static pbqp_node **reduced_bucket = NULL;
static int buckets_filled = 0;
+/* Forward declarations. */
+static void apply_Brute_Force(pbqp *pbqp);
+
static void insert_into_edge_bucket(pbqp_edge *edge)
{
if (edge_bucket_contains(edge_bucket, edge)) {
node_len = pbqp->num_nodes;
for (node_index = 0; node_index < node_len; ++node_index) {
- unsigned arity;
+ unsigned degree;
pbqp_node *node = get_node(pbqp, node_index);
if (!node) continue;
- arity = ARR_LEN(node->edges);
+ degree = pbqp_node_get_degree(node);
/* We have only one bucket for nodes with arity >= 3. */
- if (arity > 3) {
- arity = 3;
+ if (degree > 3) {
+ degree = 3;
}
- node_bucket_insert(&node_buckets[arity], node);
+ node_bucket_insert(&node_buckets[degree], node);
}
buckets_filled = 1;
if (min == INF_COSTS) {
unsigned edge_index;
- unsigned edge_len = ARR_LEN(src_node->edges);
+ unsigned edge_len = pbqp_node_get_degree(src_node);
for (edge_index = 0; edge_index < edge_len; ++edge_index) {
pbqp_edge *edge_candidate = src_node->edges[edge_index];
if (min == INF_COSTS) {
unsigned edge_index;
- unsigned edge_len = ARR_LEN(tgt_node->edges);
+ unsigned edge_len = pbqp_node_get_degree(tgt_node);
for (edge_index = 0; edge_index < edge_len; ++edge_index) {
pbqp_edge *edge_candidate = tgt_node->edges[edge_index];
static void reorder_node(pbqp_node *node)
{
- unsigned arity;
- unsigned old_arity;
- unsigned old_bucket_len;
- unsigned old_bucket_index;
- pbqp_node **old_bucket;
+ unsigned degree = pbqp_node_get_degree(node);
+ /* Assume node lost one incident edge. */
+ unsigned old_degree = degree + 1;
if (!buckets_filled) return;
- assert(node);
-
- arity = ARR_LEN(node->edges);
-
/* Same bucket as before */
- if (arity > 2) return;
-
- /* Assume node lost one incident edge. */
- old_arity = arity + 1;
- old_bucket = node_buckets[old_arity];
- old_bucket_len = node_bucket_get_length(old_bucket);
- old_bucket_index = node->bucket_index;
-
- if (old_bucket_len <= old_bucket_index || old_bucket[old_bucket_index]
- != node) {
- unsigned bucket_len = node_bucket_get_length(node_buckets[arity]);
+ if (degree > 2) return;
+ if (!node_bucket_contains(node_buckets[old_degree], node)) {
/* Old arity is new arity, so we have nothing to do. */
- assert(old_bucket_index < bucket_len);
- assert(node_buckets[arity][old_bucket_index] == node);
+ assert(node_bucket_contains(node_buckets[degree], node));
return;
}
- assert(old_bucket[old_bucket_index] == node);
-
/* Delete node from old bucket... */
- node_bucket_remove(&node_buckets[old_arity], node);
+ node_bucket_remove(&node_buckets[old_degree], node);
/* ..and add to new one. */
- node->bucket_index = node_bucket_get_length(node_buckets[arity]);
- ARR_APP1(pbqp_node*, node_buckets[arity], node);
+ node_bucket_insert(&node_buckets[degree], node);
}
static void check_melting_possibility(pbqp *pbqp, pbqp_edge *edge)
}
}
-void solve_pbqp_heuristical(pbqp *pbqp)
+static void initial_simplify_edges(pbqp *pbqp)
{
unsigned node_index;
unsigned node_len;
if (!node) continue;
edges = node->edges;
- edge_len = ARR_LEN(edges);
+ edge_len = pbqp_node_get_degree(node);
for (edge_index = 0; edge_index < edge_len; ++edge_index) {
pbqp_edge *edge = edges[edge_index];
simplify_edge(pbqp, edge);
}
}
+}
- /* Put node into bucket representing their arity. */
- fill_node_buckets(pbqp);
-
- for (;;) {
- if (edge_bucket_get_length(edge_bucket) > 0) {
- apply_edge(pbqp);
- } else if (node_bucket_get_length(node_buckets[1]) > 0) {
- apply_RI(pbqp);
- } else if (node_bucket_get_length(node_buckets[2]) > 0) {
- apply_RII(pbqp);
- } else if (node_bucket_get_length(node_buckets[3]) > 0) {
