2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
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.
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.
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
22 * @brief Optimal reductions and helper functions.
24 * @author Sebastian Buchwald
29 #include "adt/array.h"
35 #include "html_dumper.h"
40 #include "pbqp_edge.h"
41 #include "pbqp_edge_t.h"
42 #include "pbqp_node.h"
43 #include "pbqp_node_t.h"
49 pbqp_edge_t **edge_bucket;
50 pbqp_edge_t **rm_bucket;
51 pbqp_node_t **node_buckets[4];
52 pbqp_node_t **reduced_bucket = NULL;
53 pbqp_node_t *merged_node = NULL;
54 static int buckets_filled = 0;
56 static void insert_into_edge_bucket(pbqp_edge_t *edge)
58 if (edge_bucket_contains(edge_bucket, edge)) {
59 /* Edge is already inserted. */
63 edge_bucket_insert(&edge_bucket, edge);
66 static void insert_into_rm_bucket(pbqp_edge_t *edge)
68 if (edge_bucket_contains(rm_bucket, edge)) {
69 /* Edge is already inserted. */
73 edge_bucket_insert(&rm_bucket, edge);
76 static void init_buckets(void)
80 edge_bucket_init(&edge_bucket);
81 edge_bucket_init(&rm_bucket);
82 node_bucket_init(&reduced_bucket);
84 for (i = 0; i < 4; ++i) {
85 node_bucket_init(&node_buckets[i]);
89 void free_buckets(void)
93 for (i = 0; i < 4; ++i) {
94 node_bucket_free(&node_buckets[i]);
97 edge_bucket_free(&edge_bucket);
98 edge_bucket_free(&rm_bucket);
99 node_bucket_free(&reduced_bucket);
104 void fill_node_buckets(pbqp_t *pbqp)
110 node_len = pbqp->num_nodes;
113 ir_timer_t *t_fill_buckets = ir_timer_new();
114 ir_timer_start(t_fill_buckets);
117 for (node_index = 0; node_index < node_len; ++node_index) {
119 pbqp_node_t *node = get_node(pbqp, node_index);
123 degree = pbqp_node_get_degree(node);
125 /* We have only one bucket for nodes with arity >= 3. */
130 node_bucket_insert(&node_buckets[degree], node);
136 ir_timer_stop(t_fill_buckets);
137 printf("PBQP Fill Nodes into buckets: %10.3lf msec\n", (double)ir_timer_elapsed_usec(t_fill_buckets) / 1000.0);
141 static void normalize_towards_source(pbqp_edge_t *edge)
144 pbqp_node_t *src_node;
145 pbqp_node_t *tgt_node;
151 unsigned new_infinity = 0;
155 src_node = edge->src;
156 tgt_node = edge->tgt;
160 src_vec = src_node->costs;
161 tgt_vec = tgt_node->costs;
165 src_len = src_vec->len;
166 tgt_len = tgt_vec->len;
173 /* Normalize towards source node. */
174 for (src_index = 0; src_index < src_len; ++src_index) {
175 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
178 if (src_vec->entries[src_index].data == INF_COSTS) {
179 pbqp_matrix_set_row_value(mat, src_index, 0);
183 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
184 src_vec->entries[src_index].data = pbqp_add(
185 src_vec->entries[src_index].data, min);
187 if (min == INF_COSTS) {
195 unsigned edge_len = pbqp_node_get_degree(src_node);
197 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
198 pbqp_edge_t *edge_candidate = src_node->edges[edge_index];
200 if (edge_candidate != edge) {
201 insert_into_edge_bucket(edge_candidate);
207 static void normalize_towards_target(pbqp_edge_t *edge)
210 pbqp_node_t *src_node;
211 pbqp_node_t *tgt_node;
217 unsigned new_infinity = 0;
221 src_node = edge->src;
222 tgt_node = edge->tgt;
226 src_vec = src_node->costs;
227 tgt_vec = tgt_node->costs;
231 src_len = src_vec->len;
232 tgt_len = tgt_vec->len;
239 /* Normalize towards target node. */
240 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
241 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
244 if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
245 pbqp_matrix_set_col_value(mat, tgt_index, 0);
249 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
250 tgt_vec->entries[tgt_index].data = pbqp_add(
251 tgt_vec->entries[tgt_index].data, min);
253 if (min == INF_COSTS) {
261 unsigned edge_len = pbqp_node_get_degree(tgt_node);
263 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
264 pbqp_edge_t *edge_candidate = tgt_node->edges[edge_index];
266 if (edge_candidate != edge) {
267 insert_into_edge_bucket(edge_candidate);
274 * Tries to apply RM for the source node of the given edge.
