6 #include "heuristical.h"
7 #include "html_dumper.h"
10 #include "pbqp_edge.h"
11 #include "pbqp_edge_t.h"
12 #include "pbqp_node.h"
13 #include "pbqp_node_t.h"
16 static pbqp_edge **edge_bucket;
17 static pbqp_node **node_buckets[4];
18 static pbqp_node **reduced_bucket = NULL;
19 static int buckets_filled = 0;
21 static void insert_into_edge_bucket(pbqp_edge *edge)
23 if (edge_bucket_contains(edge_bucket, edge)) {
24 /* Edge is already inserted. */
28 edge_bucket_insert(&edge_bucket, edge);
31 static void init_buckets(void)
35 edge_bucket_init(&edge_bucket);
36 node_bucket_init(&reduced_bucket);
38 for (i = 0; i < 4; ++i) {
39 node_bucket_init(&node_buckets[i]);
43 static void free_buckets(void)
47 for (i = 0; i < 4; ++i) {
48 node_bucket_free(&node_buckets[i]);
51 edge_bucket_free(&edge_bucket);
52 node_bucket_free(&reduced_bucket);
57 static void fill_node_buckets(pbqp *pbqp)
63 node_len = pbqp->num_nodes;
65 for (node_index = 0; node_index < node_len; ++node_index) {
67 pbqp_node *node = get_node(pbqp, node_index);
71 degree = pbqp_node_get_degree(node);
73 /* We have only one bucket for nodes with arity >= 3. */
78 node_bucket_insert(&node_buckets[degree], node);
84 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
103 src_vec = src_node->costs;
104 tgt_vec = tgt_node->costs;
108 src_len = src_vec->len;
109 tgt_len = tgt_vec->len;
116 /* Normalize towards source node. */
117 for (src_index = 0; src_index < src_len; ++src_index) {
118 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
121 if (src_vec->entries[src_index].data == INF_COSTS) {
122 pbqp_matrix_set_row_value(mat, src_index, 0);
124 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
126 src_vec->entries[src_index].data = pbqp_add(
127 src_vec->entries[src_index].data, min);
129 if (min == INF_COSTS) {
131 unsigned edge_len = pbqp_node_get_degree(src_node);
133 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
134 pbqp_edge *edge_candidate = src_node->edges[edge_index];
135 if (edge_candidate != edge) {
136 insert_into_edge_bucket(edge_candidate);
144 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
158 src_node = edge->src;
159 tgt_node = edge->tgt;
163 src_vec = src_node->costs;
164 tgt_vec = tgt_node->costs;
168 src_len = src_vec->len;
169 tgt_len = tgt_vec->len;
176 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
177 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
180 if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
181 pbqp_matrix_set_col_value(mat, tgt_index, 0);
183 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
185 tgt_vec->entries[tgt_index].data = pbqp_add(
186 tgt_vec->entries[tgt_index].data, min);
188 if (min == INF_COSTS) {
190 unsigned edge_len = pbqp_node_get_degree(tgt_node);
192 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
193 pbqp_edge *edge_candidate = tgt_node->edges[edge_index];
194 if (edge_candidate != edge) {
195 insert_into_edge_bucket(edge_candidate);
203 static void reorder_node(pbqp_node *node)
205 unsigned degree = pbqp_node_get_degree(node);
206 /* Assume node lost one incident edge. */
207 unsigned old_degree = degree + 1;
209 if (!buckets_filled) return;
211 /* Same bucket as before */
212 if (degree > 2) return;
214 if (!node_bucket_contains(node_buckets[old_degree], node)) {
215 /* Old arity is new arity, so we have nothing to do. */
216 assert(node_bucket_contains(node_buckets[degree], node));
220 /* Delete node from old bucket... */
221 node_bucket_remove(&node_buckets[old_degree], node);
223 /* ..and add to new one. */
224 node_bucket_insert(&node_buckets[degree], node);
227 static void check_melting_possibility(pbqp *pbqp, pbqp_edge *edge)
242 src_node = edge->src;
243 tgt_node = edge->tgt;
247 src_vec = src_node->costs;
248 tgt_vec = tgt_node->costs;
252 src_len = src_vec->len;
253 tgt_len = tgt_vec->len;
260 if (src_len == 1 && tgt_len == 1) {
261 //panic("Something is wrong");
265 for (src_index = 0; src_index < src_len; ++src_index) {
267 if (src_vec->entries[src_index].data == INF_COSTS) {
270 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
271 if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
