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 += min;
101 // TODO add to edge_list if inf
106 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
120 src_node = edge->src;
121 tgt_node = edge->tgt;
125 src_vec = src_node->costs;
126 tgt_vec = tgt_node->costs;
130 src_len = src_vec->len;
131 tgt_len = tgt_vec->len;
138 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
139 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
142 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
143 tgt_vec->entries[tgt_index].data += min;
145 // TODO add to edge_list if inf
150 static void reorder_node(pbqp_node *node)
154 unsigned old_bucket_len;
156 if (!buckets_filled) return;
160 arity = ARR_LEN(node->edges);
162 /* Equal bucket as before */
163 if (arity > 2) return;
165 /* Assume node lost one incident edge. */
166 old_arity = arity + 1;
168 if (ARR_LEN(node_buckets[old_arity]) <= (int)node->bucket_index
169 || node_buckets[old_arity][node->bucket_index] != node) {
170 /* Old arity is new arity, so we have nothing to do. */
174 old_bucket_len = ARR_LEN(node_buckets[old_arity]);
175 assert (node_buckets[old_arity][node->bucket_index] == node);
177 /* Delete node from old bucket... */
178 node_buckets[old_arity][old_bucket_len - 1]->bucket_index
179 = node->bucket_index;
180 node_buckets[old_arity][node->bucket_index]
181 = node_buckets[old_arity][old_bucket_len - 1];
182 ARR_SHRINKLEN(node_buckets[old_arity], (int)old_bucket_len - 1);
184 /* ..and add to new one. */
185 node->bucket_index = ARR_LEN(node_buckets[arity]);
186 ARR_APP1(pbqp_node *, node_buckets[arity], node);
189 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
202 src_node = edge->src;
203 tgt_node = edge->tgt;
207 if(pbqp->dump_file) {
209 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
210 dump_section(pbqp->dump_file, 3, txt);
213 src_vec = src_node->costs;
214 tgt_vec = tgt_node->costs;
218 src_len = src_vec->len;
219 tgt_len = tgt_vec->len;
226 if (pbqp->dump_file) {
227 fputs("Input:<br>\n", pbqp->dump_file);
228 dump_simplifyedge(pbqp, edge);
231 normalize_towards_source(pbqp, edge);
232 normalize_towards_target(pbqp, edge);
234 if (pbqp->dump_file) {
235 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
236 dump_simplifyedge(pbqp, edge);
239 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
240 if (pbqp->dump_file) {
241 fputs("edge has been eliminated", pbqp->dump_file);
244 reorder_node(src_node);
245 reorder_node(tgt_node);
250 void solve_pbqp_heuristical(pbqp *pbqp)
257 if (pbqp->dump_file) {
258 pbqp_dump_input(pbqp);
259 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
262 node_len = pbqp->num_nodes;
266 /* First simplify all edges. */
267 for (node_index = 0; node_index < node_len; ++node_index) {
269 pbqp_node *node = get_node(pbqp, node_index);
276 edge_len = ARR_LEN(edges);
278 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
279 pbqp_edge *edge = edges[edge_index];
281 /* Simplify only once per edge. */
282 if (node_index != edge->src->index) continue;
284 simplify_edge(pbqp, edge);
288 /* Put node into bucket representing their arity. */
289 fill_node_buckets(pbqp);
292 if (ARR_LEN(edge_bucket) > 0) {
293 panic("Please implement edge simplification");
294 } else if (ARR_LEN(node_buckets[1]) > 0) {
296 } else if (ARR_LEN(node_buckets[2]) > 0) {
297 panic("Please implement RII simplification");
298 } else if (ARR_LEN(node_buckets[3]) > 0) {
299 panic("Please implement RN simplification");
305 if (pbqp->dump_file) {
306 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
307 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
310 /* Solve trivial nodes and calculate solution. */
311 node_len = ARR_LEN(node_buckets[0]);
312 for (node_index = 0; node_index < node_len; ++node_index) {
313 pbqp_node *node = node_buckets[0][node_index];
316 node->solution = vector_get_min_index(node->costs);
317 pbqp->solution += node->costs->entries[node->solution].data;
318 if (pbqp->dump_file) {
319 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
320 dump_node(pbqp, node);
324 if (pbqp->dump_file) {
325 dump_section(pbqp->dump_file, 2, "Minimum");
326 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