276 * Checks whether the source node of edge can be merged into the target node of
277 * edge, and performs the merge, if possible.
279 static void merge_source_into_target(pbqp_t *pbqp, pbqp_edge_t *edge)
282 pbqp_node_t *src_node;
283 pbqp_node_t *tgt_node;
297 src_node = edge->src;
298 tgt_node = edge->tgt;
302 src_vec = src_node->costs;
303 tgt_vec = tgt_node->costs;
307 src_len = src_vec->len;
308 tgt_len = tgt_vec->len;
310 /* Matrizes are normalized. */
317 mapping = NEW_ARR_F(unsigned, tgt_len);
319 /* Check that each column has at most one zero entry. */
320 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
321 unsigned onlyOneZero = 0;
323 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
326 for (src_index = 0; src_index < src_len; ++src_index) {
327 if (src_vec->entries[src_index].data == INF_COSTS)
330 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS)
333 /* Matrix entry is finite. */
340 mapping[tgt_index] = src_index;
344 /* We know that we can merge the source node into the target node. */
345 edge_len = pbqp_node_get_degree(src_node);
352 if (pbqp->dump_file) {
354 sprintf(txt, "Merging n%d into n%d", src_node->index, tgt_node->index);
355 dump_section(pbqp->dump_file, 3, txt);
359 /* Reconnect the source's edges with the target node. */
360 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
361 pbqp_edge_t *old_edge = src_node->edges[edge_index];
362 pbqp_edge_t *new_edge;
363 pbqp_matrix_t *old_matrix;
364 pbqp_matrix_t *new_matrix;
365 pbqp_node_t *other_node;
368 unsigned other_index;
373 if (old_edge == edge)
376 old_matrix = old_edge->costs;
379 if (old_edge->tgt == src_node) {
380 other_node = old_edge->src;
381 other_len = old_matrix->rows;
384 other_node = old_edge->tgt;
385 other_len = old_matrix->cols;
388 other_vec = other_node->costs;
390 new_matrix = pbqp_matrix_alloc(pbqp, tgt_len, other_len);
392 /* Source node selects the column of the old_matrix. */
393 if (old_edge->tgt == src_node) {
394 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
395 unsigned src_index = mapping[tgt_index];
397 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
400 for (other_index = 0; other_index < other_len; ++other_index) {
401 if (other_vec->entries[other_index].data == INF_COSTS)
404 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[other_index*src_len+src_index];
408 /* Source node selects the row of the old_matrix. */
410 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
411 unsigned src_index = mapping[tgt_index];
413 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
416 for (other_index = 0; other_index < other_len; ++other_index) {
417 if (other_vec->entries[other_index].data == INF_COSTS)
420 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[src_index*other_len+other_index];
425 new_edge = get_edge(pbqp, tgt_node->index, other_node->index);
427 add_edge_costs(pbqp, tgt_node->index, other_node->index, new_matrix);
429 if (new_edge == NULL) {
430 reorder_node_after_edge_insertion(tgt_node);
431 reorder_node_after_edge_insertion(other_node);
434 delete_edge(old_edge);
436 new_edge = get_edge(pbqp, tgt_node->index, other_node->index);
437 simplify_edge(pbqp, new_edge);
439 insert_into_rm_bucket(new_edge);
448 * Tries to apply RM for the target node of the given edge.
450 * Checks whether the target node of edge can be merged into the source node of
451 * edge, and performs the merge, if possible.
