#include "matrix.h"
#include "pbqp_edge.h"
#include "pbqp_edge_t.h"
+#include "pbqp_node.h"
#include "pbqp_node_t.h"
#include "vector.h"
static pbqp_edge **edge_bucket;
static pbqp_node **node_buckets[4];
+static pbqp_node **reduced_bucket = NULL;
+static int buckets_filled = 0;
+
+static void insert_into_edge_bucket(pbqp_edge *edge)
+{
+ unsigned bucket_len = ARR_LEN(edge_bucket);
+
+ if (edge->bucket_index < bucket_len && edge_bucket[edge->bucket_index]
+ == edge)
+ /* Edge is already inserted. */
+ return;
+
+ edge->bucket_index = bucket_len;
+ ARR_APP1(pbqp_edge *, edge_bucket, edge);
+}
static void init_buckets(void)
{
int i;
edge_bucket = NEW_ARR_F(pbqp_edge *, 0);
+ reduced_bucket = NEW_ARR_F(pbqp_node *, 0);
for (i = 0; i < 4; ++i) {
node_buckets[i] = NEW_ARR_F(pbqp_node *, 0);
}
}
+static void free_buckets(void)
+{
+ int i;
+
+ for (i = 0; i < 4; ++i) {
+ DEL_ARR_F(node_buckets[i]);
+ node_buckets[i] = NULL;
+ }
+
+ DEL_ARR_F(edge_bucket);
+ edge_bucket = NULL;
+
+ DEL_ARR_F(reduced_bucket);
+ reduced_bucket = NULL;
+
+ buckets_filled = 0;
+}
+
static void fill_node_buckets(pbqp *pbqp)
{
unsigned node_index;
arity = 3;
}
+ node->bucket_index = ARR_LEN(node_buckets[arity]);
+
ARR_APP1(pbqp_node *, node_buckets[arity], node);
}
+
+ buckets_filled = 1;
}
-static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
+static void normalize_towards_source(pbqp *pbqp, pbqp_edge *edge)
{
pbqp_matrix *mat;
pbqp_node *src_node;
int src_len;
int tgt_len;
int src_index;
- int tgt_index;
assert(pbqp);
assert(edge);
- if(pbqp->dump_file) {
- char txt[100];
- sprintf(txt, "Simplification of Edge n%d-n%d", edge->src, edge->tgt);
- dump_section(pbqp->dump_file, 3, txt);
- }
-
- src_node = get_node(pbqp, edge->src);
- tgt_node = get_node(pbqp, edge->tgt);
+ src_node = edge->src;
+ tgt_node = edge->tgt;
assert(src_node);
assert(tgt_node);
mat = edge->costs;
assert(mat);
- if (pbqp->dump_file) {
- fputs("Input:<br>\n", pbqp->dump_file);
- dump_simplifyedge(pbqp, edge);
- }
-
/* Normalize towards source node. */
for (src_index = 0; src_index < src_len; ++src_index) {
num min = pbqp_matrix_get_row_min(mat, src_index, tgt_vec);
if (min != 0) {
- pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
- vector_add_value(src_vec, min);
-
- // TODO add to edge_list if inf
+ if (src_vec->entries[src_index].data == INF_COSTS) {
+ pbqp_matrix_set_row_value(mat, src_index, 0);
+ } else {
+ pbqp_matrix_sub_row_value(mat, src_index, tgt_vec, min);
+ }
+ src_vec->entries[src_index].data = pbqp_add(
+ src_vec->entries[src_index].data, min);
+
+ if (min == INF_COSTS) {
+ insert_into_edge_bucket(edge);
+ }
}
}
+}
+
+static void normalize_towards_target(pbqp *pbqp, pbqp_edge *edge)
+{
+ pbqp_matrix *mat;
+ pbqp_node *src_node;
+ pbqp_node *tgt_node;
+ vector *src_vec;
+ vector *tgt_vec;
+ int src_len;
+ int tgt_len;
+ int tgt_index;
+
+ assert(pbqp);
+ assert(edge);
+
+ src_node = edge->src;
+ tgt_node = edge->tgt;
+ assert(src_node);
+ assert(tgt_node);
+
+ src_vec = src_node->costs;
+ tgt_vec = tgt_node->costs;
+ assert(src_vec);
+ assert(tgt_vec);
+
+ src_len = src_vec->len;
+ tgt_len = tgt_vec->len;
+ assert(src_len > 0);
+ assert(tgt_len > 0);
+
+ mat = edge->costs;
+ assert(mat);
- /* Normalize towards target node. */
for (tgt_index = 0; tgt_index < tgt_len; ++tgt_index) {