274 if (mat->entries[src_index * tgt_len + tgt_index] == 0) {
283 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS) {
289 allRowsOk &= onlyOneZero;
293 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
295 if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
298 for (src_index = 0; src_index < src_len; ++src_index) {
299 if (src_vec->entries[src_index].data == INF_COSTS) {
302 if (mat->entries[src_index * tgt_len + tgt_index] == 0) {
311 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS) {
317 allColsOk &= onlyOneZero;
320 if (allRowsOk && allColsOk) {
325 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
338 src_node = edge->src;
339 tgt_node = edge->tgt;
343 /* If edge are already deleted, we have nothing to do. */
344 if (!is_connected(src_node, edge) || !is_connected(tgt_node, edge))
347 if (pbqp->dump_file) {
349 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
350 dump_section(pbqp->dump_file, 3, txt);
353 src_vec = src_node->costs;
354 tgt_vec = tgt_node->costs;
358 src_len = src_vec->len;
359 tgt_len = tgt_vec->len;
366 if (pbqp->dump_file) {
367 fputs("Input:<br>\n", pbqp->dump_file);
368 dump_simplifyedge(pbqp, edge);
371 normalize_towards_source(pbqp, edge);
372 normalize_towards_target(pbqp, edge);
374 if (pbqp->dump_file) {
375 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
376 dump_simplifyedge(pbqp, edge);
379 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
380 if (pbqp->dump_file) {
381 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
385 reorder_node(src_node);
386 reorder_node(tgt_node);
388 //check_melting_possibility(pbqp, edge);
392 void solve_pbqp_heuristical(pbqp *pbqp)
399 if (pbqp->dump_file) {
400 pbqp_dump_input(pbqp);
401 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
404 node_len = pbqp->num_nodes;
408 /* First simplify all edges. */
409 for (node_index = 0; node_index < node_len; ++node_index) {
411 pbqp_node *node = get_node(pbqp, node_index);
418 edge_len = pbqp_node_get_degree(node);
420 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
421 pbqp_edge *edge = edges[edge_index];
423 /* Simplify only once per edge. */
424 if (node != edge->src) continue;
426 simplify_edge(pbqp, edge);
430 /* Put node into bucket representing their arity. */
431 fill_node_buckets(pbqp);
434 if (edge_bucket_get_length(edge_bucket) > 0) {
436 } else if (node_bucket_get_length(node_buckets[1]) > 0) {
438 } else if (node_bucket_get_length(node_buckets[2]) > 0) {
440 } else if (node_bucket_get_length(node_buckets[3]) > 0) {
447 if (pbqp->dump_file) {
448 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
449 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
452 /* Solve trivial nodes and calculate solution. */
453 node_len = node_bucket_get_length(node_buckets[0]);
454 for (node_index = 0; node_index < node_len; ++node_index) {
455 pbqp_node *node = node_buckets[0][node_index];
458 node->solution = vector_get_min_index(node->costs);
459 pbqp->solution = pbqp_add(pbqp->solution,
460 node->costs->entries[node->solution].data);
461 if (pbqp->dump_file) {
462 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
463 dump_node(pbqp, node);
467 if (pbqp->dump_file) {
468 dump_section(pbqp->dump_file, 2, "Minimum");
469 fprintf(pbqp->dump_file, "Minimum is equal to %lld.", pbqp->solution);
470 dump_section(pbqp->dump_file, 2, "Back Propagation");
473 /* Solve reduced nodes. */
474 node_len = node_bucket_get_length(reduced_bucket);
475 for (node_index = node_len; node_index > 0; --node_index) {
476 pbqp_node *node = reduced_bucket[node_index - 1];
478 switch (pbqp_node_get_degree(node)) {
480 back_propagate_RI(pbqp, node);
483 back_propagate_RII(pbqp, node);
486 panic("Only nodes with degree one or two should be in this bucket");
494 void apply_edge(pbqp *pbqp)
496 pbqp_edge *edge = edge_bucket_pop(&edge_bucket);
498 simplify_edge(pbqp, edge);
501 void apply_RI(pbqp *pbqp)
503 pbqp_node *node = node_bucket_pop(&node_buckets[1]);
504 pbqp_edge *edge = node->edges[0];
505 pbqp_matrix *mat = edge->costs;
506 int is_src = edge->src == node;
507 pbqp_node *other_node;
510 other_node = edge->tgt;