- apply_RN(pbqp);
- } else {
- break;
- }
- }
+num determine_solution(FILE *file)
+{
+ unsigned node_index;
+ unsigned node_len;
+ num solution;
- if (pbqp->dump_file) {
- dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
- dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
+ if (file) {
+ dump_section(file, 1, "4. Determine Solution/Minimum");
+ dump_section(file, 2, "4.1. Trivial Solution");
}
/* Solve trivial nodes and calculate solution. */
assert(node);
node->solution = vector_get_min_index(node->costs);
- pbqp->solution = pbqp_add(pbqp->solution,
+ solution = pbqp_add(solution,
node->costs->entries[node->solution].data);
- if (pbqp->dump_file) {
- fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
- dump_node(pbqp, node);
+ if (file) {
+ fprintf(file, "node n%d is set to %d<br>\n", node->index, node->solution);
+ dump_node(file, node);
}
}
+ if (file) {
+ dump_section(file, 2, "Minimum");
+ fprintf(file, "Minimum is equal to %lld.", solution);
+ }
+
+ return solution;
+}
+
+static void back_propagate(pbqp *pbqp)
+{
+ unsigned node_index;
+ unsigned node_len = node_bucket_get_length(reduced_bucket);
+
+ assert(pbqp);
if (pbqp->dump_file) {
- dump_section(pbqp->dump_file, 2, "Minimum");
- fprintf(pbqp->dump_file, "Minimum is equal to %lld.", pbqp->solution);
dump_section(pbqp->dump_file, 2, "Back Propagation");
}
- /* Solve reduced nodes. */
- node_len = node_bucket_get_length(reduced_bucket);
for (node_index = node_len; node_index > 0; --node_index) {
pbqp_node *node = reduced_bucket[node_index - 1];
- assert(node);
- switch (ARR_LEN(node->edges)) {
+ switch (pbqp_node_get_degree(node)) {
case 1:
back_propagate_RI(pbqp, node);
break;
break;
}
}
+}
+
+static void apply_heuristic_reductions(pbqp *pbqp)
+{
+ for (;;) {
+ if (edge_bucket_get_length(edge_bucket) > 0) {
+ apply_edge(pbqp);
+ } else if (node_bucket_get_length(node_buckets[1]) > 0) {
+ apply_RI(pbqp);
+ } else if (node_bucket_get_length(node_buckets[2]) > 0) {
+ apply_RII(pbqp);
+ } else if (node_bucket_get_length(node_buckets[3]) > 0) {
+ apply_RN(pbqp);
+ } else {
+ return;
+ }
+ }
+}
+
+void solve_pbqp_heuristical(pbqp *pbqp)
+{
+ /* Reduce nodes degree ... */
+ initial_simplify_edges(pbqp);
+
+ /* ... and put node into bucket representing their degree. */
+ fill_node_buckets(pbqp);
+
+ apply_heuristic_reductions(pbqp);
+
+ pbqp->solution = determine_solution(pbqp->dump_file);
+
+ /* Solve reduced nodes. */
+ back_propagate(pbqp);
free_buckets();
}
int is_src = edge->src == node;
pbqp_node *other_node;
+ assert(pbqp_node_get_degree(node) == 1);
+
if (is_src) {
other_node = edge->tgt;
} else {
dump_section(pbqp->dump_file, 2, txt);
pbqp_dump_graph(pbqp);
fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
- dump_node(pbqp, node);
- dump_node(pbqp, other_node);
- dump_edge(pbqp, edge);
+ dump_node(pbqp->dump_file, node);
+ dump_node(pbqp->dump_file, other_node);
+ dump_edge(pbqp->dump_file, edge);
}
if (is_src) {
if (pbqp->dump_file) {
fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
- dump_node(pbqp, other_node);
+ dump_node(pbqp->dump_file, other_node);
}
reorder_node(other_node);
unsigned node_len;
assert(pbqp);
+ assert(pbqp_node_get_degree(node) == 2);
if (src_is_src) {
src_node = src_edge->tgt;
dump_section(pbqp->dump_file, 2, txt);
pbqp_dump_graph(pbqp);
fputs("<br>\nBefore reduction:<br>\n", pbqp->dump_file);
- dump_node(pbqp, src_node);
- dump_edge(pbqp, src_edge);
- dump_node(pbqp, node);
- dump_edge(pbqp, tgt_edge);
- dump_node(pbqp, tgt_node);
+ dump_node(pbqp->dump_file, src_node);
+ dump_edge(pbqp->dump_file, src_edge);
+ dump_node(pbqp->dump_file, node);
