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 **edge_bucket;
50 pbqp_edge **rm_bucket;
51 pbqp_node **node_buckets[4];
52 pbqp_node **reduced_bucket = NULL;
53 pbqp_node *merged_node = NULL;
54 static int buckets_filled = 0;
56 static void insert_into_edge_bucket(pbqp_edge *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 *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 *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 *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 *edge)
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 *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 *edge)
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 *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 *pbqp, pbqp_edge *edge)
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);
351 /* Reconnect the source's edges with the target node. */
352 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
353 pbqp_edge *old_edge = src_node->edges[edge_index];
355 pbqp_matrix *old_matrix;
356 pbqp_matrix *new_matrix;
357 pbqp_node *other_node;
360 unsigned other_index;
365 if (old_edge == edge)
368 old_matrix = old_edge->costs;
371 if (old_edge->tgt == src_node) {
372 other_node = old_edge->src;
373 other_len = old_matrix->rows;
376 other_node = old_edge->tgt;
377 other_len = old_matrix->cols;
380 other_vec = other_node->costs;
382 new_matrix = pbqp_matrix_alloc(pbqp, tgt_len, other_len);
384 /* Source node selects the column of the old_matrix. */
385 if (old_edge->tgt == src_node) {
386 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
387 unsigned src_index = mapping[tgt_index];
389 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
392 for (other_index = 0; other_index < other_len; ++other_index) {
393 if (other_vec->entries[other_index].data == INF_COSTS)
396 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[other_index*src_len+src_index];
400 /* Source node selects the row of the old_matrix. */
402 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
403 unsigned src_index = mapping[tgt_index];
405 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
408 for (other_index = 0; other_index < other_len; ++other_index) {
409 if (other_vec->entries[other_index].data == INF_COSTS)
412 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[src_index*other_len+other_index];
417 new_edge = get_edge(pbqp, tgt_node->index, other_node->index);
419 add_edge_costs(pbqp, tgt_node->index, other_node->index, new_matrix);
421 if (new_edge == NULL) {
422 reorder_node_after_edge_insertion(tgt_node);
423 reorder_node_after_edge_insertion(other_node);
426 delete_edge(old_edge);
428 new_edge = get_edge(pbqp, tgt_node->index, other_node->index);
429 simplify_edge(pbqp, new_edge);
431 insert_into_rm_bucket(new_edge);
440 * Tries to apply RM for the target node of the given edge.
442 * Checks whether the target node of edge can be merged into the source node of
443 * edge, and performs the merge, if possible.
445 static void merge_target_into_source(pbqp *pbqp, pbqp_edge *edge)
463 src_node = edge->src;
464 tgt_node = edge->tgt;
468 src_vec = src_node->costs;
469 tgt_vec = tgt_node->costs;
473 src_len = src_vec->len;
474 tgt_len = tgt_vec->len;
476 /* Matrizes are normalized. */
483 mapping = NEW_ARR_F(unsigned, src_len);
485 /* Check that each row has at most one zero entry. */
486 for (src_index = 0; src_index < src_len; ++src_index) {
487 unsigned onlyOneZero = 0;
489 if (src_vec->entries[src_index].data == INF_COSTS)
492 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
493 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
496 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS)
499 /* Matrix entry is finite. */
506 mapping[src_index] = tgt_index;
510 /* We know that we can merge the target node into the source node. */
511 edge_len = pbqp_node_get_degree(tgt_node);
517 /* Reconnect the target's edges with the source node. */
518 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
519 pbqp_edge *old_edge = tgt_node->edges[edge_index];
521 pbqp_matrix *old_matrix;
522 pbqp_matrix *new_matrix;
523 pbqp_node *other_node;
526 unsigned other_index;
531 if (old_edge == edge)
534 old_matrix = old_edge->costs;
537 if (old_edge->tgt == tgt_node) {
538 other_node = old_edge->src;
539 other_len = old_matrix->rows;
542 other_node = old_edge->tgt;
543 other_len = old_matrix->cols;
546 other_vec = other_node->costs;
548 new_matrix = pbqp_matrix_alloc(pbqp, src_len, other_len);
550 /* Target node selects the column of the old_matrix. */
551 if (old_edge->tgt == tgt_node) {
552 for (src_index = 0; src_index < src_len; ++src_index) {
553 unsigned tgt_index = mapping[src_index];
555 if (src_vec->entries[src_index].data == INF_COSTS)
558 for (other_index = 0; other_index < other_len; ++other_index) {
559 if (other_vec->entries[other_index].data == INF_COSTS)
562 new_matrix->entries[src_index*other_len+other_index] = old_matrix->entries[other_index*tgt_len+tgt_index];
566 /* Source node selects the row of the old_matrix. */
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[tgt_index*other_len+other_index];
583 new_edge = get_edge(pbqp, src_node->index, other_node->index);
585 add_edge_costs(pbqp, src_node->index, other_node->index, new_matrix);
587 if (new_edge == NULL) {
588 reorder_node_after_edge_insertion(src_node);
589 reorder_node_after_edge_insertion(other_node);
592 delete_edge(old_edge);
594 new_edge = get_edge(pbqp, src_node->index, other_node->index);
595 simplify_edge(pbqp, new_edge);
597 insert_into_rm_bucket(new_edge);
606 * Merge neighbors into the given node.
