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 num add(num x, num y)
22 if (x == INF_COSTS || y == INF_COSTS) return INF_COSTS;
27 static void init_buckets(void)
31 edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
32 reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
34 for (i = 0; i < 4; ++i) {
35 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
39 static void fill_node_buckets(pbqp *pbqp)
45 node_len = pbqp->num_nodes;
47 for (node_index = 0; node_index < node_len; ++node_index) {
49 pbqp_node *node = get_node(pbqp, node_index);
53 arity = ARR_LEN(node->edges);
55 /* We have only one bucket for nodes with arity >= 3. */
60 node->bucket_index = ARR_LEN(node_buckets[arity]);
62 ARR_APP1(pbqp_node *, node_buckets[arity], node);
68 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
87 src_vec = src_node->costs;
88 tgt_vec = tgt_node->costs;
92 src_len = src_vec->len;
93 tgt_len = tgt_vec->len;
100 /* Normalize towards source node. */
101 for (src_index = 0; src_index < src_len; ++src_index) {
102 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
105 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
106 src_vec->entries[src_index].data = add(
107 src_vec->entries[src_index].data, min);
109 // TODO add to edge_list if inf
114 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
128 src_node = edge->src;
129 tgt_node = edge->tgt;
133 src_vec = src_node->costs;
134 tgt_vec = tgt_node->costs;
138 src_len = src_vec->len;
139 tgt_len = tgt_vec->len;
146 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
147 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
150 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
151 tgt_vec->entries[tgt_index].data = add(
152 tgt_vec->entries[tgt_index].data, min);
154 // TODO add to edge_list if inf
159 static void reorder_node(pbqp_node *node)
163 unsigned old_bucket_len;
164 unsigned old_bucket_index;
165 pbqp_node **old_bucket;
168 if (!buckets_filled) return;
172 arity = ARR_LEN(node->edges);
174 /* Same bucket as before */
175 if (arity > 2) return;
177 /* Assume node lost one incident edge. */
178 old_arity = arity + 1;
179 old_bucket = node_buckets[old_arity];
180 old_bucket_len = ARR_LEN(old_bucket);
181 old_bucket_index = node->bucket_index;
183 if (old_bucket_len <= old_bucket_index ||
184 old_bucket[old_bucket_index] != node) {
185 /* Old arity is new arity, so we have nothing to do. */
186 assert(old_bucket_index < ARR_LEN(node_buckets[arity]) &&
187 node_buckets[arity][old_bucket_index] == node);
191 assert(old_bucket[old_bucket_index] == node);
193 /* Delete node from old bucket... */
194 other = old_bucket[old_bucket_len - 1];
195 other->bucket_index = old_bucket_index;
196 old_bucket[old_bucket_index] = other;
197 ARR_SHRINKLEN(node_buckets[old_arity], old_bucket_len - 1);
199 /* ..and add to new one. */
200 node->bucket_index = ARR_LEN(node_buckets[arity]);
201 ARR_APP1(pbqp_node*, node_buckets[arity], node);
204 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
217 src_node = edge->src;
218 tgt_node = edge->tgt;
222 if (pbqp->dump_file) {
224 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
225 dump_section(pbqp->dump_file, 3, txt);
228 src_vec = src_node->costs;
229 tgt_vec = tgt_node->costs;
233 src_len = src_vec->len;
234 tgt_len = tgt_vec->len;
241 if (pbqp->dump_file) {
242 fputs("Input:<br>\n", pbqp->dump_file);
243 dump_simplifyedge(pbqp, edge);
246 normalize_towards_source(pbqp, edge);
247 normalize_towards_target(pbqp, edge);
249 if (pbqp->dump_file) {
250 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
251 dump_simplifyedge(pbqp, edge);
254 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
255 if (pbqp->dump_file) {
256 fputs("edge has been eliminated", pbqp->dump_file);
259 reorder_node(src_node);
260 reorder_node(tgt_node);
265 void solve_pbqp_heuristical(pbqp *pbqp)
272 if (pbqp->dump_file) {
273 pbqp_dump_input(pbqp);
274 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
277 node_len = pbqp->num_nodes;
281 /* First simplify all edges. */
282 for (node_index = 0; node_index < node_len; ++node_index) {
284 pbqp_node *node = get_node(pbqp, node_index);
291 edge_len = ARR_LEN(edges);
293 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
294 pbqp_edge *edge = edges[edge_index];
296 /* Simplify only once per edge. */
297 if (node != edge->src) continue;
299 simplify_edge(pbqp, edge);
303 /* Put node into bucket representing their arity. */
304 fill_node_buckets(pbqp);
307 if (ARR_LEN(edge_bucket) > 0) {
308 panic("Please implement edge simplification");
309 } else if (ARR_LEN(node_buckets[1]) > 0) {
311 } else if (ARR_LEN(node_buckets[2]) > 0) {
312 panic("Please implement RII simplification");
313 } else if (ARR_LEN(node_buckets[3]) > 0) {
314 panic("Please implement RN simplification");
320 if (pbqp->dump_file) {
321 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
