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 static int buckets_filled = 0;
55 static void insert_into_edge_bucket(pbqp_edge *edge)
57 if (edge_bucket_contains(edge_bucket, edge)) {
58 /* Edge is already inserted. */
62 edge_bucket_insert(&edge_bucket, edge);
65 static void insert_into_rm_bucket(pbqp_edge *edge)
67 if (edge_bucket_contains(rm_bucket, edge)) {
68 /* Edge is already inserted. */
72 edge_bucket_insert(&rm_bucket, edge);
75 static void init_buckets(void)
79 edge_bucket_init(&edge_bucket);
80 edge_bucket_init(&rm_bucket);
81 node_bucket_init(&reduced_bucket);
83 for (i = 0; i < 4; ++i) {
84 node_bucket_init(&node_buckets[i]);
88 void free_buckets(void)
92 for (i = 0; i < 4; ++i) {
93 node_bucket_free(&node_buckets[i]);
96 edge_bucket_free(&edge_bucket);
97 edge_bucket_free(&rm_bucket);
98 node_bucket_free(&reduced_bucket);
103 void fill_node_buckets(pbqp *pbqp)
109 node_len = pbqp->num_nodes;
112 ir_timer_t *t_fill_buckets = ir_timer_new();
113 ir_timer_start(t_fill_buckets);
116 for (node_index = 0; node_index < node_len; ++node_index) {
118 pbqp_node *node = get_node(pbqp, node_index);
122 degree = pbqp_node_get_degree(node);
124 /* We have only one bucket for nodes with arity >= 3. */
129 node_bucket_insert(&node_buckets[degree], node);
135 ir_timer_stop(t_fill_buckets);
136 printf("PBQP Fill Nodes into buckets: %8.3lf msec\n", (double)ir_timer_elapsed_usec(t_fill_buckets) / 1000.0);
140 static void normalize_towards_source(pbqp_edge *edge)
150 unsigned new_infinity = 0;
154 src_node = edge->src;
155 tgt_node = edge->tgt;
159 src_vec = src_node->costs;
160 tgt_vec = tgt_node->costs;
164 src_len = src_vec->len;
165 tgt_len = tgt_vec->len;
172 /* Normalize towards source node. */
173 for (src_index = 0; src_index < src_len; ++src_index) {
174 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
177 if (src_vec->entries[src_index].data == INF_COSTS) {
178 pbqp_matrix_set_row_value(mat, src_index, 0);
182 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
183 src_vec->entries[src_index].data = pbqp_add(
184 src_vec->entries[src_index].data, min);
186 if (min == INF_COSTS) {
194 unsigned edge_len = pbqp_node_get_degree(src_node);
196 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
197 pbqp_edge *edge_candidate = src_node->edges[edge_index];
199 if (edge_candidate != edge) {
200 insert_into_edge_bucket(edge_candidate);
206 static void normalize_towards_target(pbqp_edge *edge)
216 unsigned new_infinity = 0;
220 src_node = edge->src;
221 tgt_node = edge->tgt;
225 src_vec = src_node->costs;
226 tgt_vec = tgt_node->costs;
230 src_len = src_vec->len;
231 tgt_len = tgt_vec->len;
238 /* Normalize towards target node. */
239 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
240 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
243 if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
244 pbqp_matrix_set_col_value(mat, tgt_index, 0);
248 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
249 tgt_vec->entries[tgt_index].data = pbqp_add(
250 tgt_vec->entries[tgt_index].data, min);
252 if (min == INF_COSTS) {
260 unsigned edge_len = pbqp_node_get_degree(tgt_node);
262 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
263 pbqp_edge *edge_candidate = tgt_node->edges[edge_index];
265 if (edge_candidate != edge) {
266 insert_into_edge_bucket(edge_candidate);
273 * Tries to apply RM for the source node of the given edge.
275 * Checks whether the source node of edge can be merged into the target node of
276 * edge, and performs the merge, if possible.