+ dump_edge(pbqp->dump_file, tgt_edge);
+ dump_node(pbqp->dump_file, tgt_node);
}
src_mat = src_edge->costs;
if (pbqp->dump_file) {
fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
- dump_edge(pbqp, edge);
+ dump_edge(pbqp->dump_file, edge);
}
/* Edge has changed so we simplify it. */
simplify_edge(pbqp, edge);
}
-void apply_RN(pbqp *pbqp)
+static void select_alternative(pbqp_node *node, unsigned selected_index)
+{
+ unsigned edge_index;
+ unsigned node_index;
+ unsigned node_len;
+ vector *node_vec;
+ unsigned max_degree = pbqp_node_get_degree(node);
+
+ assert(node);
+ node->solution = selected_index;
+ node_vec = node->costs;
+ node_len = node_vec->len;
+ assert(selected_index < node_len);
+
+ /* Set all other costs to infinity. */
+ for (node_index = 0; node_index < node_len; ++node_index) {
+ if (node_index != selected_index) {
+ node_vec->entries[node_index].data = INF_COSTS;
+ }
+ }
+
+ /* Add all incident edges to edge bucket, since they are now independent. */
+ for (edge_index = 0; edge_index < max_degree; ++edge_index) {
+ insert_into_edge_bucket(node->edges[edge_index]);
+ }
+}
+
+static pbqp_node *get_node_with_max_degree(void)
{
pbqp_node **bucket = node_buckets[3];
unsigned bucket_len = node_bucket_get_length(bucket);
unsigned bucket_index;
- pbqp_node *node = NULL;
+ unsigned max_degree = 0;
+ pbqp_node *result = NULL;
+
+ for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
+ pbqp_node *candidate = bucket[bucket_index];
+ unsigned degree = pbqp_node_get_degree(candidate);
+
+ if (degree > max_degree) {
+ result = candidate;
+ max_degree = degree;
+ }
+ }
+
+ return result;
+}
+
+static unsigned get_local_minimal_alternative(pbqp *pbqp, pbqp_node *node)
+{
pbqp_edge *edge;
vector *node_vec;
vector *vec;
int is_src;
assert(pbqp);
-
- /* Search for node with maximum degree. */
- for (bucket_index = 0; bucket_index < bucket_len; ++bucket_index) {
- pbqp_node *candidate = bucket[bucket_index];
- unsigned degree = ARR_LEN(candidate->edges);
-
- if (degree > max_degree) {
- node = candidate;
- max_degree = degree;
- }
- }
assert(node);
node_vec = node->costs;
node_len = node_vec->len;
- if (pbqp->dump_file) {
- char txt[100];
- sprintf(txt, "RN-Reduction of Node n%d", node->index);
- dump_section(pbqp->dump_file, 2, txt);
- pbqp_dump_graph(pbqp);
- }
-
for (node_index = 0; node_index < node_len; ++node_index) {
num value = node_vec->entries[node_index].data;
}
}
+ return min_index;
+}
+
+void apply_RN(pbqp *pbqp)
+{
+ pbqp_node *node = NULL;
+ unsigned min_index = 0;
+
+ assert(pbqp);
+
+ /* We want to reduce a node with maximum degree. */
+ node = get_node_with_max_degree();
+ assert(node);
+ assert(pbqp_node_get_degree(node) > 2);
+
+ if (pbqp->dump_file) {
+ char txt[100];
+ sprintf(txt, "RN-Reduction of Node n%d", node->index);
+ dump_section(pbqp->dump_file, 2, txt);
+ pbqp_dump_graph(pbqp);
+ }
+
+ min_index = get_local_minimal_alternative(pbqp, node);
+
if (pbqp->dump_file) {
fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
node->index, min_index);
- fprintf(pbqp->dump_file, "Minimal cost of RN reduction: %lld<br>\n",
- min);
}
- node->solution = min_index;
-
/* Now that we found the local minimum set all other costs to infinity. */
+ select_alternative(node, min_index);
+}
+
+static void apply_brute_force_reductions(pbqp *pbqp)
+{
+ for (;;) {
+ if (edge_bucket_get_length(edge_bucket) > 0) {
+ apply_edge(pbqp);
+ } else if (node_bucket_get_length(node_buckets[1]) > 0) {
+ apply_RI(pbqp);
+ } else if (node_bucket_get_length(node_buckets[2]) > 0) {
+ apply_RII(pbqp);
+ } else if (node_bucket_get_length(node_buckets[3]) > 0) {