num min = pbqp_matrix_get_col_min(mat, tgt_index, src_vec);
if (min != 0) {
- pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
- vector_add_value(tgt_vec, min);
-
- // TODO add to edge_list if inf
+ if (tgt_vec->entries[tgt_index].data == INF_COSTS) {
+ pbqp_matrix_set_col_value(mat, tgt_index, 0);
+ } else {
+ pbqp_matrix_sub_col_value(mat, tgt_index, src_vec, min);
+ }
+ tgt_vec->entries[tgt_index].data = pbqp_add(
+ tgt_vec->entries[tgt_index].data, min);
+
+ if (min == INF_COSTS) {
+ insert_into_edge_bucket(edge);
+ }
}
}
+}
+
+static void reorder_node(pbqp_node *node)
+{
+ unsigned arity;
+ unsigned old_arity;
+ unsigned old_bucket_len;
+ unsigned old_bucket_index;
+ pbqp_node **old_bucket;
+ pbqp_node *other;
+
+ 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 = ARR_LEN(old_bucket);
+ old_bucket_index = node->bucket_index;
+
+ if (old_bucket_len <= old_bucket_index || old_bucket[old_bucket_index]
+ != node) {
+ unsigned bucket_len = ARR_LEN(node_buckets[arity]);
+
+ /* 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);
+ return;
+ }
+
+ assert(old_bucket[old_bucket_index] == node);
+
+ /* Delete node from old bucket... */
+ other = old_bucket[old_bucket_len - 1];
+ other->bucket_index = old_bucket_index;
+ old_bucket[old_bucket_index] = other;
+ ARR_SHRINKLEN(node_buckets[old_arity], old_bucket_len - 1);
+
+ /* ..and add to new one. */
+ node->bucket_index = ARR_LEN(node_buckets[arity]);
+ ARR_APP1(pbqp_node*, node_buckets[arity], node);
+}
+
+static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
+{
+ pbqp_matrix *mat;
+ pbqp_node *src_node;
+ pbqp_node *tgt_node;
+ vector *src_vec;
+ vector *tgt_vec;
+ int src_len;
+ int tgt_len;
+
+ assert(pbqp);
+ assert(edge);
+
+ src_node = edge->src;
+ tgt_node = edge->tgt;
+ assert(src_node);
+ assert(tgt_node);
+
+ /* If edge are already deleted, we have nothing to do. */
+ if (!is_connected(src_node, edge) || !is_connected(tgt_node, edge))
+ return;
+
+ if (pbqp->dump_file) {
+ char txt[100];
+ sprintf(txt, "Simplification of Edge n%d-n%d", src_node->index, tgt_node->index);
+ dump_section(pbqp->dump_file, 3, txt);
+ }
+
+ src_vec = src_node->costs;
+ tgt_vec = tgt_node->costs;
+ assert(src_vec);
+ assert(tgt_vec);
+
+ src_len = src_vec->len;
+ tgt_len = tgt_vec->len;
+ assert(src_len > 0);
+ assert(tgt_len > 0);
+
+ mat = edge->costs;
+ assert(mat);
+
+ if (pbqp->dump_file) {
+ fputs("Input:<br>\n", pbqp->dump_file);
+ dump_simplifyedge(pbqp, edge);
+ }
+
+ normalize_towards_source(pbqp, edge);
+ normalize_towards_target(pbqp, edge);
if (pbqp->dump_file) {
fputs("<br>\nOutput:<br>\n", pbqp->dump_file);
if (pbqp_matrix_is_zero(mat, src_vec, tgt_vec)) {
if (pbqp->dump_file) {
- fputs("edge has been eliminated", pbqp->dump_file);
-
- delete_edge(pbqp, edge);
+ fputs("edge has been eliminated<br>\n", pbqp->dump_file);
}
+
+ delete_edge(edge);
+ reorder_node(src_node);
+ reorder_node(tgt_node);
}
}
pbqp_edge *edge = edges[edge_index];
/* Simplify only once per edge. */
- if (node_index != edge->src) continue;
+ if (node != edge->src) continue;
simplify_edge(pbqp, edge);
}
for (;;) {
if (ARR_LEN(edge_bucket) > 0) {
- panic("Please implement edge simplification");
+ apply_edge(pbqp);
} else if (ARR_LEN(node_buckets[1]) > 0) {