278 static void merge_source_into_target(pbqp *pbqp, pbqp_edge *edge)
296 src_node = edge->src;
297 tgt_node = edge->tgt;
301 src_vec = src_node->costs;
302 tgt_vec = tgt_node->costs;
306 src_len = src_vec->len;
307 tgt_len = tgt_vec->len;
309 /* Matrizes are normalized. */
316 mapping = NEW_ARR_F(unsigned, tgt_len);
318 /* Check that each column has at most one zero entry. */
319 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
320 unsigned onlyOneZero = 0;
322 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
325 for (src_index = 0; src_index < src_len; ++src_index) {
326 if (src_vec->entries[src_index].data == INF_COSTS)
329 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS)
332 /* Matrix entry is finite. */
339 mapping[tgt_index] = src_index;
343 /* We know that we can merge the source node into the target node. */
344 edge_len = pbqp_node_get_degree(src_node);
350 /* Reconnect the source's edges with the target node. */
351 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
352 pbqp_edge *old_edge = src_node->edges[edge_index];
354 pbqp_matrix *old_matrix;
355 pbqp_matrix *new_matrix;
356 pbqp_node *other_node;
359 unsigned other_index;
364 if (old_edge == edge)
367 old_matrix = old_edge->costs;
370 if (old_edge->tgt == src_node) {
371 other_node = old_edge->src;
372 other_len = old_matrix->rows;
375 other_node = old_edge->tgt;
376 other_len = old_matrix->cols;
379 other_vec = other_node->costs;
381 new_matrix = pbqp_matrix_alloc(pbqp, tgt_len, other_len);
383 /* Source node selects the column of the old_matrix. */
384 if (old_edge->tgt == src_node) {
385 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
386 unsigned src_index = mapping[tgt_index];
388 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
391 for (other_index = 0; other_index < other_len; ++other_index) {
392 if (other_vec->entries[other_index].data == INF_COSTS)
395 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[other_index*src_len+src_index];
399 /* Source node selects the row of the old_matrix. */
401 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
402 unsigned src_index = mapping[tgt_index];
404 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
407 for (other_index = 0; other_index < other_len; ++other_index) {
408 if (other_vec->entries[other_index].data == INF_COSTS)
411 new_matrix->entries[tgt_index*other_len+other_index] = old_matrix->entries[src_index*other_len+other_index];
416 add_edge_costs(pbqp, tgt_node->index, other_node->index, new_matrix);
418 delete_edge(old_edge);
419 reorder_node(src_node);
420 reorder_node(other_node);
422 new_edge = get_edge(pbqp, tgt_node->index, other_node->index);
423 insert_into_rm_bucket(new_edge);
426 /* Reduce the remaining source node via RI. */
435 * Tries to apply RM for the target node of the given edge.
437 * Checks whether the target node of edge can be merged into the source node of
438 * edge, and performs the merge, if possible.
440 static void merge_target_into_source(pbqp *pbqp, pbqp_edge *edge)
458 src_node = edge->src;
459 tgt_node = edge->tgt;
463 src_vec = src_node->costs;
464 tgt_vec = tgt_node->costs;
468 src_len = src_vec->len;
469 tgt_len = tgt_vec->len;
471 /* Matrizes are normalized. */
478 mapping = NEW_ARR_F(unsigned, src_len);
480 /* Check that each row has at most one zero entry. */
481 for (src_index = 0; src_index < src_len; ++src_index) {
482 unsigned onlyOneZero = 0;
484 if (src_vec->entries[src_index].data == INF_COSTS)
487 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
488 if (tgt_vec->entries[tgt_index].data == INF_COSTS)
491 if (mat->entries[src_index * tgt_len + tgt_index] == INF_COSTS)
494 /* Matrix entry is finite. */
501 mapping[src_index] = tgt_index;
505 /* We know that we can merge the target node into the source node. */
506 edge_len = pbqp_node_get_degree(tgt_node);
512 /* Reconnect the target's edges with the source node. */
513 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
514 pbqp_edge *old_edge = tgt_node->edges[edge_index];
516 pbqp_matrix *old_matrix;
517 pbqp_matrix *new_matrix;
518 pbqp_node *other_node;
521 unsigned other_index;
526 if (old_edge == edge)
529 old_matrix = old_edge->costs;
532 if (old_edge->tgt == tgt_node) {
533 other_node = old_edge->src;
534 other_len = old_matrix->rows;
537 other_node = old_edge->tgt;
538 other_len = old_matrix->cols;
541 other_vec = other_node->costs;
543 new_matrix = pbqp_matrix_alloc(pbqp, src_len, other_len);
545 /* Target node selects the column of the old_matrix. */
546 if (old_edge->tgt == tgt_node) {
547 for (src_index = 0; src_index < src_len; ++src_index) {
548 unsigned tgt_index = mapping[src_index];
550 if (src_vec->entries[src_index].data == INF_COSTS)
553 for (other_index = 0; other_index < other_len; ++other_index) {
554 if (other_vec->entries[other_index].data == INF_COSTS)
557 new_matrix->entries[src_index*other_len+other_index] = old_matrix->entries[other_index*tgt_len+tgt_index];
561 /* Source node selects the row of the old_matrix. */
563 for (src_index = 0; src_index < src_len; ++src_index) {
564 unsigned tgt_index = mapping[src_index];
566 if (src_vec->entries[src_index].data == INF_COSTS)
569 for (other_index = 0; other_index < other_len; ++other_index) {
570 if (other_vec->entries[other_index].data == INF_COSTS)
573 new_matrix->entries[src_index*other_len+other_index] = old_matrix->entries[tgt_index*other_len+other_index];
578 add_edge_costs(pbqp, src_node->index, other_node->index, new_matrix);
580 delete_edge(old_edge);
581 reorder_node(tgt_node);
582 reorder_node(other_node);
584 new_edge = get_edge(pbqp, src_node->index, other_node->index);
585 insert_into_rm_bucket(new_edge);
588 /* Reduce the remaining source node via RI. */
597 * Merge neighbors into the given node.