+ apply_Brute_Force(pbqp);
+ } else {
+ return;
+ }
+ }
+}
+
+static unsigned get_minimal_alternative(pbqp *pbqp, pbqp_node *node)
+{
+ vector *node_vec;
+ unsigned node_index;
+ unsigned node_len;
+ unsigned min_index = 0;
+ num min = INF_COSTS;
+ unsigned bucket_index;
+
+ assert(pbqp);
+ assert(node);
+ node_vec = node->costs;
+ node_len = node_vec->len;
+ bucket_index = node->bucket_index;
+
for (node_index = 0; node_index < node_len; ++node_index) {
- if (node_index != min_index) {
- node_vec->entries[node_index].data = INF_COSTS;
+ pbqp_node_bucket bucket_deg3;
+ num value;
+ unsigned bucket_0_length;
+ unsigned bucket_red_length;
+
+ /* Some node buckets and the edge bucket should be empty. */
+ assert(node_bucket_get_length(node_buckets[1]) == 0);
+ assert(node_bucket_get_length(node_buckets[2]) == 0);
+ assert(edge_bucket_get_length(edge_bucket) == 0);
+
+ /* char *tmp = obstack_finish(&pbqp->obstack); */
+
+ /* Save current PBQP state. */
+ node_bucket_deep_copy(pbqp, &bucket_deg3, node_buckets[3]);
+ bucket_0_length = node_bucket_get_length(node_buckets[0]);
+ bucket_red_length = node_bucket_get_length(reduced_bucket);
+
+ /* Select alternative and solve PBQP recursively. */
+ select_alternative(node_buckets[3][bucket_index], node_index);
+ apply_brute_force_reductions(pbqp);
+
+ value = determine_solution(pbqp->dump_file);
+
+ if (value < min) {
+ min = value;
+ min_index = node_index;
}
+
+ /* Some node buckets and the edge bucket should still be empty. */
+ assert(node_bucket_get_length(node_buckets[1]) == 0);
+ assert(node_bucket_get_length(node_buckets[2]) == 0);
+ assert(edge_bucket_get_length(edge_bucket) == 0);
+
+ /* Clear modified buckets... */
+ node_bucket_shrink(&node_buckets[3], 0);
+
+ /* ... and restore old PBQP state. */
+ node_bucket_shrink(&node_buckets[0], bucket_0_length);
+ node_bucket_shrink(&reduced_bucket, bucket_red_length);
+ node_bucket_copy(&node_buckets[3], bucket_deg3);
+
+ /* Free copies. */
+ /* obstack_free(&pbqp->obstack, tmp); */
+ node_bucket_free(&bucket_deg3);
}
- /* Add all incident edges to edge bucket, since they are now independent. */
- for (edge_index = 0; edge_index < max_degree; ++edge_index) {
- insert_into_edge_bucket(node->edges[edge_index]);
+ return min_index;
+}
+
+void apply_Brute_Force(pbqp *pbqp)
+{
+ pbqp_node *node = NULL;
+ unsigned min_index = 0;
+
+ assert(pbqp);
+
+ /* We want to reduce a node with maximum degree. */
+ node = get_node_with_max_degree();
+ assert(node);
+ assert(pbqp_node_get_degree(node) > 2);
+
+ if (pbqp->dump_file) {
+ char txt[100];
+ sprintf(txt, "BF-Reduction of Node n%d", node->index);
+ dump_section(pbqp->dump_file, 2, txt);
+ pbqp_dump_graph(pbqp);
+ }
+
+ min_index = get_minimal_alternative(pbqp, node);
+
+ if (pbqp->dump_file) {
+ fprintf(pbqp->dump_file, "node n%d is set to %d<br><br>\n",
+ node->index, min_index);
}
+
+ /* Now that we found the minimum set all other costs to infinity. */
+ select_alternative(node, min_index);
+}
+
+void solve_pbqp_brute_force(pbqp *pbqp)
+{
+ /* Reduce nodes degree ... */
+ initial_simplify_edges(pbqp);
+
+ /* ... and put node into bucket representing their degree. */
+ fill_node_buckets(pbqp);
+
+ apply_brute_force_reductions(pbqp);
+
+ pbqp->solution = determine_solution(pbqp->dump_file);
+
+ /* Solve reduced nodes. */
+ back_propagate(pbqp);
+
+ free_buckets();
}
void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
{
if (!reduced_bucket) return 0;
- assert(node);
- if (ARR_LEN(node->edges) == 0) return 1;
+ if (pbqp_node_get_degree(node) == 0) return 1;
return node_bucket_contains(reduced_bucket, node);
}