512 other_node = edge->src;
515 if (pbqp->dump_file) {
517 sprintf(txt, "RI-Reduction of Node n%d", node->index);
518 dump_section(pbqp->dump_file, 2, txt);
519 pbqp_dump_graph(pbqp);
520 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
521 dump_node(pbqp, node);
522 dump_node(pbqp, other_node);
523 dump_edge(pbqp, edge);
527 pbqp_matrix_add_to_all_cols(mat, node->costs);
528 normalize_towards_target(pbqp, edge);
530 pbqp_matrix_add_to_all_rows(mat, node->costs);
531 normalize_towards_source(pbqp, edge);
533 disconnect_edge(other_node, edge);
535 if (pbqp->dump_file) {
536 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
537 dump_node(pbqp, other_node);
540 reorder_node(other_node);
542 /* Add node to back propagation list. */
543 node_bucket_insert(&reduced_bucket, node);
546 void apply_RII(pbqp *pbqp)
548 pbqp_node *node = node_bucket_pop(&node_buckets[2]);
549 pbqp_edge *src_edge = node->edges[0];
550 pbqp_edge *tgt_edge = node->edges[1];
551 int src_is_src = src_edge->src == node;
552 int tgt_is_src = tgt_edge->src == node;
553 pbqp_matrix *src_mat;
554 pbqp_matrix *tgt_mat;
571 src_node = src_edge->tgt;
573 src_node = src_edge->src;
577 tgt_node = tgt_edge->tgt;
579 tgt_node = tgt_edge->src;
582 /* Swap nodes if necessary. */
583 if (tgt_node->index < src_node->index) {
595 src_is_src = src_edge->src == node;
596 tgt_is_src = tgt_edge->src == node;
599 if (pbqp->dump_file) {
601 sprintf(txt, "RII-Reduction of Node n%d", node->index);
602 dump_section(pbqp->dump_file, 2, txt);
603 pbqp_dump_graph(pbqp);
604 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
605 dump_node(pbqp, src_node);
606 dump_edge(pbqp, src_edge);
607 dump_node(pbqp, node);
608 dump_edge(pbqp, tgt_edge);
609 dump_node(pbqp, tgt_node);
612 src_mat = src_edge->costs;
613 tgt_mat = tgt_edge->costs;
615 src_vec = src_node->costs;
616 tgt_vec = tgt_node->costs;
617 node_vec = node->costs;
619 row_len = src_vec->len;
620 col_len = tgt_vec->len;
621 node_len = node_vec->len;
623 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
625 for (row_index = 0; row_index < row_len; ++row_index) {
626 for (col_index = 0; col_index < col_len; ++col_index) {
627 vec = vector_copy(pbqp, node_vec);
630 vector_add_matrix_col(vec, src_mat, row_index);
632 vector_add_matrix_row(vec, src_mat, row_index);
636 vector_add_matrix_col(vec, tgt_mat, col_index);
638 vector_add_matrix_row(vec, tgt_mat, col_index);
641 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
643 obstack_free(&pbqp->obstack, vec);
647 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
649 /* Disconnect node. */
650 disconnect_edge(src_node, src_edge);
651 disconnect_edge(tgt_node, tgt_edge);
653 /* Add node to back propagation list. */
654 node_bucket_insert(&reduced_bucket, node);
657 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
659 pbqp_matrix_add(edge->costs, mat);
661 /* Free local matrix. */
662 obstack_free(&pbqp->obstack, mat);
664 reorder_node(src_node);
665 reorder_node(tgt_node);
668 if (pbqp->dump_file) {
669 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
670 dump_edge(pbqp, edge);
673 /* Edge has changed so we simplify it. */
674 simplify_edge(pbqp, edge);
677 void apply_RN(pbqp *pbqp)
679 pbqp_node **bucket = node_buckets[3];
680 unsigned bucket_len = node_bucket_get_length(bucket);
681 unsigned bucket_index;
682 pbqp_node *node = NULL;
688 unsigned max_degree = 0;
691 unsigned min_index = 0;
697 /* Search for node with maximum degree. */
698 for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
699 pbqp_node *candidate = bucket[bucket_index];
700 unsigned degree = pbqp_node_get_degree(candidate);
702 if (degree > max_degree) {
708 node_vec = node->costs;
709 node_len = node_vec->len;
711 if (pbqp->dump_file) {
713 sprintf(txt, "RN-Reduction of Node n%d", node->index);
714 dump_section(pbqp->dump_file, 2, txt);
715 pbqp_dump_graph(pbqp);
718 for (node_index = 0; node_index < node_len; ++node_index) {
719 num value = node_vec->entries[node_index].data;
721 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
722 edge = node->edges[edge_index];
724 is_src = edge->src == node;