608 void apply_RM(pbqp *pbqp, pbqp_node *node)
618 edge_len = pbqp_node_get_degree(node);
620 /* Check all incident edges. */
621 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
622 pbqp_edge *edge = edges[edge_index];
624 insert_into_rm_bucket(edge);
627 /* ALAP: Merge neighbors into given node. */
628 while(edge_bucket_get_length(rm_bucket) > 0) {
629 pbqp_edge *edge = edge_bucket_pop(&rm_bucket);
632 /* If the edge is not deleted: Try a merge. */
633 if (edge->src == node)
634 merge_target_into_source(pbqp, edge);
635 else if (edge->tgt == node)
636 merge_source_into_target(pbqp, edge);
642 void reorder_node_after_edge_deletion(pbqp_node *node)
644 unsigned degree = pbqp_node_get_degree(node);
645 /* Assume node lost one incident edge. */
646 unsigned old_degree = degree + 1;
648 if (!buckets_filled) return;
650 /* Same bucket as before */
651 if (degree > 2) return;
653 /* Delete node from old bucket... */
654 node_bucket_remove(&node_buckets[old_degree], node);
656 /* ..and add to new one. */
657 node_bucket_insert(&node_buckets[degree], node);
660 void reorder_node_after_edge_insertion(pbqp_node *node)
662 unsigned degree = pbqp_node_get_degree(node);
663 /* Assume node lost one incident edge. */
664 unsigned old_degree = degree - 1;
666 if (!buckets_filled) return;
668 /* Same bucket as before */
669 if (old_degree > 2) return;
671 /* Delete node from old bucket... */
672 node_bucket_remove(&node_buckets[old_degree], node);
674 /* ..and add to new one. */
675 node_bucket_insert(&node_buckets[degree], node);
678 void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
693 src_node = edge->src;
694 tgt_node = edge->tgt;
698 /* If edge are already deleted, we have nothing to do. */
699 if (is_deleted(edge))
703 if (pbqp->dump_file) {
705 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
706 dump_section(pbqp->dump_file, 3, txt);
710 src_vec = src_node->costs;
711 tgt_vec = tgt_node->costs;
715 src_len = src_vec->len;
716 tgt_len = tgt_vec->len;
724 if (pbqp->dump_file) {
725 fputs("Input:<br>\n", pbqp->dump_file);
726 dump_simplifyedge(pbqp, edge);
730 normalize_towards_source(edge);
731 normalize_towards_target(edge);
734 if (pbqp->dump_file) {
735 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
736 dump_simplifyedge(pbqp, edge);
740 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
742 if (pbqp->dump_file) {
743 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
755 void initial_simplify_edges(pbqp *pbqp)
763 ir_timer_t *t_int_simpl = ir_timer_new();
764 ir_timer_start(t_int_simpl);
768 if (pbqp->dump_file) {
769 pbqp_dump_input(pbqp);
770 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
774 node_len = pbqp->num_nodes;
778 /* First simplify all edges. */
779 for (node_index = 0; node_index < node_len; ++node_index) {
781 pbqp_node *node = get_node(pbqp, node_index);
788 edge_len = pbqp_node_get_degree(node);
790 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
791 pbqp_edge *edge = edges[edge_index];
793 /* Simplify only once per edge. */
794 if (node != edge->src) continue;
796 simplify_edge(pbqp, edge);
801 ir_timer_stop(t_int_simpl);
802 printf("PBQP Initial simplify edges: %10.3lf msec\n", (double)ir_timer_elapsed_usec(t_int_simpl) / 1000.0);
806 num determine_solution(pbqp *pbqp)
813 ir_timer_t *t_det_solution = ir_timer_new();
814 ir_timer_reset_and_start(t_det_solution);
826 file = pbqp->dump_file;
829 dump_section(file, 1, "4. Determine Solution/Minimum");
830 dump_section(file, 2, "4.1. Trivial Solution");
834 /* Solve trivial nodes and calculate solution. */
835 node_len = node_bucket_get_length(node_buckets[0]);
838 pbqp->num_r0 = node_len;