322 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
325 /* Solve trivial nodes and calculate solution. */
326 node_len = ARR_LEN(node_buckets[0]);
327 for (node_index = 0; node_index < node_len; ++node_index) {
328 pbqp_node *node = node_buckets[0][node_index];
331 node->solution = vector_get_min_index(node->costs);
332 pbqp->solution = add(pbqp->solution,
333 node->costs->entries[node->solution].data);
334 if (pbqp->dump_file) {
335 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
336 dump_node(pbqp, node);
340 if (pbqp->dump_file) {
341 dump_section(pbqp->dump_file, 2, "Minimum");
342 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
343 dump_section(pbqp->dump_file, 2, "Back Propagation");
346 /* Solve reduced nodes. */
347 node_len = ARR_LEN(reduced_bucket);
348 for (node_index = node_len; node_index > 0; --node_index) {
349 pbqp_node *node = reduced_bucket[node_index - 1];
352 switch (ARR_LEN(node->edges)) {
354 back_propagate_RI(pbqp, node);
357 panic("Please implement back propagation for RII");
360 panic("Only nodes with degree one or two should be in this bucket");
366 void applyRI(pbqp *pbqp)
368 pbqp_node **bucket = node_buckets[1];
369 unsigned bucket_len = ARR_LEN(bucket);
370 pbqp_node *node = bucket[bucket_len - 1];
371 pbqp_edge *edge = node->edges[0];
372 pbqp_matrix *mat = edge->costs;
373 int is_src = edge->src == node;
374 pbqp_node *other_node;
377 other_node = edge->tgt;
379 other_node = edge->src;
382 if (pbqp->dump_file) {
384 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
385 dump_section(pbqp->dump_file, 2, txt);
386 pbqp_dump_graph(pbqp);
387 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
388 dump_node(pbqp, node);
389 dump_node(pbqp, other_node);
390 dump_edge(pbqp, edge);
394 pbqp_matrix_add_to_all_cols(mat, node->costs);
395 normalize_towards_target(pbqp, edge);
397 pbqp_matrix_add_to_all_rows(mat, node->costs);
398 normalize_towards_source(pbqp, edge);
400 disconnect_edge(other_node, edge);
402 if (pbqp->dump_file) {
403 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
404 dump_node(pbqp, other_node);
407 /* Remove node from bucket... */
408 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
409 reorder_node(other_node);
411 /* ...and add it to back propagation list. */
412 node->bucket_index = ARR_LEN(reduced_bucket);
413 ARR_APP1(pbqp_node *, reduced_bucket, node);
416 void applyRII(pbqp *pbqp)
418 pbqp_node **bucket = node_buckets[1];
419 unsigned bucket_len = ARR_LEN(bucket);
420 pbqp_node *node = bucket[bucket_len - 1];
421 pbqp_edge *src_edge = node->edges[0];
422 pbqp_edge *tgt_edge = node->edges[1];
423 int src_is_src = src_edge->src == node;
424 int tgt_is_src = tgt_edge->src == node;
425 pbqp_matrix *src_mat;
426 pbqp_matrix *tgt_mat;
441 src_node = src_edge->tgt;
443 src_node = src_edge->src;
447 tgt_node = tgt_edge->tgt;
449 tgt_node = tgt_edge->src;
452 /* Swap nodes if necessary. */
453 if (tgt_node->index < src_node->index) {
465 src_is_src = src_edge->src == node;
466 tgt_is_src = tgt_edge->src == node;
469 src_mat = src_edge->costs;
470 tgt_mat = tgt_edge->costs;
472 src_vec = src_node->costs;
473 tgt_vec = tgt_node->costs;
474 node_vec = node->costs;
476 row_len = ARR_LEN(src_vec);
477 col_len = ARR_LEN(tgt_vec);
478 node_len = ARR_LEN(node_vec);
480 mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
482 for (row_index = 0; row_index < row_len; ++row_index) {
483 for (col_index = 0; col_index < col_len; ++col_index) {
484 vec = vector_copy(pbqp, node_vec);
487 vector_add_matrix_col(vec, src_mat, row_index);
489 vector_add_matrix_row(vec, src_mat, row_index);
493 vector_add_matrix_col(vec, tgt_mat, col_index);
495 vector_add_matrix_row(vec, tgt_mat, col_index);
498 mat->entries[row_index * col_len + col_index] = vector_get_min_index(vec);
502 pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
505 edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
507 pbqp_matrix_add(edge->costs, mat);
509 /* Free local matrix. */
510 obstack_free(&pbqp->obstack, mat);
513 /* Disconnect node. */
514 disconnect_edge(src_node, src_edge);
515 disconnect_edge(tgt_node, tgt_edge);
517 /* Edge has changed so we simplify it. */
518 simplify_edge(pbqp, edge);
521 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
532 edge = node->edges[0];
534 is_src = edge->src == node;
540 vector_add_matrix_col(vec, mat, other->solution);
544 vector_add_matrix_row(vec, mat, other->solution);
547 node->solution = vector_get_min_index(vec);
548 if (pbqp->dump_file) {
549 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
553 int node_is_reduced(pbqp_node *node)
555 if (!reduced_bucket) return 0;
558 if (ARR_LEN(node->edges) == 0) return 1;
560 unsigned bucket_length = ARR_LEN(reduced_bucket);
561 unsigned bucket_index = node->bucket_index;
563 return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;