- panic("Please implement RI simplification");
+ apply_RI(pbqp);
} else if (ARR_LEN(node_buckets[2]) > 0) {
- panic("Please implement RII simplification");
+ apply_RII(pbqp);
} else if (ARR_LEN(node_buckets[3]) > 0) {
- panic("Please implement RN simplification");
+ apply_RN(pbqp);
} else {
- panic("Please implement back propagation");
- // break;
+ break;
+ }
+ }
+
+ if (pbqp->dump_file) {
+ dump_section(pbqp->dump_file, 1, "4. Determine Solution/Minimum");
+ dump_section(pbqp->dump_file, 2, "4.1. Trivial Solution");
+ }
+
+ /* Solve trivial nodes and calculate solution. */
+ node_len = ARR_LEN(node_buckets[0]);
+ for (node_index = 0; node_index < node_len; ++node_index) {
+ pbqp_node *node = node_buckets[0][node_index];
+ assert(node);
+
+ node->solution = vector_get_min_index(node->costs);
+ pbqp->solution = pbqp_add(pbqp->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 (pbqp->dump_file) {
+ dump_section(pbqp->dump_file, 2, "Minimum");
+ fprintf(pbqp->dump_file, "Minimum is equal to %d.", pbqp->solution);
+ dump_section(pbqp->dump_file, 2, "Back Propagation");
+ }
+
+ /* Solve reduced nodes. */
+ node_len = ARR_LEN(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)) {
+ case 1:
+ back_propagate_RI(pbqp, node);
+ break;
+ case 2:
+ back_propagate_RII(pbqp, node);
+ break;
+ default:
+ panic("Only nodes with degree one or two should be in this bucket");
+ break;
}
}
+
+ free_buckets();
+}
+
+void apply_edge(pbqp *pbqp)
+{
+ unsigned bucket_len = ARR_LEN(edge_bucket);
+ pbqp_edge *edge = edge_bucket[bucket_len - 1];
+
+ ARR_SHRINKLEN(edge_bucket, (int)bucket_len - 1);
+
+ simplify_edge(pbqp, edge);
+}
+
+void apply_RI(pbqp *pbqp)
+{
+ pbqp_node **bucket = node_buckets[1];
+ unsigned bucket_len = ARR_LEN(bucket);
+ pbqp_node *node = bucket[bucket_len - 1];
+ pbqp_edge *edge = node->edges[0];
+ pbqp_matrix *mat = edge->costs;
+ int is_src = edge->src == node;
+ pbqp_node *other_node;
+
+ if (is_src) {
+ other_node = edge->tgt;
+ } else {
+ other_node = edge->src;
+ }
+
+ if (pbqp->dump_file) {
+ char txt[100];
+ sprintf(txt, "RI-Reduction of Node n%d", node->index);
+ 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);
+ }
+
+ if (is_src) {
+ pbqp_matrix_add_to_all_cols(mat, node->costs);
+ normalize_towards_target(pbqp, edge);
+ } else {
+ pbqp_matrix_add_to_all_rows(mat, node->costs);
+ normalize_towards_source(pbqp, edge);
+ }
+ disconnect_edge(other_node, edge);
+
+ if (pbqp->dump_file) {
+ fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
+ dump_node(pbqp, other_node);
+ }
+
+ /* Remove node from bucket... */
+ ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
+ reorder_node(other_node);
+
+ /* ...and add it to back propagation list. */
+ node->bucket_index = ARR_LEN(reduced_bucket);
+ ARR_APP1(pbqp_node *, reduced_bucket, node);
+}
+
+void apply_RII(pbqp *pbqp)
+{
+ pbqp_node **bucket = node_buckets[2];
+ unsigned bucket_len = ARR_LEN(bucket);
+ pbqp_node *node = bucket[bucket_len - 1];
+ pbqp_edge *src_edge = node->edges[0];
+ pbqp_edge *tgt_edge = node->edges[1];
+ int src_is_src = src_edge->src == node;
+ int tgt_is_src = tgt_edge->src == node;
+ pbqp_matrix *src_mat;
+ pbqp_matrix *tgt_mat;
+ pbqp_node *src_node;
+ pbqp_node *tgt_node;
+ pbqp_matrix *mat;
+ vector *vec;
+ vector *node_vec;
+ vector *src_vec;