453 static void merge_target_into_source(pbqp_t *pbqp, pbqp_edge_t *edge)
456 pbqp_node_t *src_node;
457 pbqp_node_t *tgt_node;
471 src_node = edge->src;
472 tgt_node = edge->tgt;
476 src_vec = src_node->costs;
477 tgt_vec = tgt_node->costs;
481 src_len = src_vec->len;
482 tgt_len = tgt_vec->len;
484 /* Matrizes are normalized. */
491 mapping = NEW_ARR_F(unsigned, src_len);
493 /* Check that each row has at most one zero entry. */
494 for (src_index = 0; src_index < src_len; ++src_index) {
495 unsigned onlyOneZero = 0;
497 if (src_vec->entries[src_index].data == INF_COSTS)
500 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
501 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
504 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS)
507 /* Matrix entry is finite. */
514 mapping[src_index] = tgt_index;
518 /* We know that we can merge the target node into the source node. */
519 edge_len = pbqp_node_get_degree(tgt_node);
526 if (pbqp->dump_file) {
528 sprintf(txt, "Merging n%d into n%d", tgt_node->index, src_node->index);
529 dump_section(pbqp->dump_file, 3, txt);
533 /* Reconnect the target's edges with the source node. */
534 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
535 pbqp_edge_t *old_edge = tgt_node->edges[edge_index];
536 pbqp_edge_t *new_edge;
537 pbqp_matrix_t *old_matrix;
538 pbqp_matrix_t *new_matrix;
539 pbqp_node_t *other_node;
542 unsigned other_index;
547 if (old_edge == edge)
550 old_matrix = old_edge->costs;
553 if (old_edge->tgt == tgt_node) {
554 other_node = old_edge->src;
555 other_len = old_matrix->rows;
558 other_node = old_edge->tgt;
559 other_len = old_matrix->cols;
562 other_vec = other_node->costs;
564 new_matrix = pbqp_matrix_alloc(pbqp, src_len, other_len);
566 /* Target node selects the column of the old_matrix. */
567 if (old_edge->tgt == tgt_node) {
568 for (src_index = 0; src_index < src_len; ++src_index) {
569 unsigned tgt_index = mapping[src_index];
571 if (src_vec->entries[src_index].data == INF_COSTS)
574 for (other_index = 0; other_index < other_len; ++other_index) {
575 if (other_vec->entries[other_index].data == INF_COSTS)
578 new_matrix->entries[src_index*other_len+other_index] = old_matrix->entries[other_index*tgt_len+tgt_index];
582 /* Source node selects the row of the old_matrix. */
584 for (src_index = 0; src_index < src_len; ++src_index) {
585 unsigned tgt_index = mapping[src_index];
587 if (src_vec->entries[src_index].data == INF_COSTS)
590 for (other_index = 0; other_index < other_len; ++other_index) {
591 if (other_vec->entries[other_index].data == INF_COSTS)
594 new_matrix->entries[src_index*other_len+other_index] = old_matrix->entries[tgt_index*other_len+other_index];
599 new_edge = get_edge(pbqp, src_node->index, other_node->index);
601 add_edge_costs(pbqp, src_node->index, other_node->index, new_matrix);
603 if (new_edge == NULL) {
604 reorder_node_after_edge_insertion(src_node);
605 reorder_node_after_edge_insertion(other_node);
608 delete_edge(old_edge);
610 new_edge = get_edge(pbqp, src_node->index, other_node->index);
611 simplify_edge(pbqp, new_edge);
613 insert_into_rm_bucket(new_edge);
622 * Merge neighbors into the given node.
