5 #include "heuristical.h"
6 #include "html_dumper.h"
10 #include "pbqp_edge_t.h"
11 #include "pbqp_node.h"
12 #include "pbqp_node_t.h"
15 static pbqp_edge **edge_bucket;
16 static pbqp_node **node_buckets[4];
17 static pbqp_node **reduced_bucket = NULL;
18 static int buckets_filled = 0;
20 static void init_buckets(void)
24 edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
25 reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
27 for (i = 0; i < 4; ++i) {
28 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
32 static void fill_node_buckets(pbqp *pbqp)
38 node_len = pbqp->num_nodes;
40 for (node_index = 0; node_index < node_len; ++node_index) {
42 pbqp_node *node = get_node(pbqp, node_index);
46 arity = ARR_LEN(node->edges);
48 /* We have only one bucket for nodes with arity >= 3. */
53 node->bucket_index = ARR_LEN(node_buckets[arity]);
55 ARR_APP1(pbqp_node *, node_buckets[arity], node);
61 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
80 src_vec = src_node->costs;
81 tgt_vec = tgt_node->costs;
85 src_len = src_vec->len;
86 tgt_len = tgt_vec->len;
93 /* Normalize towards source node. */
94 for (src_index = 0; src_index < src_len; ++src_index) {
95 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
98 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
99 src_vec->entries[src_index].data = pbqp_add(
100 src_vec->entries[src_index].data, min);
102 // TODO add to edge_list if inf
107 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
121 src_node = edge->src;
122 tgt_node = edge->tgt;
126 src_vec = src_node->costs;
127 tgt_vec = tgt_node->costs;
131 src_len = src_vec->len;
132 tgt_len = tgt_vec->len;
139 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
140 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
143 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
144 tgt_vec->entries[tgt_index].data = pbqp_add(
145 tgt_vec->entries[tgt_index].data, min);
147 // TODO add to edge_list if inf
152 static void reorder_node(pbqp_node *node)
156 unsigned old_bucket_len;
157 unsigned old_bucket_index;
158 pbqp_node **old_bucket;
161 if (!buckets_filled) return;
165 arity = ARR_LEN(node->edges);
167 /* Same bucket as before */
168 if (arity > 2) return;
170 /* Assume node lost one incident edge. */
171 old_arity = arity + 1;
172 old_bucket = node_buckets[old_arity];
173 old_bucket_len = ARR_LEN(old_bucket);
174 old_bucket_index = node->bucket_index;
176 if (old_bucket_len <= old_bucket_index ||
177 old_bucket[old_bucket_index] != node) {
178 /* Old arity is new arity, so we have nothing to do. */
179 assert(old_bucket_index < ARR_LEN(node_buckets[arity]) &&
180 node_buckets[arity][old_bucket_index] == node);
184 assert(old_bucket[old_bucket_index] == node);
186 /* Delete node from old bucket... */
187 other = old_bucket[old_bucket_len - 1];
188 other->bucket_index = old_bucket_index;
189 old_bucket[old_bucket_index] = other;
190 ARR_SHRINKLEN(node_buckets[old_arity], old_bucket_len - 1);
192 /* ..and add to new one. */
193 node->bucket_index = ARR_LEN(node_buckets[arity]);
194 ARR_APP1(pbqp_node*, node_buckets[arity], node);
197 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
210 src_node = edge->src;
211 tgt_node = edge->tgt;
215 if (pbqp->dump_file) {
217 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
218 dump_section(pbqp->dump_file, 3, txt);
221 src_vec = src_node->costs;
222 tgt_vec = tgt_node->costs;
226 src_len = src_vec->len;
227 tgt_len = tgt_vec->len;
234 if (pbqp->dump_file) {
235 fputs("Input:<br>\n", pbqp->dump_file);
236 dump_simplifyedge(pbqp, edge);
239 normalize_towards_source(pbqp, edge);
240 normalize_towards_target(pbqp, edge);
242 if (pbqp->dump_file) {
243 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
244 dump_simplifyedge(pbqp, edge);
247 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
248 if (pbqp->dump_file) {
249 fputs("edge has been eliminated<br>\n", pbqp->dump_file);
253 reorder_node(src_node);
254 reorder_node(tgt_node);
258 void solve_pbqp_heuristical(pbqp *pbqp)
265 if (pbqp->dump_file) {
266 pbqp_dump_input(pbqp);
267 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
270 node_len = pbqp->num_nodes;
274 /* First simplify all edges. */
275 for (node_index = 0; node_index < node_len; ++node_index) {
277 pbqp_node *node = get_node(pbqp, node_index);
284 edge_len = ARR_LEN(edges);
286 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
287 pbqp_edge *edge = edges[edge_index];
289 /* Simplify only once per edge. */
290 if (node != edge->src) continue;
292 simplify_edge(pbqp, edge);
296 /* Put node into bucket representing their arity. */
297 fill_node_buckets(pbqp);
300 if (ARR_LEN(edge_bucket) > 0) {
301 panic("Please implement edge simplification");
302 } else if (ARR_LEN(node_buckets[1]) > 0) {
304 } else if (ARR_LEN(node_buckets[2]) > 0) {
306 } else if (ARR_LEN(node_buckets[3]) > 0) {
307 panic("Please implement RN simplification");
313 if (pbqp->dump_file) {
314 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
315 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
318 /* Solve trivial nodes and calculate solution. */
319 node_len = ARR_LEN(node_buckets[0]);
320 for (node_index = 0; node_index < node_len; ++node_index) {
321 pbqp_node *node = node_buckets[0][node_index];
324 node->solution = vector_get_min_index(node->costs);