327 dump_section(pbqp->dump_file, 2, "Back Propagation");
330 /* Solve reduced nodes. */
331 node_len = ARR_LEN(reduced_bucket);
332 for (node_index = node_len; node_index > 0; --node_index) {
333 pbqp_node *node = reduced_bucket[node_index - 1];
336 switch (ARR_LEN(node->edges)) {
338 back_propagate_RI(pbqp, node);
341 panic("Please implement back propagation for RII");
344 panic("Only nodes with degree one or two should be in this bucket");
350 void applyRI(pbqp *pbqp)
352 pbqp_node **bucket = node_buckets[1];
353 unsigned bucket_len = ARR_LEN(bucket);
354 pbqp_node *node = bucket[bucket_len - 1];
355 pbqp_edge *edge = node->edges[0];
356 pbqp_matrix *mat = edge->costs;
357 int is_src = edge->src == node;
358 pbqp_node *other_node;
361 other_node = edge->tgt;
363 other_node = edge->src;
366 if (pbqp->dump_file) {
368 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
369 dump_section(pbqp->dump_file, 2, txt);
370 pbqp_dump_graph(pbqp);
371 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
372 dump_node(pbqp, node);
373 dump_node(pbqp, other_node);
374 dump_edge(pbqp, edge);
378 pbqp_matrix_add_to_all_cols(mat, node->costs);
379 normalize_towards_target(pbqp, edge);
381 pbqp_matrix_add_to_all_rows(mat, node->costs);
382 normalize_towards_source(pbqp, edge);
384 disconnect_edge(other_node, edge);
386 if (pbqp->dump_file) {
387 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
388 dump_node(pbqp, other_node);
391 /* Remove node from bucket... */
392 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
393 reorder_node(other_node);
395 /* ...and add it to back propagation list. */
396 node->bucket_index = ARR_LEN(reduced_bucket);
397 ARR_APP1(pbqp_node *, reduced_bucket, node);
400 void applyRII(pbqp *pbqp)
402 pbqp_node **bucket = node_buckets[1];
403 unsigned bucket_len = ARR_LEN(bucket);
404 pbqp_node *node = bucket[bucket_len - 1];
405 pbqp_edge *src_edge = node->edges[0];
406 pbqp_edge *tgt_edge = node->edges[1];
407 int src_is_src = src_edge->src == node;
408 int tgt_is_src = tgt_edge->src == node;
409 pbqp_matrix *src_mat;
410 pbqp_matrix *tgt_mat;
425 src_node = src_edge->tgt;
427 src_node = src_edge->src;
431 tgt_node = tgt_edge->tgt;
433 tgt_node = tgt_edge->src;
436 /* Swap nodes if necessary. */
437 if (tgt_node->index < src_node->index) {
449 src_is_src = src_edge->src == node;
450 tgt_is_src = tgt_edge->src == node;
453 src_mat = src_edge->costs;
454 tgt_mat = tgt_edge->costs;
456 src_vec = src_node->costs;
457 tgt_vec = tgt_node->costs;
458 node_vec = node->costs;
460 row_len = ARR_LEN(src_vec);
461 col_len = ARR_LEN(tgt_vec);
462 node_len = ARR_LEN(node_vec);
464 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
466 for (row_index = 0; row_index < row_len; ++row_index) {
467 for (col_index = 0; col_index < col_len; ++col_index) {
468 vec = vector_copy(pbqp, node_vec);
471 vector_add_matrix_col(vec, src_mat, row_index);
473 vector_add_matrix_row(vec, src_mat, row_index);
477 vector_add_matrix_col(vec, tgt_mat, col_index);
479 vector_add_matrix_row(vec, tgt_mat, col_index);
482 mat->entries[row_index * col_len + col_index] = vector_get_min_index(vec);
486 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
489 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
491 pbqp_matrix_add(edge->costs, mat);
493 /* Free local matrix. */
494 obstack_free(&pbqp->obstack, mat);
497 /* Disconnect node. */
498 disconnect_edge(src_node, src_edge);
499 disconnect_edge(tgt_node, tgt_edge);
501 /* Edge has changed so we simplify it. */
502 simplify_edge(pbqp, edge);
505 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
516 edge = node->edges[0];
518 is_src = edge->src == node;
524 vector_add_matrix_col(vec, mat, other->solution);
528 vector_add_matrix_row(vec, mat, other->solution);
531 node->solution = vector_get_min_index(vec);
532 if (pbqp->dump_file) {
533 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
537 int node_is_reduced(pbqp_node *node)
539 if (!reduced_bucket) return 0;
542 if (ARR_LEN(node->edges) == 0) return 1;
544 unsigned bucket_length = ARR_LEN(reduced_bucket);
545 unsigned bucket_index = node->bucket_index;
547 return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;