+ vector *tgt_vec;
+ unsigned col_index;
+ unsigned col_len;
+ unsigned row_index;
+ unsigned row_len;
+ unsigned node_len;
+
+ assert(pbqp);
+
+ if (src_is_src) {
+ src_node = src_edge->tgt;
+ } else {
+ src_node = src_edge->src;
+ }
+
+ if (tgt_is_src) {
+ tgt_node = tgt_edge->tgt;
+ } else {
+ tgt_node = tgt_edge->src;
+ }
+
+ /* Swap nodes if necessary. */
+ if (tgt_node->index < src_node->index) {
+ pbqp_node *tmp_node;
+ pbqp_edge *tmp_edge;
+
+ tmp_node = src_node;
+ src_node = tgt_node;
+ tgt_node = tmp_node;
+
+ tmp_edge = src_edge;
+ src_edge = tgt_edge;
+ tgt_edge = tmp_edge;
+
+ src_is_src = src_edge->src == node;
+ tgt_is_src = tgt_edge->src == node;
+ }
+
+ if (pbqp->dump_file) {
+ char txt[100];
+ sprintf(txt, "RII-Reduction of Node n%d", node->index);
+ 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);
+ }
+
+ src_mat = src_edge->costs;
+ tgt_mat = tgt_edge->costs;
+
+ src_vec = src_node->costs;
+ tgt_vec = tgt_node->costs;
+ node_vec = node->costs;
+
+ row_len = src_vec->len;
+ col_len = tgt_vec->len;
+ node_len = node_vec->len;
+
+ mat = pbqp_matrix_alloc(pbqp, row_len, col_len);
+
+ for (row_index = 0; row_index < row_len; ++row_index) {
+ for (col_index = 0; col_index < col_len; ++col_index) {
+ vec = vector_copy(pbqp, node_vec);
+
+ if (src_is_src) {
+ vector_add_matrix_col(vec, src_mat, row_index);
+ } else {
+ vector_add_matrix_row(vec, src_mat, row_index);
+ }
+
+ if (tgt_is_src) {
+ vector_add_matrix_col(vec, tgt_mat, col_index);
+ } else {
+ vector_add_matrix_row(vec, tgt_mat, col_index);
+ }
+
+ mat->entries[row_index * col_len + col_index] = vector_get_min(vec);
+
+ obstack_free(&pbqp->obstack, vec);
+ }
+ }
+
+ pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
+
+ /* Disconnect node. */
+ disconnect_edge(src_node, src_edge);
+ disconnect_edge(tgt_node, tgt_edge);
+
+ /* Remove node from bucket... */
+ ARR_SHRINKLEN(bucket, (int)bucket_len - 1);
+
+ /* ...and add it to back propagation list. */
+ node->bucket_index = ARR_LEN(reduced_bucket);
+ ARR_APP1(pbqp_node *, reduced_bucket, node);
+
+ if (edge == NULL) {
+ edge = alloc_edge(pbqp, src_node->index, tgt_node->index, mat);
+ } else {
+ pbqp_matrix_add(edge->costs, mat);
+
+ /* Free local matrix. */
+ obstack_free(&pbqp->obstack, mat);
+
+ reorder_node(src_node);
+ reorder_node(tgt_node);
+ }
+
+ if (pbqp->dump_file) {
+ fputs("<br>\nAfter reduction:<br>\n", pbqp->dump_file);
+ dump_edge(pbqp, edge);
+ }
+
+ /* Edge has changed so we simplify it. */
+ simplify_edge(pbqp, edge);
+}
+
+void apply_RN(pbqp *pbqp)
+{
+ pbqp_node **bucket = node_buckets[3];
+ unsigned bucket_len = ARR_LEN(bucket);
+ pbqp_node *node = bucket[bucket_len - 1];
+ pbqp_edge *edge;
+ vector *node_vec = node->costs;
+ vector *vec;
+ pbqp_matrix *mat;
+ unsigned edge_index;
+ unsigned edge_len = ARR_LEN(node->edges);
+ unsigned node_index;
+ unsigned node_len = node_vec->len;
+ unsigned min_index = 0;
+ num min = INF_COSTS;
+ int is_src;
+
+ assert(pbqp);
+
+ 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 = 0;
+
+ for (edge_index = 0; edge_index < edge_len; ++edge_index) {
+ edge = node->edges[edge_index];
+ mat = edge->costs;
+ is_src = edge->src == node;
+
+ if (is_src) {
+ vec = vector_copy(pbqp, edge->tgt->costs);
+ vector_add_matrix_row(vec, mat, node_index);