599 void apply_RM(pbqp *pbqp, pbqp_node *node)
609 edge_len = pbqp_node_get_degree(node);
611 /* Check all incident edges. */
612 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
613 pbqp_edge *edge = edges[edge_index];
615 insert_into_rm_bucket(edge);
618 /* ALAP: Merge neighbors into given node. */
619 while(edge_bucket_get_length(rm_bucket) > 0) {
620 pbqp_edge *edge = edge_bucket_pop(&rm_bucket);
623 if (edge->src == node)
624 merge_target_into_source(pbqp, edge);
626 merge_source_into_target(pbqp, edge);
630 void reorder_node(pbqp_node *node)
632 unsigned degree = pbqp_node_get_degree(node);
633 /* Assume node lost one incident edge. */
634 unsigned old_degree = degree + 1;
636 if (!buckets_filled) return;
638 /* Same bucket as before */
639 if (degree > 2) return;
641 if (!node_bucket_contains(node_buckets[old_degree], node)) {
642 /* Old arity is new arity, so we have nothing to do. */
643 assert(node_bucket_contains(node_buckets[degree], node));
647 /* Delete node from old bucket... */
648 node_bucket_remove(&node_buckets[old_degree], node);
650 /* ..and add to new one. */
651 node_bucket_insert(&node_buckets[degree], node);
654 void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
667 src_node = edge->src;
668 tgt_node = edge->tgt;
672 /* If edge are already deleted, we have nothing to do. */
673 if (!is_connected(src_node, edge) || !is_connected(tgt_node, edge))
677 if (pbqp->dump_file) {
679 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
680 dump_section(pbqp->dump_file, 3, txt);
684 src_vec = src_node->costs;
685 tgt_vec = tgt_node->costs;
689 src_len = src_vec->len;
690 tgt_len = tgt_vec->len;
698 if (pbqp->dump_file) {
699 fputs("Input:<br>\n", pbqp->dump_file);
700 dump_simplifyedge(pbqp, edge);
704 normalize_towards_source(edge);
705 normalize_towards_target(edge);
708 if (pbqp->dump_file) {
709 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
710 dump_simplifyedge(pbqp, edge);
714 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
716 if (pbqp->dump_file) {
717 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
726 reorder_node(src_node);
727 reorder_node(tgt_node);
731 void initial_simplify_edges(pbqp *pbqp)
739 ir_timer_t *t_int_simpl = ir_timer_new();
740 ir_timer_start(t_int_simpl);
744 if (pbqp->dump_file) {
745 pbqp_dump_input(pbqp);
746 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
750 node_len = pbqp->num_nodes;
754 /* First simplify all edges. */
755 for (node_index = 0; node_index < node_len; ++node_index) {
757 pbqp_node *node = get_node(pbqp, node_index);
764 edge_len = pbqp_node_get_degree(node);
766 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
767 pbqp_edge *edge = edges[edge_index];
769 /* Simplify only once per edge. */
770 if (node != edge->src) continue;
772 simplify_edge(pbqp, edge);
777 ir_timer_stop(t_int_simpl);
778 printf("PBQP Initial simplify edges: %8.3lf msec\n", (double)ir_timer_elapsed_usec(t_int_simpl) / 1000.0);
782 num determine_solution(pbqp *pbqp)
789 ir_timer_t *t_det_solution = ir_timer_new();
790 ir_timer_reset_and_start(t_det_solution);
800 file = pbqp->dump_file;
803 dump_section(file, 1, "4. Determine Solution/Minimum");
804 dump_section(file, 2, "4.1. Trivial Solution");
808 /* Solve trivial nodes and calculate solution. */
809 node_len = node_bucket_get_length(node_buckets[0]);
812 pbqp->num_r0 = node_len;
815 for (node_index = 0; node_index < node_len; ++node_index) {
816 pbqp_node *node = node_buckets[0][node_index];
819 node->solution = vector_get_min_index(node->costs);
820 solution = pbqp_add(solution,
821 node->costs->entries[node->solution].data);