841 for (node_index = 0; node_index < node_len; ++node_index) {
842 pbqp_node *node = node_buckets[0][node_index];
845 node->solution = vector_get_min_index(node->costs);
846 solution = pbqp_add(solution,
847 node->costs->entries[node->solution].data);
851 fprintf(file, "node n%d is set to %d<br>\n", node->index, node->solution);
852 dump_node(file, node);
859 dump_section(file, 2, "Minimum");
860 #if KAPS_USE_UNSIGNED
861 fprintf(file, "Minimum is equal to %u.", solution);
863 fprintf(file, "Minimum is equal to %lld.", solution);
869 ir_timer_stop(t_det_solution);
870 printf("PBQP Determine Solution: %10.3lf msec\n", (double)ir_timer_elapsed_usec(t_det_solution) / 1000.0);
876 static void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
889 edge = node->edges[0];
891 is_src = edge->src == node;
898 node->solution = pbqp_matrix_get_col_min_index(mat, other->solution, vec);
903 node->solution = pbqp_matrix_get_row_min_index(mat, other->solution, vec);
907 if (pbqp->dump_file) {
908 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
913 static void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
915 pbqp_edge *src_edge = node->edges[0];
916 pbqp_edge *tgt_edge = node->edges[1];
917 int src_is_src = src_edge->src == node;
918 int tgt_is_src = tgt_edge->src == node;
919 pbqp_matrix *src_mat;
920 pbqp_matrix *tgt_mat;
931 src_node = src_edge->tgt;
933 src_node = src_edge->src;
937 tgt_node = tgt_edge->tgt;
939 tgt_node = tgt_edge->src;
942 /* Swap nodes if necessary. */
943 if (tgt_node->index < src_node->index) {
955 src_is_src = src_edge->src == node;
956 tgt_is_src = tgt_edge->src == node;
959 src_mat = src_edge->costs;
960 tgt_mat = tgt_edge->costs;
962 node_vec = node->costs;
964 row_index = src_node->solution;
965 col_index = tgt_node->solution;
967 vec = vector_copy(pbqp, node_vec);
970 vector_add_matrix_col(vec, src_mat, row_index);
972 vector_add_matrix_row(vec, src_mat, row_index);
976 vector_add_matrix_col(vec, tgt_mat, col_index);
978 vector_add_matrix_row(vec, tgt_mat, col_index);
981 node->solution = vector_get_min_index(vec);
984 if (pbqp->dump_file) {
985 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
989 obstack_free(&pbqp->obstack, vec);
992 void back_propagate(pbqp *pbqp)
995 unsigned node_len = node_bucket_get_length(reduced_bucket);
1000 if (pbqp->dump_file) {
1001 dump_section(pbqp->dump_file, 2, "Back Propagation");
1005 for (node_index = node_len; node_index > 0; --node_index) {
1006 pbqp_node *node = reduced_bucket[node_index - 1];
1008 switch (pbqp_node_get_degree(node)) {
1010 back_propagate_RI(pbqp, node);
1013 back_propagate_RII(pbqp, node);
1016 panic("Only nodes with degree one or two should be in this bucket");
1022 void apply_edge(pbqp *pbqp)
1024 pbqp_edge *edge = edge_bucket_pop(&edge_bucket);
1026 simplify_edge(pbqp, edge);
1029 void apply_RI(pbqp *pbqp)
1031 pbqp_node *node = node_bucket_pop(&node_buckets[1]);
1032 pbqp_edge *edge = node->edges[0];
1033 pbqp_matrix *mat = edge->costs;
1034 int is_src = edge->src == node;
1035 pbqp_node *other_node;
1038 assert(pbqp_node_get_degree(node) == 1);
1041 other_node = edge->tgt;
1043 other_node = edge->src;
1047 if (pbqp->dump_file) {
1049 sprintf(txt, "RI-Reduction of Node n%d", node->index);
1050 dump_section(pbqp->dump_file, 2, txt);
1051 pbqp_dump_graph(pbqp);
1052 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1053 dump_node(pbqp->dump_file, node);
1054 dump_node(pbqp->dump_file, other_node);
1055 dump_edge(pbqp->dump_file, edge);
1060 pbqp_matrix_add_to_all_cols(mat, node->costs);
1061 normalize_towards_target(edge);
1063 pbqp_matrix_add_to_all_rows(mat, node->costs);
1064 normalize_towards_source(edge);