624 void apply_RM(pbqp_t *pbqp, pbqp_node_t *node)
634 edge_len = pbqp_node_get_degree(node);
636 /* Check all incident edges. */
637 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
638 pbqp_edge_t *edge = edges[edge_index];
640 insert_into_rm_bucket(edge);
643 /* ALAP: Merge neighbors into given node. */
644 while(edge_bucket_get_length(rm_bucket) > 0) {
645 pbqp_edge_t *edge = edge_bucket_pop(&rm_bucket);
648 /* If the edge is not deleted: Try a merge. */
649 if (edge->src == node)
650 merge_target_into_source(pbqp, edge);
651 else if (edge->tgt == node)
652 merge_source_into_target(pbqp, edge);
658 void reorder_node_after_edge_deletion(pbqp_node_t *node)
660 unsigned degree = pbqp_node_get_degree(node);
661 /* Assume node lost one incident edge. */
662 unsigned old_degree = degree + 1;
664 if (!buckets_filled) return;
666 /* Same bucket as before */
667 if (degree > 2) return;
669 /* Delete node from old bucket... */
670 node_bucket_remove(&node_buckets[old_degree], node);
672 /* ..and add to new one. */
673 node_bucket_insert(&node_buckets[degree], node);
676 void reorder_node_after_edge_insertion(pbqp_node_t *node)
678 unsigned degree = pbqp_node_get_degree(node);
679 /* Assume node lost one incident edge. */
680 unsigned old_degree = degree - 1;
682 if (!buckets_filled) return;
684 /* Same bucket as before */
685 if (old_degree > 2) return;
687 /* Delete node from old bucket... */
688 node_bucket_remove(&node_buckets[old_degree], node);
690 /* ..and add to new one. */
691 node_bucket_insert(&node_buckets[degree], node);
694 void simplify_edge(pbqp_t *pbqp, pbqp_edge_t *edge)
697 pbqp_node_t *src_node;
698 pbqp_node_t *tgt_node;
709 src_node = edge->src;
710 tgt_node = edge->tgt;
714 /* If edge are already deleted, we have nothing to do. */
715 if (is_deleted(edge))
719 if (pbqp->dump_file) {
721 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
722 dump_section(pbqp->dump_file, 3, txt);
726 src_vec = src_node->costs;
727 tgt_vec = tgt_node->costs;
731 src_len = src_vec->len;
732 tgt_len = tgt_vec->len;
740 if (pbqp->dump_file) {
741 fputs("Input:<br>\n", pbqp->dump_file);
742 dump_simplifyedge(pbqp, edge);
746 normalize_towards_source(edge);
747 normalize_towards_target(edge);
750 if (pbqp->dump_file) {
751 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
752 dump_simplifyedge(pbqp, edge);
756 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
758 if (pbqp->dump_file) {
759 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
771 void initial_simplify_edges(pbqp_t *pbqp)
779 ir_timer_t *t_int_simpl = ir_timer_new();
780 ir_timer_start(t_int_simpl);
784 if (pbqp->dump_file) {
785 pbqp_dump_input(pbqp);
786 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
790 node_len = pbqp->num_nodes;
794 /* First simplify all edges. */
795 for (node_index = 0; node_index < node_len; ++node_index) {
797 pbqp_node_t *node = get_node(pbqp, node_index);
804 edge_len = pbqp_node_get_degree(node);
806 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
807 pbqp_edge_t *edge = edges[edge_index];
809 /* Simplify only once per edge. */
810 if (node != edge->src) continue;
812 simplify_edge(pbqp, edge);
817 ir_timer_stop(t_int_simpl);
818 printf("PBQP Initial simplify edges: %10.3lf msec\n", (double)ir_timer_elapsed_usec(t_int_simpl) / 1000.0);
822 num determine_solution(pbqp_t *pbqp)
829 ir_timer_t *t_det_solution = ir_timer_new();
830 ir_timer_reset_and_start(t_det_solution);
842 file = pbqp->dump_file;
845 dump_section(file, 1, "4. Determine Solution/Minimum");
846 dump_section(file, 2, "4.1. Trivial Solution");
850 /* Solve trivial nodes and calculate solution. */
851 node_len = node_bucket_get_length(node_buckets[0]);
854 pbqp->num_r0 = node_len;