727 vec = vector_copy(pbqp, edge->tgt->costs);
728 vector_add_matrix_row(vec, mat, node_index);
730 vec = vector_copy(pbqp, edge->src->costs);
731 vector_add_matrix_col(vec, mat, node_index);
734 value = pbqp_add(value, vector_get_min(vec));
736 obstack_free(&pbqp->obstack, vec);
741 min_index = node_index;
745 if (pbqp->dump_file) {
746 fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
747 node->index, min_index);
748 fprintf(pbqp->dump_file, "Minimal cost of RN reduction: %lld<br>\n",
752 node->solution = min_index;
754 /* Now that we found the local minimum set all other costs to infinity. */
755 for (node_index = 0; node_index < node_len; ++node_index) {
756 if (node_index != min_index) {
757 node_vec->entries[node_index].data = INF_COSTS;
761 /* Add all incident edges to edge bucket, since they are now independent. */
762 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
763 insert_into_edge_bucket(node->edges[edge_index]);
767 void apply_Brute_Force(pbqp *pbqp)
769 pbqp_node **bucket = node_buckets[3];
770 unsigned bucket_len = node_bucket_get_length(bucket);
771 unsigned bucket_index;
772 pbqp_node *node = NULL;
778 unsigned max_degree = 0;
781 unsigned min_index = 0;
787 /* Search for node with maximum degree. */
788 for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
789 pbqp_node *candidate = bucket[bucket_index];
790 unsigned degree = pbqp_node_get_degree(candidate);
792 if (degree > max_degree) {
798 node_vec = node->costs;
799 node_len = node_vec->len;
801 if (pbqp->dump_file) {
803 sprintf(txt, "RN-Reduction of Node n%d", node->index);
804 dump_section(pbqp->dump_file, 2, txt);
805 pbqp_dump_graph(pbqp);
808 for (node_index = 0; node_index < node_len; ++node_index) {
809 num value = node_vec->entries[node_index].data;
816 min_index = node_index;
820 if (pbqp->dump_file) {
821 fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
822 node->index, min_index);
823 fprintf(pbqp->dump_file, "Minimal cost of RN reduction: %lld<br>\n",
827 node->solution = min_index;
829 /* Now that we found the local minimum set all other costs to infinity. */
830 for (node_index = 0; node_index < node_len; ++node_index) {
831 if (node_index != min_index) {
832 node_vec->entries[node_index].data = INF_COSTS;
836 /* Add all incident edges to edge bucket, since they are now independent. */
837 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
838 insert_into_edge_bucket(node->edges[edge_index]);
842 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
853 edge = node->edges[0];
855 is_src = edge->src == node;
861 vector_add_matrix_col(vec, mat, other->solution);
865 vector_add_matrix_row(vec, mat, other->solution);
868 node->solution = vector_get_min_index(vec);
869 if (pbqp->dump_file) {
870 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
874 void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
876 pbqp_edge *src_edge = node->edges[0];
877 pbqp_edge *tgt_edge = node->edges[1];
878 int src_is_src = src_edge->src == node;
879 int tgt_is_src = tgt_edge->src == node;
880 pbqp_matrix *src_mat;
881 pbqp_matrix *tgt_mat;
892 src_node = src_edge->tgt;
894 src_node = src_edge->src;
898 tgt_node = tgt_edge->tgt;
900 tgt_node = tgt_edge->src;
903 /* Swap nodes if necessary. */
904 if (tgt_node->index < src_node->index) {
916 src_is_src = src_edge->src == node;
917 tgt_is_src = tgt_edge->src == node;
920 src_mat = src_edge->costs;
921 tgt_mat = tgt_edge->costs;
923 node_vec = node->costs;
925 row_index = src_node->solution;
926 col_index = tgt_node->solution;
928 vec = vector_copy(pbqp, node_vec);
931 vector_add_matrix_col(vec, src_mat, row_index);
933 vector_add_matrix_row(vec, src_mat, row_index);
937 vector_add_matrix_col(vec, tgt_mat, col_index);
939 vector_add_matrix_row(vec, tgt_mat, col_index);
942 node->solution = vector_get_min_index(vec);
943 if (pbqp->dump_file) {
944 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
947 obstack_free(&pbqp->obstack, vec);
950 int node_is_reduced(pbqp_node *node)
952 if (!reduced_bucket) return 0;
954 if (pbqp_node_get_degree(node) == 0) return 1;
956 return node_bucket_contains(reduced_bucket, node);