1066 disconnect_edge(other_node, edge);
1069 if (pbqp->dump_file) {
1070 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1071 dump_node(pbqp->dump_file, other_node);
1075 reorder_node_after_edge_deletion(other_node);
1081 /* Add node to back propagation list. */
1082 node_bucket_insert(&reduced_bucket, node);
1085 void apply_RII(pbqp *pbqp)
1087 pbqp_node *node = node_bucket_pop(&node_buckets[2]);
1088 pbqp_edge *src_edge = node->edges[0];
1089 pbqp_edge *tgt_edge = node->edges[1];
1090 int src_is_src = src_edge->src == node;
1091 int tgt_is_src = tgt_edge->src == node;
1092 pbqp_matrix *src_mat;
1093 pbqp_matrix *tgt_mat;
1094 pbqp_node *src_node;
1095 pbqp_node *tgt_node;
1108 assert(pbqp_node_get_degree(node) == 2);
1111 src_node = src_edge->tgt;
1113 src_node = src_edge->src;
1117 tgt_node = tgt_edge->tgt;
1119 tgt_node = tgt_edge->src;
1122 /* Swap nodes if necessary. */
1123 if (tgt_node->index < src_node->index) {
1124 pbqp_node *tmp_node;
1125 pbqp_edge *tmp_edge;
1127 tmp_node = src_node;
1128 src_node = tgt_node;
1129 tgt_node = tmp_node;
1131 tmp_edge = src_edge;
1132 src_edge = tgt_edge;
1133 tgt_edge = tmp_edge;
1135 src_is_src = src_edge->src == node;
1136 tgt_is_src = tgt_edge->src == node;
1140 if (pbqp->dump_file) {
1142 sprintf(txt, "RII-Reduction of Node n%d", node->index);
1143 dump_section(pbqp->dump_file, 2, txt);
1144 pbqp_dump_graph(pbqp);
1145 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1146 dump_node(pbqp->dump_file, src_node);
1147 dump_edge(pbqp->dump_file, src_edge);
1148 dump_node(pbqp->dump_file, node);
1149 dump_edge(pbqp->dump_file, tgt_edge);
1150 dump_node(pbqp->dump_file, tgt_node);
1154 src_mat = src_edge->costs;
1155 tgt_mat = tgt_edge->costs;
1157 src_vec = src_node->costs;
1158 tgt_vec = tgt_node->costs;
1159 node_vec = node->costs;
1161 row_len = src_vec->len;
1162 col_len = tgt_vec->len;
1163 node_len = node_vec->len;
1165 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
1167 for (row_index = 0; row_index < row_len; ++row_index) {
1168 for (col_index = 0; col_index < col_len; ++col_index) {
1169 vec = vector_copy(pbqp, node_vec);
1172 vector_add_matrix_col(vec, src_mat, row_index);
1174 vector_add_matrix_row(vec, src_mat, row_index);
1178 vector_add_matrix_col(vec, tgt_mat, col_index);
1180 vector_add_matrix_row(vec, tgt_mat, col_index);
1183 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
1185 obstack_free(&pbqp->obstack, vec);
1189 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
1191 /* Disconnect node. */
1192 disconnect_edge(src_node, src_edge);
1193 disconnect_edge(tgt_node, tgt_edge);
1199 /* Add node to back propagation list. */
1200 node_bucket_insert(&reduced_bucket, node);
1203 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
1206 pbqp_matrix_add(edge->costs, mat);
1208 /* Free local matrix. */
1209 obstack_free(&pbqp->obstack, mat);
1211 reorder_node_after_edge_deletion(src_node);
1212 reorder_node_after_edge_deletion(tgt_node);
1216 if (pbqp->dump_file) {
1217 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1218 dump_edge(pbqp->dump_file, edge);
1222 /* Edge has changed so we simplify it. */
1223 simplify_edge(pbqp, edge);
1226 static void select_column(pbqp_edge *edge, unsigned col_index)
1229 pbqp_node *src_node;
1230 pbqp_node *tgt_node;
1236 unsigned new_infinity = 0;
1240 src_node = edge->src;
1241 tgt_node = edge->tgt;
1245 src_vec = src_node->costs;
1246 tgt_vec = tgt_node->costs;
1250 src_len = src_vec->len;
1251 tgt_len = tgt_vec->len;
1252 assert(src_len > 0);
1253 assert(tgt_len > 0);
1258 for (src_index = 0; src_index < src_len; ++src_index) {
1259 num elem = mat->entries[src_index * tgt_len + col_index];