825 fprintf(file, "node n%d is set to %d<br>\n", node->index, node->solution);
826 dump_node(file, node);
833 dump_section(file, 2, "Minimum");
834 #if KAPS_USE_UNSIGNED
835 fprintf(file, "Minimum is equal to %u.", solution);
837 fprintf(file, "Minimum is equal to %lld.", solution);
843 ir_timer_stop(t_det_solution);
844 printf("PBQP Determine Solution: %8.3lf msec\n", (double)ir_timer_elapsed_usec(t_det_solution) / 1000.0);
850 static void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
861 edge = node->edges[0];
863 is_src = edge->src == node;
870 node->solution = pbqp_matrix_get_col_min_index(mat, other->solution, vec);
875 node->solution = pbqp_matrix_get_row_min_index(mat, other->solution, vec);
879 if (pbqp->dump_file) {
880 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
885 static void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
887 pbqp_edge *src_edge = node->edges[0];
888 pbqp_edge *tgt_edge = node->edges[1];
889 int src_is_src = src_edge->src == node;
890 int tgt_is_src = tgt_edge->src == node;
891 pbqp_matrix *src_mat;
892 pbqp_matrix *tgt_mat;
903 src_node = src_edge->tgt;
905 src_node = src_edge->src;
909 tgt_node = tgt_edge->tgt;
911 tgt_node = tgt_edge->src;
914 /* Swap nodes if necessary. */
915 if (tgt_node->index < src_node->index) {
927 src_is_src = src_edge->src == node;
928 tgt_is_src = tgt_edge->src == node;
931 src_mat = src_edge->costs;
932 tgt_mat = tgt_edge->costs;
934 node_vec = node->costs;
936 row_index = src_node->solution;
937 col_index = tgt_node->solution;
939 vec = vector_copy(pbqp, node_vec);
942 vector_add_matrix_col(vec, src_mat, row_index);
944 vector_add_matrix_row(vec, src_mat, row_index);
948 vector_add_matrix_col(vec, tgt_mat, col_index);
950 vector_add_matrix_row(vec, tgt_mat, col_index);
953 node->solution = vector_get_min_index(vec);
956 if (pbqp->dump_file) {
957 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
961 obstack_free(&pbqp->obstack, vec);
964 void back_propagate(pbqp *pbqp)
967 unsigned node_len = node_bucket_get_length(reduced_bucket);
972 if (pbqp->dump_file) {
973 dump_section(pbqp->dump_file, 2, "Back Propagation");
977 for (node_index = node_len; node_index > 0; --node_index) {
978 pbqp_node *node = reduced_bucket[node_index - 1];
980 switch (pbqp_node_get_degree(node)) {
982 back_propagate_RI(pbqp, node);
985 back_propagate_RII(pbqp, node);
988 panic("Only nodes with degree one or two should be in this bucket");
994 void apply_edge(pbqp *pbqp)
996 pbqp_edge *edge = edge_bucket_pop(&edge_bucket);
998 simplify_edge(pbqp, edge);
1001 void apply_RI(pbqp *pbqp)
1003 pbqp_node *node = node_bucket_pop(&node_buckets[1]);
1004 pbqp_edge *edge = node->edges[0];
1005 pbqp_matrix *mat = edge->costs;
1006 int is_src = edge->src == node;
1007 pbqp_node *other_node;
1010 assert(pbqp_node_get_degree(node) == 1);
1013 other_node = edge->tgt;
1015 other_node = edge->src;
1019 if (pbqp->dump_file) {
1021 sprintf(txt, "RI-Reduction of Node n%d", node->index);
1022 dump_section(pbqp->dump_file, 2, txt);
1023 pbqp_dump_graph(pbqp);
1024 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1025 dump_node(pbqp->dump_file, node);
1026 dump_node(pbqp->dump_file, other_node);
1027 dump_edge(pbqp->dump_file, edge);
1032 pbqp_matrix_add_to_all_cols(mat, node->costs);
1033 normalize_towards_target(edge);
1035 pbqp_matrix_add_to_all_rows(mat, node->costs);
1036 normalize_towards_source(edge);
1038 disconnect_edge(other_node, edge);
1041 if (pbqp->dump_file) {
1042 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1043 dump_node(pbqp->dump_file, other_node);