857 for (node_index = 0; node_index < node_len; ++node_index) {
858 pbqp_node_t *node = node_buckets[0][node_index];
861 node->solution = vector_get_min_index(node->costs);
862 solution = pbqp_add(solution,
863 node->costs->entries[node->solution].data);
867 fprintf(file, "node n%d is set to %d<br>\n", node->index, node->solution);
868 dump_node(file, node);
875 dump_section(file, 2, "Minimum");
876 #if KAPS_USE_UNSIGNED
877 fprintf(file, "Minimum is equal to %u.", solution);
879 fprintf(file, "Minimum is equal to %lld.", solution);
885 ir_timer_stop(t_det_solution);
886 printf("PBQP Determine Solution: %10.3lf msec\n", (double)ir_timer_elapsed_usec(t_det_solution) / 1000.0);
892 static void back_propagate_RI(pbqp_t *pbqp, pbqp_node_t *node)
905 edge = node->edges[0];
907 is_src = edge->src == node;
914 node->solution = pbqp_matrix_get_col_min_index(mat, other->solution, vec);
919 node->solution = pbqp_matrix_get_row_min_index(mat, other->solution, vec);
923 if (pbqp->dump_file) {
924 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
929 static void back_propagate_RII(pbqp_t *pbqp, pbqp_node_t *node)
931 pbqp_edge_t *src_edge = node->edges[0];
932 pbqp_edge_t *tgt_edge = node->edges[1];
933 int src_is_src = src_edge->src == node;
934 int tgt_is_src = tgt_edge->src == node;
935 pbqp_matrix_t *src_mat;
936 pbqp_matrix_t *tgt_mat;
937 pbqp_node_t *src_node;
938 pbqp_node_t *tgt_node;
947 src_node = src_edge->tgt;
949 src_node = src_edge->src;
953 tgt_node = tgt_edge->tgt;
955 tgt_node = tgt_edge->src;
958 /* Swap nodes if necessary. */
959 if (tgt_node->index < src_node->index) {
960 pbqp_node_t *tmp_node;
961 pbqp_edge_t *tmp_edge;
971 src_is_src = src_edge->src == node;
972 tgt_is_src = tgt_edge->src == node;
975 src_mat = src_edge->costs;
976 tgt_mat = tgt_edge->costs;
978 node_vec = node->costs;
980 row_index = src_node->solution;
981 col_index = tgt_node->solution;
983 vec = vector_copy(pbqp, node_vec);
986 vector_add_matrix_col(vec, src_mat, row_index);
988 vector_add_matrix_row(vec, src_mat, row_index);
992 vector_add_matrix_col(vec, tgt_mat, col_index);
994 vector_add_matrix_row(vec, tgt_mat, col_index);
997 node->solution = vector_get_min_index(vec);
1000 if (pbqp->dump_file) {
1001 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
1005 obstack_free(&pbqp->obstack, vec);
1008 void back_propagate(pbqp_t *pbqp)
1010 unsigned node_index;
1011 unsigned node_len = node_bucket_get_length(reduced_bucket);
1016 if (pbqp->dump_file) {
1017 dump_section(pbqp->dump_file, 2, "Back Propagation");
1021 for (node_index = node_len; node_index > 0; --node_index) {
1022 pbqp_node_t *node = reduced_bucket[node_index - 1];
1024 switch (pbqp_node_get_degree(node)) {
1026 back_propagate_RI(pbqp, node);
1029 back_propagate_RII(pbqp, node);
1032 panic("Only nodes with degree one or two should be in this bucket");
1038 void apply_edge(pbqp_t *pbqp)
1040 pbqp_edge_t *edge = edge_bucket_pop(&edge_bucket);
1042 simplify_edge(pbqp, edge);
1045 void apply_RI(pbqp_t *pbqp)
1047 pbqp_node_t *node = node_bucket_pop(&node_buckets[1]);
1048 pbqp_edge_t *edge = node->edges[0];
1049 pbqp_matrix_t *mat = edge->costs;
1050 int is_src = edge->src == node;
1051 pbqp_node_t *other_node;
1054 assert(pbqp_node_get_degree(node) == 1);
1057 other_node = edge->tgt;
1059 other_node = edge->src;
1063 if (pbqp->dump_file) {
1065 sprintf(txt, "RI-Reduction of Node n%d", node->index);
1066 dump_section(pbqp->dump_file, 2, txt);
1067 pbqp_dump_graph(pbqp);
1068 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1069 dump_node(pbqp->dump_file, node);
1070 dump_node(pbqp->dump_file, other_node);
1071 dump_edge(pbqp->dump_file, edge);
1076 pbqp_matrix_add_to_all_cols(mat, node->costs);
1077 normalize_towards_target(edge);