1262 if (elem == INF_COSTS && src_vec->entries[src_index].data != INF_COSTS)
1265 src_vec->entries[src_index].data = pbqp_add(
1266 src_vec->entries[src_index].data, elem);
1271 unsigned edge_index;
1272 unsigned edge_len = pbqp_node_get_degree(src_node);
1274 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1275 pbqp_edge *edge_candidate = src_node->edges[edge_index];
1277 if (edge_candidate != edge) {
1278 insert_into_edge_bucket(edge_candidate);
1286 static void select_row(pbqp_edge *edge, unsigned row_index)
1289 pbqp_node *src_node;
1290 pbqp_node *tgt_node;
1294 unsigned new_infinity = 0;
1298 src_node = edge->src;
1299 tgt_node = edge->tgt;
1302 tgt_vec = tgt_node->costs;
1305 tgt_len = tgt_vec->len;
1306 assert(tgt_len > 0);
1311 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
1312 num elem = mat->entries[row_index * tgt_len + tgt_index];
1315 if (elem == INF_COSTS && tgt_vec->entries[tgt_index].data != INF_COSTS)
1318 tgt_vec->entries[tgt_index].data = pbqp_add(
1319 tgt_vec->entries[tgt_index].data, elem);
1324 unsigned edge_index;
1325 unsigned edge_len = pbqp_node_get_degree(tgt_node);
1327 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1328 pbqp_edge *edge_candidate = tgt_node->edges[edge_index];
1330 if (edge_candidate != edge) {
1331 insert_into_edge_bucket(edge_candidate);
1339 void select_alternative(pbqp_node *node, unsigned selected_index)
1341 unsigned edge_index;
1342 unsigned node_index;
1345 unsigned max_degree = pbqp_node_get_degree(node);
1348 node->solution = selected_index;
1349 node_vec = node->costs;
1350 node_len = node_vec->len;
1351 assert(selected_index < node_len);
1353 /* Set all other costs to infinity. */
1354 for (node_index = 0; node_index < node_len; ++node_index) {
1355 if (node_index != selected_index) {
1356 node_vec->entries[node_index].data = INF_COSTS;
1360 /* Select corresponding row/column for incident edges. */
1361 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1362 pbqp_edge *edge = node->edges[edge_index];
1364 if (edge->src == node)
1365 select_row(edge, selected_index);
1367 select_column(edge, selected_index);
1371 pbqp_node *get_node_with_max_degree(void)
1373 pbqp_node **bucket = node_buckets[3];
1374 unsigned bucket_len = node_bucket_get_length(bucket);
1375 unsigned bucket_index;
1376 unsigned max_degree = 0;
1377 pbqp_node *result = NULL;
1379 for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
1380 pbqp_node *candidate = bucket[bucket_index];
1381 unsigned degree = pbqp_node_get_degree(candidate);
1383 if (degree > max_degree) {
1385 max_degree = degree;
1392 unsigned get_local_minimal_alternative(pbqp *pbqp, pbqp_node *node)
1398 unsigned edge_index;
1399 unsigned max_degree;
1400 unsigned node_index;
1402 unsigned min_index = 0;
1403 num min = INF_COSTS;
1408 node_vec = node->costs;
1409 node_len = node_vec->len;
1410 max_degree = pbqp_node_get_degree(node);
1412 for (node_index = 0; node_index < node_len; ++node_index) {
1413 num value = node_vec->entries[node_index].data;
1415 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1416 edge = node->edges[edge_index];
1418 is_src = edge->src == node;
1421 vec = vector_copy(pbqp, edge->tgt->costs);
1422 vector_add_matrix_row(vec, mat, node_index);
1424 vec = vector_copy(pbqp, edge->src->costs);
1425 vector_add_matrix_col(vec, mat, node_index);
1428 value = pbqp_add(value, vector_get_min(vec));
1430 obstack_free(&pbqp->obstack, vec);
1435 min_index = node_index;
1442 int node_is_reduced(pbqp_node *node)
1444 if (!reduced_bucket) return 0;
1446 if (pbqp_node_get_degree(node) == 0) return 1;
1448 return node_bucket_contains(reduced_bucket, node);