1047 reorder_node(other_node);
1053 /* Add node to back propagation list. */
1054 node_bucket_insert(&reduced_bucket, node);
1057 void apply_RII(pbqp *pbqp)
1059 pbqp_node *node = node_bucket_pop(&node_buckets[2]);
1060 pbqp_edge *src_edge = node->edges[0];
1061 pbqp_edge *tgt_edge = node->edges[1];
1062 int src_is_src = src_edge->src == node;
1063 int tgt_is_src = tgt_edge->src == node;
1064 pbqp_matrix *src_mat;
1065 pbqp_matrix *tgt_mat;
1066 pbqp_node *src_node;
1067 pbqp_node *tgt_node;
1080 assert(pbqp_node_get_degree(node) == 2);
1083 src_node = src_edge->tgt;
1085 src_node = src_edge->src;
1089 tgt_node = tgt_edge->tgt;
1091 tgt_node = tgt_edge->src;
1094 /* Swap nodes if necessary. */
1095 if (tgt_node->index < src_node->index) {
1096 pbqp_node *tmp_node;
1097 pbqp_edge *tmp_edge;
1099 tmp_node = src_node;
1100 src_node = tgt_node;
1101 tgt_node = tmp_node;
1103 tmp_edge = src_edge;
1104 src_edge = tgt_edge;
1105 tgt_edge = tmp_edge;
1107 src_is_src = src_edge->src == node;
1108 tgt_is_src = tgt_edge->src == node;
1112 if (pbqp->dump_file) {
1114 sprintf(txt, "RII-Reduction of Node n%d", node->index);
1115 dump_section(pbqp->dump_file, 2, txt);
1116 pbqp_dump_graph(pbqp);
1117 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
1118 dump_node(pbqp->dump_file, src_node);
1119 dump_edge(pbqp->dump_file, src_edge);
1120 dump_node(pbqp->dump_file, node);
1121 dump_edge(pbqp->dump_file, tgt_edge);
1122 dump_node(pbqp->dump_file, tgt_node);
1126 src_mat = src_edge->costs;
1127 tgt_mat = tgt_edge->costs;
1129 src_vec = src_node->costs;
1130 tgt_vec = tgt_node->costs;
1131 node_vec = node->costs;
1133 row_len = src_vec->len;
1134 col_len = tgt_vec->len;
1135 node_len = node_vec->len;
1137 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
1139 for (row_index = 0; row_index < row_len; ++row_index) {
1140 for (col_index = 0; col_index < col_len; ++col_index) {
1141 vec = vector_copy(pbqp, node_vec);
1144 vector_add_matrix_col(vec, src_mat, row_index);
1146 vector_add_matrix_row(vec, src_mat, row_index);
1150 vector_add_matrix_col(vec, tgt_mat, col_index);
1152 vector_add_matrix_row(vec, tgt_mat, col_index);
1155 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
1157 obstack_free(&pbqp->obstack, vec);
1161 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
1163 /* Disconnect node. */
1164 disconnect_edge(src_node, src_edge);
1165 disconnect_edge(tgt_node, tgt_edge);
1171 /* Add node to back propagation list. */
1172 node_bucket_insert(&reduced_bucket, node);
1175 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
1178 pbqp_matrix_add(edge->costs, mat);
1180 /* Free local matrix. */
1181 obstack_free(&pbqp->obstack, mat);
1183 reorder_node(src_node);
1184 reorder_node(tgt_node);
1188 if (pbqp->dump_file) {
1189 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
1190 dump_edge(pbqp->dump_file, edge);
1194 /* Edge has changed so we simplify it. */
1195 simplify_edge(pbqp, edge);
1198 static void select_column(pbqp_edge *edge, unsigned col_index)
1201 pbqp_node *src_node;
1202 pbqp_node *tgt_node;
1208 unsigned new_infinity = 0;
1212 src_node = edge->src;
1213 tgt_node = edge->tgt;
1217 src_vec = src_node->costs;
1218 tgt_vec = tgt_node->costs;
1222 src_len = src_vec->len;
1223 tgt_len = tgt_vec->len;
1224 assert(src_len > 0);
1225 assert(tgt_len > 0);
1230 for (src_index = 0; src_index < src_len; ++src_index) {
1231 num elem = mat->entries[src_index * tgt_len + col_index];
1234 if (elem == INF_COSTS && src_vec->entries[src_index].data != INF_COSTS)
1237 src_vec->entries[src_index].data = pbqp_add(
1238 src_vec->entries[src_index].data, elem);
