < node_len; ++node_index) {
335 pbqp_node *node = node_buckets[0][node_index];
338 node->solution = vector_get_min_index(node->costs);
339 pbqp->solution = pbqp_add(pbqp->solution,
340 node->costs->entries[node->solution].data);
341 if (pbqp->dump_file) {
342 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
343 dump_node(pbqp, node);
347 if (pbqp->dump_file) {
348 dump_section(pbqp->dump_file, 2, "Minimum");
349 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
350 dump_section(pbqp->dump_file, 2, "Back Propagation");
353 /* Solve reduced nodes. */
354 node_len = ARR_LEN(reduced_bucket);
355 for (node_index = node_len; node_index > 0; --node_index) {
356 pbqp_node *node = reduced_bucket[node_index - 1];
359 switch (ARR_LEN(node->edges)) {
361 back_propagate_RI(pbqp, node);
364 back_propagate_RII(pbqp, node);
367 panic("Only nodes with degree one or two should be in this bucket");
375 void applyRI(pbqp *pbqp)
377 pbqp_node **bucket = node_buckets[1];
378 unsigned bucket_len = ARR_LEN(bucket);
379 pbqp_node *node = bucket[bucket_len - 1];
380 pbqp_edge *edge = node->edges[0];
381 pbqp_matrix *mat = edge->costs;
382 int is_src = edge->src == node;
383 pbqp_node *other_node;
386 other_node = edge->tgt;
388 other_node = edge->src;
391 if (pbqp->dump_file) {
393 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
394 dump_section(pbqp->dump_file, 2, txt);
395 pbqp_dump_graph(pbqp);
396 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
397 dump_node(pbqp, node);
398 dump_node(pbqp, other_node);
399 dump_edge(pbqp, edge);
403 pbqp_matrix_add_to_all_cols(mat, node->costs);
404 normalize_towards_target(pbqp, edge);
406 pbqp_matrix_add_to_all_rows(mat, node->costs);
407 normalize_towards_source(pbqp, edge);
409 disconnect_edge(other_node, edge);
411 if (pbqp->dump_file) {
412 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
413 dump_node(pbqp, other_node);
416 /* Remove node from bucket... */
417 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
418 reorder_node(other_node);
420 /* ...and add it to back propagation list. */
421 node->bucket_index = ARR_LEN(reduced_bucket);
422 ARR_APP1(pbqp_node *, reduced_bucket, node);
425 void applyRII(pbqp *pbqp)
427 pbqp_node **bucket = node_buckets[2];
428 unsigned bucket_len = ARR_LEN(bucket);
429 pbqp_node *node = bucket[bucket_len - 1];
430 pbqp_edge *src_edge = node->edges[0];
431 pbqp_edge *tgt_edge = node->edges[1];
432 int src_is_src = src_edge->src == node;
433 int tgt_is_src = tgt_edge->src == node;
434 pbqp_matrix *src_mat;
435 pbqp_matrix *tgt_mat;
452 src_node = src_edge->tgt;
454 src_node = src_edge->src;
458 tgt_node = tgt_edge->tgt;
460 tgt_node = tgt_edge->src;
463 /* Swap nodes if necessary. */
464 if (tgt_node->index < src_node->index) {
476 src_is_src = src_edge->src == node;
477 tgt_is_src = tgt_edge->src == node;
480 if (pbqp->dump_file) {
482 sprintf(txt, "RII-Reduktion of Node n%d", node->index);
483 dump_section(pbqp->dump_file, 2, txt);
484 pbqp_dump_graph(pbqp);
485 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
486 dump_node(pbqp, src_node);
487 dump_edge(pbqp, src_edge);
488 dump_node(pbqp, node);
489 dump_edge(pbqp, tgt_edge);
490 dump_node(pbqp, tgt_node);
493 src_mat = src_edge->costs;
494 tgt_mat = tgt_edge->costs;
496 src_vec = src_node->costs;
497 tgt_vec = tgt_node->costs;
498 node_vec = node->costs;
500 row_len = src_vec->len;
501 col_len = tgt_vec->len;
502 node_len = node_vec->len;
504 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
506 for (row_index = 0; row_index < row_len; ++row_index) {
507 for (col_index = 0; col_index < col_len; ++col_index) {
508 vec = vector_copy(pbqp, node_vec);
511 vector_add_matrix_col(vec, src_mat, row_index);
513 vector_add_matrix_row(vec, src_mat, row_index);
517 vector_add_matrix_col(vec, tgt_mat, col_index);
519 vector_add_matrix_row(vec, tgt_mat, col_index);
522 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
524 obstack_free(&pbqp->obstack, vec);
528 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
530 /* Disconnect node. */
531 disconnect_edge(src_node, src_edge);
532 disconnect_edge(tgt_node, tgt_edge);
534 /* Remove node from bucket... */
535 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
537 /* ...and add it to back propagation list. */
538 node->bucket_index = ARR_LEN(reduced_bucket);
539 ARR_APP1(pbqp_node *, reduced_bucket, node);
542 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
544 pbqp_matrix_add(edge->costs, mat);
546 /* Free local matrix. */
547 obstack_free(&pbqp->obstack, mat);
549 reorder_node(src_node);
550 reorder_node(tgt_node);
553 if (pbqp->dump_file) {
554 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
555 dump_edge(pbqp, edge);
558 /* Edge has changed so we simplify it. */
559 simplify_edge(pbqp, edge);
562 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
573 edge = node->edges[0];
575 is_src = edge->src == node;
581 vector_add_matrix_col(vec, mat, other->solution);
585 vector_add_matrix_row(vec, mat, other->solution);
588 node->solution = vector_get_min_index(vec);
589 if (pbqp->dump_file) {
590 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
594 void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
596 pbqp_edge *src_edge = node->edges[0];
597 pbqp_edge *tgt_edge = node->edges[1];
598 int src_is_src = src_edge->src == node;
599 int tgt_is_src = tgt_edge->src == node;
600 pbqp_matrix *src_mat;
601 pbqp_matrix *tgt_mat;
612 src_node = src_edge->tgt;
614 src_node = src_edge->src;
618 tgt_node = tgt_edge->tgt;
620 tgt_node = tgt_edge->src;
623 /* Swap nodes if necessary. */
624 if (tgt_node->index < src_node->index) {
636 src_is_src = src_edge->src == node;
637 tgt_is_src = tgt_edge->src == node;
640 src_mat = src_edge->costs;
641 tgt_mat = tgt_edge->costs;
643 node_vec = node->costs;
645 row_index = src_node->solution;
646 col_index = tgt_node->solution;
648 vec = vector_copy(pbqp, node_vec);
651 vector_add_matrix_col(vec, src_mat, row_index);
653 vector_add_matrix_row(vec, src_mat, row_index);
657 vector_add_matrix_col(vec, tgt_mat, col_index);
659 vector_add_matrix_row(vec, tgt_mat, col_index);
662 node->solution = vector_get_min_index(vec);
663 if (pbqp->dump_file) {
664 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
667 obstack_free(&pbqp->obstack, vec);
670 int node_is_reduced(pbqp_node *node)
672 if (!reduced_bucket) return 0;
675 if (ARR_LEN(node->edges) == 0) return 1;
677 unsigned bucket_length = ARR_LEN(reduced_bucket);
678 unsigned bucket_index = node->bucket_index;
680 return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;