1079 pbqp_matrix_add_to_all_rows(mat, node->costs);
1080 normalize_towards_source(edge);
1082 disconnect_edge(other_node, edge);
1085 if (pbqp->dump_file) {
1086 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1087 dump_node(pbqp->dump_file, other_node);
1091 reorder_node_after_edge_deletion(other_node);
1097 /* Add node to back propagation list. */
1098 node_bucket_insert(&reduced_bucket, node);
1101 void apply_RII(pbqp_t *pbqp)
1103 pbqp_node_t *node = node_bucket_pop(&node_buckets[2]);
1104 pbqp_edge_t *src_edge = node->edges[0];
1105 pbqp_edge_t *tgt_edge = node->edges[1];
1106 int src_is_src = src_edge->src == node;
1107 int tgt_is_src = tgt_edge->src == node;
1108 pbqp_matrix_t *src_mat;
1109 pbqp_matrix_t *tgt_mat;
1110 pbqp_node_t *src_node;
1111 pbqp_node_t *tgt_node;
1124 assert(pbqp_node_get_degree(node) == 2);
1127 src_node = src_edge->tgt;
1129 src_node = src_edge->src;
1133 tgt_node = tgt_edge->tgt;
1135 tgt_node = tgt_edge->src;
1138 /* Swap nodes if necessary. */
1139 if (tgt_node->index < src_node->index) {
1140 pbqp_node_t *tmp_node;
1141 pbqp_edge_t *tmp_edge;
1143 tmp_node = src_node;
1144 src_node = tgt_node;
1145 tgt_node = tmp_node;
1147 tmp_edge = src_edge;
1148 src_edge = tgt_edge;
1149 tgt_edge = tmp_edge;
1151 src_is_src = src_edge->src == node;
1152 tgt_is_src = tgt_edge->src == node;
1156 if (pbqp->dump_file) {
1158 sprintf(txt, "RII-Reduction of Node n%d", node->index);
1159 dump_section(pbqp->dump_file, 2, txt);
1160 pbqp_dump_graph(pbqp);
1161 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1162 dump_node(pbqp->dump_file, src_node);
1163 dump_edge(pbqp->dump_file, src_edge);
1164 dump_node(pbqp->dump_file, node);
1165 dump_edge(pbqp->dump_file, tgt_edge);
1166 dump_node(pbqp->dump_file, tgt_node);
1170 src_mat = src_edge->costs;
1171 tgt_mat = tgt_edge->costs;
1173 src_vec = src_node->costs;
1174 tgt_vec = tgt_node->costs;
1175 node_vec = node->costs;
1177 row_len = src_vec->len;
1178 col_len = tgt_vec->len;
1179 node_len = node_vec->len;
1181 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
1183 for (row_index = 0; row_index < row_len; ++row_index) {
1184 for (col_index = 0; col_index < col_len; ++col_index) {
1185 vec = vector_copy(pbqp, node_vec);
1188 vector_add_matrix_col(vec, src_mat, row_index);
1190 vector_add_matrix_row(vec, src_mat, row_index);
1194 vector_add_matrix_col(vec, tgt_mat, col_index);
1196 vector_add_matrix_row(vec, tgt_mat, col_index);
1199 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
1201 obstack_free(&pbqp->obstack, vec);
1205 pbqp_edge_t *edge = get_edge(pbqp, src_node->index, tgt_node->index);
1207 /* Disconnect node. */
1208 disconnect_edge(src_node, src_edge);
1209 disconnect_edge(tgt_node, tgt_edge);
1215 /* Add node to back propagation list. */
1216 node_bucket_insert(&reduced_bucket, node);
1219 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
1222 pbqp_matrix_add(edge->costs, mat);
1224 /* Free local matrix. */
1225 obstack_free(&pbqp->obstack, mat);
1227 reorder_node_after_edge_deletion(src_node);
1228 reorder_node_after_edge_deletion(tgt_node);
1232 if (pbqp->dump_file) {
1233 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1234 dump_edge(pbqp->dump_file, edge);
1238 /* Edge has changed so we simplify it. */
1239 simplify_edge(pbqp, edge);
1242 static void select_column(pbqp_edge_t *edge, unsigned col_index)
1245 pbqp_node_t *src_node;
1246 pbqp_node_t *tgt_node;
1252 unsigned new_infinity = 0;
1256 src_node = edge->src;
1257 tgt_node = edge->tgt;
1261 src_vec = src_node->costs;
1262 tgt_vec = tgt_node->costs;
1266 src_len = src_vec->len;
1267 tgt_len = tgt_vec->len;
1268 assert(src_len > 0);
1269 assert(tgt_len > 0);
1274 for (src_index = 0; src_index < src_len; ++src_index) {