1243 unsigned edge_index;
1244 unsigned edge_len = pbqp_node_get_degree(src_node);
1246 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1247 pbqp_edge *edge_candidate = src_node->edges[edge_index];
1249 if (edge_candidate != edge) {
1250 insert_into_edge_bucket(edge_candidate);
1256 reorder_node(src_node);
1257 reorder_node(tgt_node);
1260 static void select_row(pbqp_edge *edge, unsigned row_index)
1263 pbqp_node *src_node;
1264 pbqp_node *tgt_node;
1268 unsigned new_infinity = 0;
1272 src_node = edge->src;
1273 tgt_node = edge->tgt;
1276 tgt_vec = tgt_node->costs;
1279 tgt_len = tgt_vec->len;
1280 assert(tgt_len > 0);
1285 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
1286 num elem = mat->entries[row_index * tgt_len + tgt_index];
1289 if (elem == INF_COSTS && tgt_vec->entries[tgt_index].data != INF_COSTS)
1292 tgt_vec->entries[tgt_index].data = pbqp_add(
1293 tgt_vec->entries[tgt_index].data, elem);
1298 unsigned edge_index;
1299 unsigned edge_len = pbqp_node_get_degree(tgt_node);
1301 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
1302 pbqp_edge *edge_candidate = tgt_node->edges[edge_index];
1304 if (edge_candidate != edge) {
1305 insert_into_edge_bucket(edge_candidate);
1311 reorder_node(src_node);
1312 reorder_node(tgt_node);
1315 void select_alternative(pbqp_node *node, unsigned selected_index)
1317 unsigned edge_index;
1318 unsigned node_index;
1321 unsigned max_degree = pbqp_node_get_degree(node);
1324 node->solution = selected_index;
1325 node_vec = node->costs;
1326 node_len = node_vec->len;
1327 assert(selected_index < node_len);
1329 /* Set all other costs to infinity. */
1330 for (node_index = 0; node_index < node_len; ++node_index) {
1331 if (node_index != selected_index) {
1332 node_vec->entries[node_index].data = INF_COSTS;
1336 /* Select corresponding row/column for incident edges. */
1337 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1338 pbqp_edge *edge = node->edges[edge_index];
1340 if (edge->src == node)
1341 select_row(edge, selected_index);
1343 select_column(edge, selected_index);
1347 pbqp_node *get_node_with_max_degree(void)
1349 pbqp_node **bucket = node_buckets[3];
1350 unsigned bucket_len = node_bucket_get_length(bucket);
1351 unsigned bucket_index;
1352 unsigned max_degree = 0;
1353 pbqp_node *result = NULL;
1355 for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
1356 pbqp_node *candidate = bucket[bucket_index];
1357 unsigned degree = pbqp_node_get_degree(candidate);
1359 if (degree > max_degree) {
1361 max_degree = degree;
1368 unsigned get_local_minimal_alternative(pbqp *pbqp, pbqp_node *node)
1374 unsigned edge_index;
1375 unsigned max_degree;
1376 unsigned node_index;
1378 unsigned min_index = 0;
1379 num min = INF_COSTS;
1384 node_vec = node->costs;
1385 node_len = node_vec->len;
1386 max_degree = pbqp_node_get_degree(node);
1388 for (node_index = 0; node_index < node_len; ++node_index) {
1389 num value = node_vec->entries[node_index].data;
1391 for (edge_index = 0; edge_index < max_degree; ++edge_index) {
1392 edge = node->edges[edge_index];
1394 is_src = edge->src == node;
1397 vec = vector_copy(pbqp, edge->tgt->costs);
1398 vector_add_matrix_row(vec, mat, node_index);
1400 vec = vector_copy(pbqp, edge->src->costs);
1401 vector_add_matrix_col(vec, mat, node_index);
1404 value = pbqp_add(value, vector_get_min(vec));
1406 obstack_free(&pbqp->obstack, vec);
1411 min_index = node_index;
1418 int node_is_reduced(pbqp_node *node)
1420 if (!reduced_bucket) return 0;
1422 if (pbqp_node_get_degree(node) == 0) return 1;
1424 return node_bucket_contains(reduced_bucket, node);