325 pbqp->solution = pbqp_add(pbqp->solution,
326 node->costs->entries[node->solution].data);
327 if (pbqp->dump_file) {
328 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
329 dump_node(pbqp, node);
333 if (pbqp->dump_file) {
334 dump_section(pbqp->dump_file, 2, "Minimum");
335 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
336 dump_section(pbqp->dump_file, 2, "Back Propagation");
339 /* Solve reduced nodes. */
340 node_len = ARR_LEN(reduced_bucket);
341 for (node_index = node_len; node_index > 0; --node_index) {
342 pbqp_node *node = reduced_bucket[node_index - 1];
345 switch (ARR_LEN(node->edges)) {
347 back_propagate_RI(pbqp, node);
350 panic("Please implement back propagation for RII");
353 panic("Only nodes with degree one or two should be in this bucket");
359 void applyRI(pbqp *pbqp)
361 pbqp_node **bucket = node_buckets[1];
362 unsigned bucket_len = ARR_LEN(bucket);
363 pbqp_node *node = bucket[bucket_len - 1];
364 pbqp_edge *edge = node->edges[0];
365 pbqp_matrix *mat = edge->costs;
366 int is_src = edge->src == node;
367 pbqp_node *other_node;
370 other_node = edge->tgt;
372 other_node = edge->src;
375 if (pbqp->dump_file) {
377 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
378 dump_section(pbqp->dump_file, 2, txt);
379 pbqp_dump_graph(pbqp);
380 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
381 dump_node(pbqp, node);
382 dump_node(pbqp, other_node);
383 dump_edge(pbqp, edge);
387 pbqp_matrix_add_to_all_cols(mat, node->costs);
388 normalize_towards_target(pbqp, edge);
390 pbqp_matrix_add_to_all_rows(mat, node->costs);
391 normalize_towards_source(pbqp, edge);
393 disconnect_edge(other_node, edge);
395 if (pbqp->dump_file) {
396 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
397 dump_node(pbqp, other_node);
400 /* Remove node from bucket... */
401 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
402 reorder_node(other_node);
404 /* ...and add it to back propagation list. */
405 node->bucket_index = ARR_LEN(reduced_bucket);
406 ARR_APP1(pbqp_node *, reduced_bucket, node);
409 void applyRII(pbqp *pbqp)
411 pbqp_node **bucket = node_buckets[2];
412 unsigned bucket_len = ARR_LEN(bucket);
413 pbqp_node *node = bucket[bucket_len - 1];
414 pbqp_edge *src_edge = node->edges[0];
415 pbqp_edge *tgt_edge = node->edges[1];
416 int src_is_src = src_edge->src == node;
417 int tgt_is_src = tgt_edge->src == node;
418 pbqp_matrix *src_mat;
419 pbqp_matrix *tgt_mat;
436 src_node = src_edge->tgt;
438 src_node = src_edge->src;
442 tgt_node = tgt_edge->tgt;
444 tgt_node = tgt_edge->src;
447 /* Swap nodes if necessary. */
448 if (tgt_node->index < src_node->index) {
460 src_is_src = src_edge->src == node;
461 tgt_is_src = tgt_edge->src == node;
464 if (pbqp->dump_file) {
466 sprintf(txt, "RII-Reduktion of Node n%d", node->index);
467 dump_section(pbqp->dump_file, 2, txt);
468 pbqp_dump_graph(pbqp);
469 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
470 dump_node(pbqp, src_node);
471 dump_edge(pbqp, src_edge);
472 dump_node(pbqp, node);
473 dump_edge(pbqp, tgt_edge);
474 dump_node(pbqp, tgt_node);
477 src_mat = src_edge->costs;
478 tgt_mat = tgt_edge->costs;
480 src_vec = src_node->costs;
481 tgt_vec = tgt_node->costs;
482 node_vec = node->costs;
484 row_len = src_vec->len;
485 col_len = tgt_vec->len;
486 node_len = node_vec->len;
488 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
490 for (row_index = 0; row_index < row_len; ++row_index) {
491 for (col_index = 0; col_index < col_len; ++col_index) {
492 vec = vector_copy(pbqp, node_vec);
495 vector_add_matrix_col(vec, src_mat, row_index);
497 vector_add_matrix_row(vec, src_mat, row_index);
501 vector_add_matrix_col(vec, tgt_mat, col_index);
503 vector_add_matrix_row(vec, tgt_mat, col_index);
506 mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
510 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
512 /* Disconnect node. */
513 disconnect_edge(src_node, src_edge);
514 disconnect_edge(tgt_node, tgt_edge);
516 /* Remove node from bucket... */
517 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
519 /* ...and add it to back propagation list. */
520 node->bucket_index = ARR_LEN(reduced_bucket);
521 ARR_APP1(pbqp_node *, reduced_bucket, node);
524 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
526 pbqp_matrix_add(edge->costs, mat);
528 /* Free local matrix. */
529 obstack_free(&pbqp->obstack, mat);
531 reorder_node(src_node);
532 reorder_node(tgt_node);
535 if (pbqp->dump_file) {
536 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
537 dump_edge(pbqp, edge);
540 /* Edge has changed so we simplify it. */
541 simplify_edge(pbqp, edge);
544 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
555 edge = node->edges[0];
557 is_src = edge->src == node;
563 vector_add_matrix_col(vec, mat, other->solution);
567 vector_add_matrix_row(vec, mat, other->solution);
570 node->solution = vector_get_min_index(vec);
571 if (pbqp->dump_file) {
572 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
576 int node_is_reduced(pbqp_node *node)
578 if (!reduced_bucket) return 0;
581 if (ARR_LEN(node->edges) == 0) return 1;
583 unsigned bucket_length = ARR_LEN(reduced_bucket);
584 unsigned bucket_index = node->bucket_index;
586 return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;