1275 num elem = mat->entries[src_index * tgt_len + col_index];
1278 if (elem == INF_COSTS && src_vec->entries[src_index].data != INF_COSTS)
1281 src_vec->entries[src_index].data = pbqp_add(
1282 src_vec->entries[src_index].data, elem);
1287 unsigned edge_index;
1288 unsigned edge_len = pbqp_node_get_degree(src_node);
1290 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1291 pbqp_edge_t *edge_candidate = src_node->edges[edge_index];
1293 if (edge_candidate != edge) {
1294 insert_into_edge_bucket(edge_candidate);
1302 static void select_row(pbqp_edge_t *edge, unsigned row_index)
1305 pbqp_node_t *src_node;
1306 pbqp_node_t *tgt_node;
1310 unsigned new_infinity = 0;
1314 src_node = edge->src;
1315 tgt_node = edge->tgt;
1318 tgt_vec = tgt_node->costs;
1321 tgt_len = tgt_vec->len;
1322 assert(tgt_len > 0);
1327 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
1328 num elem = mat->entries[row_index * tgt_len + tgt_index];
1331 if (elem == INF_COSTS && tgt_vec->entries[tgt_index].data != INF_COSTS)
1334 tgt_vec->entries[tgt_index].data = pbqp_add(
1335 tgt_vec->entries[tgt_index].data, elem);
1340 unsigned edge_index;
1341 unsigned edge_len = pbqp_node_get_degree(tgt_node);
1343 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1344 pbqp_edge_t *edge_candidate = tgt_node->edges[edge_index];
1346 if (edge_candidate != edge) {
1347 insert_into_edge_bucket(edge_candidate);
1355 void select_alternative(pbqp_node_t *node, unsigned selected_index)
1357 unsigned edge_index;
1358 unsigned node_index;
1361 unsigned max_degree = pbqp_node_get_degree(node);
1364 node->solution = selected_index;
1365 node_vec = node->costs;
1366 node_len = node_vec->len;
1367 assert(selected_index < node_len);
1369 /* Set all other costs to infinity. */
1370 for (node_index = 0; node_index < node_len; ++node_index) {
1371 if (node_index != selected_index) {
1372 node_vec->entries[node_index].data = INF_COSTS;
1376 /* Select corresponding row/column for incident edges. */
1377 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1378 pbqp_edge_t *edge = node->edges[edge_index];
1380 if (edge->src == node)
1381 select_row(edge, selected_index);
1383 select_column(edge, selected_index);
1387 pbqp_node_t *get_node_with_max_degree(void)
1389 pbqp_node_t **bucket = node_buckets[3];
1390 unsigned bucket_len = node_bucket_get_length(bucket);
1391 unsigned bucket_index;
1392 unsigned max_degree = 0;
1393 pbqp_node_t *result = NULL;
1395 for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
1396 pbqp_node_t *candidate = bucket[bucket_index];
1397 unsigned degree = pbqp_node_get_degree(candidate);
1399 if (degree > max_degree) {
1401 max_degree = degree;
1408 unsigned get_local_minimal_alternative(pbqp_t *pbqp, pbqp_node_t *node)
1414 unsigned edge_index;
1415 unsigned max_degree;
1416 unsigned node_index;
1418 unsigned min_index = 0;
1419 num min = INF_COSTS;
1424 node_vec = node->costs;
1425 node_len = node_vec->len;
1426 max_degree = pbqp_node_get_degree(node);
1428 for (node_index = 0; node_index < node_len; ++node_index) {
1429 num value = node_vec->entries[node_index].data;
1431 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1432 edge = node->edges[edge_index];
1434 is_src = edge->src == node;
1437 vec = vector_copy(pbqp, edge->tgt->costs);
1438 vector_add_matrix_row(vec, mat, node_index);
1440 vec = vector_copy(pbqp, edge->src->costs);
1441 vector_add_matrix_col(vec, mat, node_index);
1444 value = pbqp_add(value, vector_get_min(vec));
1446 obstack_free(&pbqp->obstack, vec);
1451 min_index = node_index;
1458 int node_is_reduced(pbqp_node_t *node)
1460 if (!reduced_bucket) return 0;
1462 if (pbqp_node_get_degree(node) == 0) return 1;
1464 return node_bucket_contains(reduced_bucket, node);