+ } else {
+ vec = vector_copy(pbqp, edge->src->costs);
+ vector_add_matrix_col(vec, mat, node_index);
+ }
+
+ value = pbqp_add(value, vector_get_min(vec));
+
+ obstack_free(&pbqp->obstack, vec);
+ }
+
+ if (value < min) {
+ min = value;
+ min_index = node_index;
+ }
+ }
+
+ 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: %d<br>\n",
+ min);
+ }
+
+ node->solution = min_index;
+
+ /* Now that we found the local minimum set all other costs to infinity. */
+ for (node_index = 0; node_index < node_len; ++node_index) {
+ if (node_index != min_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 < edge_len; ++edge_index) {
+ insert_into_edge_bucket(node->edges[edge_index]);
+ }
+}
+
+void back_propagate_RI(pbqp *pbqp, pbqp_node *node)
+{
+ pbqp_edge *edge;
+ pbqp_node *other;
+ pbqp_matrix *mat;
+ vector *vec;
+ int is_src;
+
+ assert(pbqp);
+ assert(node);
+
+ edge = node->edges[0];
+ mat = edge->costs;
+ is_src = edge->src == node;
+ vec = node->costs;
+
+ if (is_src) {
+ other = edge->tgt;
+ assert(other);
+ vector_add_matrix_col(vec, mat, other->solution);
+ } else {
+ other = edge->src;
+ assert(other);
+ vector_add_matrix_row(vec, mat, other->solution);
+ }
+
+ node->solution = vector_get_min_index(vec);
+ if (pbqp->dump_file) {
+ fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
+ }
+}
+
+void back_propagate_RII(pbqp *pbqp, pbqp_node *node)
+{
+ pbqp_edge *src_edge = node->edges[0];
+ pbqp_edge *tgt_edge = node->edges[1];
+ int src_is_src = src_edge->src == node;
+ int tgt_is_src = tgt_edge->src == node;
+ pbqp_matrix *src_mat;
+ pbqp_matrix *tgt_mat;
+ pbqp_node *src_node;
+ pbqp_node *tgt_node;
+ vector *vec;
+ vector *node_vec;
+ unsigned col_index;
+ unsigned row_index;
+
+ assert(pbqp);
+
+ if (src_is_src) {
+ src_node = src_edge->tgt;
+ } else {
+ src_node = src_edge->src;
+ }
+
+ if (tgt_is_src) {
+ tgt_node = tgt_edge->tgt;
+ } else {
+ tgt_node = tgt_edge->src;
+ }
+
+ /* Swap nodes if necessary. */
+ if (tgt_node->index < src_node->index) {
+ pbqp_node *tmp_node;
+ pbqp_edge *tmp_edge;
+
+ tmp_node = src_node;
+ src_node = tgt_node;
+ tgt_node = tmp_node;
+
+ tmp_edge = src_edge;
+ src_edge = tgt_edge;
+ tgt_edge = tmp_edge;
+
+ src_is_src = src_edge->src == node;
+ tgt_is_src = tgt_edge->src == node;
+ }
+
+ src_mat = src_edge->costs;
+ tgt_mat = tgt_edge->costs;
+
+ node_vec = node->costs;
+
+ row_index = src_node->solution;
+ col_index = tgt_node->solution;
+
+ vec = vector_copy(pbqp, node_vec);
+
+ if (src_is_src) {
+ vector_add_matrix_col(vec, src_mat, row_index);
+ } else {
+ vector_add_matrix_row(vec, src_mat, row_index);
+ }
+
+ if (tgt_is_src) {
+ vector_add_matrix_col(vec, tgt_mat, col_index);
+ } else {
+ vector_add_matrix_row(vec, tgt_mat, col_index);
+ }
+
+ node->solution = vector_get_min_index(vec);
+ if (pbqp->dump_file) {
+ fprintf(pbqp->dump_file, "node n%d is set to %d<br>\n", node->index, node->solution);
+ }
+
+ obstack_free(&pbqp->obstack, vec);
+}
+
+int node_is_reduced(pbqp_node *node)
+{
+ if (!reduced_bucket) return 0;
+
+ assert(node);
+ if (ARR_LEN(node->edges) == 0) return 1;
+
+ unsigned bucket_length = ARR_LEN(reduced_bucket);
+ unsigned bucket_index = node->bucket_index;
+
+ return bucket_index < bucket_length && reduced_bucket[bucket_index] == node;
}