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;
19 static void init_buckets(void)
23 edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
24 reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
26 for (i = 0; i < 4; ++i) {
27 node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
31 static void fill_node_buckets(pbqp *pbqp)
37 node_len = pbqp->num_nodes;
39 for (node_index = 0; node_index < node_len; ++node_index) {
41 pbqp_node *node = get_node(pbqp, node_index);
45 arity = ARR_LEN(node->edges);
47 /* We have only one bucket for nodes with arity >= 3. */
52 node->bucket_index = ARR_LEN(node_buckets[arity]);
54 ARR_APP1(pbqp_node *, node_buckets[arity], node);
58 static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
77 src_vec = src_node->costs;
78 tgt_vec = tgt_node->costs;
82 src_len = src_vec->len;
83 tgt_len = tgt_vec->len;
90 /* Normalize towards source node. */
91 for (src_index = 0; src_index < src_len; ++src_index) {
92 num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
95 pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
96 src_vec->entries[src_index].data += min;
98 // TODO add to edge_list if inf
103 static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
117 src_node = edge->src;
118 tgt_node = edge->tgt;
122 src_vec = src_node->costs;
123 tgt_vec = tgt_node->costs;
127 src_len = src_vec->len;
128 tgt_len = tgt_vec->len;
135 for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
136 num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
139 pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
140 tgt_vec->entries[tgt_index].data += min;
142 // TODO add to edge_list if inf
147 static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
160 src_node = edge->src;
161 tgt_node = edge->tgt;
165 if(pbqp->dump_file) {
167 sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
168 dump_section(pbqp->dump_file, 3, txt);
171 src_vec = src_node->costs;
172 tgt_vec = tgt_node->costs;
176 src_len = src_vec->len;
177 tgt_len = tgt_vec->len;
184 if (pbqp->dump_file) {
185 fputs("Input:<br>\n", pbqp->dump_file);
186 dump_simplifyedge(pbqp, edge);
189 normalize_towards_source(pbqp, edge);
190 normalize_towards_target(pbqp, edge);
192 if (pbqp->dump_file) {
193 fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
194 dump_simplifyedge(pbqp, edge);
197 if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
198 if (pbqp->dump_file) {
199 fputs("edge has been eliminated", pbqp->dump_file);
206 static void reorder_node(pbqp_node *node)
210 unsigned old_bucket_len;
214 arity = ARR_LEN(node->edges);
216 /* Equal bucket as before */
217 if (arity > 2) return;
219 /* Assume node lost one incident edge. */
220 old_arity = arity + 1;
222 if (ARR_LEN(node_buckets[old_arity]) <= (int)node->bucket_index
223 || node_buckets[old_arity][node->bucket_index] != node) {
224 /* Old arity is new arity, so we have nothing to do. */
228 old_bucket_len = ARR_LEN(node_buckets[old_arity]);
229 assert (node_buckets[old_arity][node->bucket_index] == node);
231 /* Delete node from old bucket... */
232 node_buckets[old_arity][node->bucket_index]
233 = node_buckets[old_arity][old_bucket_len - 1];
234 ARR_SHRINKLEN(node_buckets[old_arity], (int)old_bucket_len - 1);
236 /* ..and add to new one. */
237 node->bucket_index = ARR_LEN(node_buckets[arity]);
238 ARR_APP1(pbqp_node *, node_buckets[arity], node);
241 void solve_pbqp_heuristical(pbqp *pbqp)
248 if (pbqp->dump_file) {
249 pbqp_dump_input(pbqp);
250 dump_section(pbqp->dump_file, 1, "2. Simplification of Cost Matrices");
253 node_len = pbqp->num_nodes;
257 /* First simplify all edges. */
258 for (node_index = 0; node_index < node_len; ++node_index) {
260 pbqp_node *node = get_node(pbqp, node_index);
267 edge_len = ARR_LEN(edges);
269 for (edge_index = 0; edge_index < edge_len; ++edge_index) {
270 pbqp_edge *edge = edges[edge_index];
272 /* Simplify only once per edge. */
273 if (node_index != edge->src->index) continue;
275 simplify_edge(pbqp, edge);
279 /* Put node into bucket representing their arity. */
280 fill_node_buckets(pbqp);
283 if (ARR_LEN(edge_bucket) > 0) {
284 panic("Please implement edge simplification");
285 } else if (ARR_LEN(node_buckets[1]) > 0) {
287 } else if (ARR_LEN(node_buckets[2]) > 0) {
288 panic("Please implement RII simplification");
289 } else if (ARR_LEN(node_buckets[3]) > 0) {
290 panic("Please implement RN simplification");
296 if (pbqp->dump_file) {
297 dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
298 dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
301 /* Solve trivial nodes and calculate solution. */
302 node_len = ARR_LEN(node_buckets[0]);
303 for (node_index = 0; node_index < node_len; ++node_index) {
304 pbqp_node *node = node_buckets[0][node_index];
307 node->solution = vector_get_min_index(node->costs);
308 pbqp->solution += node->costs->entries[node->solution].data;
309 if (pbqp->dump_file) {
310 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
311 dump_node(pbqp, node);
315 if (pbqp->dump_file) {
316 dump_section(pbqp->dump_file, 2, "Minimum");
317 fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
318 dump_section(pbqp->dump_file, 2, "Back Propagation");
321 /* Solve reduced nodes. */
322 node_len = ARR_LEN(reduced_bucket);
323 for (node_index = node_len; node_index > 0; --node_index) {
324 pbqp_node *node = reduced_bucket[node_index - 1];
327 switch (ARR_LEN(node->edges)) {
329 back_propagate_RI(pbqp, node);
332 panic("Please implement back propagation for RII");
335 panic("Only nodes with degree one or two should be in this bucket");
341 void applyRI(pbqp *pbqp)
343 pbqp_node **bucket = node_buckets[1];
344 unsigned bucket_len = ARR_LEN(bucket);
345 pbqp_node *node = bucket[bucket_len - 1];
346 pbqp_edge *edge = node->edges[0];
347 pbqp_matrix *mat = edge->costs;
348 int is_src = edge->src == node;
349 pbqp_node *other_node;
352 other_node = edge->tgt;
354 other_node = edge->src;
357 if (pbqp->dump_file) {
359 sprintf(txt, "RI-Reduktion of Node n%d", node->index);
360 dump_section(pbqp->dump_file, 2, txt);
361 pbqp_dump_graph(pbqp);
362 fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
363 dump_node(pbqp, node);
364 dump_node(pbqp, other_node);
365 dump_edge(pbqp, edge);
369 pbqp_matrix_add_to_all_cols(mat, node->costs);
370 normalize_towards_target(pbqp, edge);
372 pbqp_matrix_add_to_all_rows(mat, node->costs);
373 dump_edge(pbqp, edge);
374 normalize_towards_source(pbqp, edge);
376 disconnect_edge(other_node, edge);
378 if (pbqp->dump_file) {
379 fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
380 dump_node(pbqp, other_node);
383 /* Remove node from bucket... */
384 ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
385 reorder_node(other_node);
387 /* ...and add it to back propagation list. */
388 ARR_APP1(pbqp_node *, reduced_bucket, node);
391 void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
402 edge = node->edges[0];
404 is_src = edge->src == node;
410 vector_add_matrix_col(vec, mat, other->solution);
414 vector_add_matrix_row(vec, mat, other->solution);
417 node->solution = vector_get_min_index(vec);
418 if (pbqp->dump_file) {
419 fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);