Maybe implemented BF solver (don't tested yet).
[libfirm] / heuristical.c
index a2ec4c6..23d0488 100644 (file)
@@ -18,6 +18,9 @@ static pbqp_node **node_buckets[4];
 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)) {
@@ -428,15 +431,15 @@ static void initial_simplify_edges(pbqp *pbqp)
        }
 }
 
-num determine_solution(pbqp *pbqp)
+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. */
@@ -448,50 +451,30 @@ num determine_solution(pbqp *pbqp)
                node->solution = vector_get_min_index(node->costs);
                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;
 }
 
-void solve_pbqp_heuristical(pbqp *pbqp)
+static void back_propagate(pbqp *pbqp)
 {
        unsigned node_index;
-       unsigned node_len;
-
-       /* Reduce nodes degree ... */
-       initial_simplify_edges(pbqp);
-
-       /* ... and put node into bucket representing their degree. */
-       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;
-               }
-       }
-
-       pbqp->solution = determine_solution(pbqp);
+       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];
 
@@ -507,6 +490,39 @@ void solve_pbqp_heuristical(pbqp *pbqp)
                                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();
 }
@@ -538,9 +554,9 @@ void apply_RI(pbqp *pbqp)
                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) {
@@ -554,7 +570,7 @@ void apply_RI(pbqp *pbqp)
 
        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);
@@ -622,11 +638,11 @@ void apply_RII(pbqp *pbqp)
                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;
@@ -687,19 +703,63 @@ void apply_RII(pbqp *pbqp)
 
        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(selected_index < max_degree);
+       assert(node);
+       node->solution = selected_index;
+       node_vec = node->costs;
+       node_len = node_vec->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;
@@ -713,28 +773,10 @@ void apply_RN(pbqp *pbqp)
        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    = pbqp_node_get_degree(candidate);
-
-               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;
 
@@ -762,101 +804,161 @@ void apply_RN(pbqp *pbqp)
                }
        }
 
+       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);
+
+       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. */
-       for (node_index = 0; node_index < node_len; ++node_index) {
-               if (node_index != min_index) {
-                       node_vec->entries[node_index].data = INF_COSTS;
-               }
-       }
+       select_alternative(node, min_index);
+}
 
-       /* 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 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;
+               }
        }
 }
 
-void apply_Brute_Force(pbqp *pbqp)
+static unsigned get_minimal_alternative(pbqp *pbqp, pbqp_node *node)
 {
-       pbqp_node  **bucket       = node_buckets[3];
-       unsigned     bucket_len   = node_bucket_get_length(bucket);
-       unsigned     bucket_index;
-       pbqp_node   *node         = NULL;
-       pbqp_edge   *edge;
        vector      *node_vec;
-       vector      *vec;
-       pbqp_matrix *mat;
-       unsigned     edge_index;
-       unsigned     max_degree   = 0;
        unsigned     node_index;
        unsigned     node_len;
        unsigned     min_index    = 0;
        num          min          = INF_COSTS;
-       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    = pbqp_node_get_degree(candidate);
-
-               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;
+               num value;
+
+               /* 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);
+
+               /* Save current PBQP state. */
+               pbqp_node_bucket *bucket_deg0 = node_bucket_deep_copy(node_buckets[0]);
+               pbqp_node_bucket *bucket_deg3 = node_bucket_deep_copy(node_buckets[3]);
+               pbqp_node_bucket *bucket_red  = node_bucket_deep_copy(reduced_bucket);
 
-               /* TODO Copy PBQP */
+               /* Select alternative and solve PBQP recursively. */
+               select_alternative(node, 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_clear(&node_buckets[0]);
+               node_bucket_clear(&node_buckets[3]);
+               node_bucket_clear(&reduced_bucket);
+
+               /* ... and restore old PBQP state. */
+               node_bucket_copy(&node_buckets[0], bucket_deg0);
+               node_bucket_copy(&node_buckets[3], bucket_deg3);
+               node_bucket_copy(&reduced_bucket, bucket_red);
+
+               /* Free copies. */
+               node_bucket_free(bucket_deg0);
+               node_bucket_free(bucket_deg3);
+               node_bucket_free(bucket_red);
+       }
+
+       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);
+
+       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);
-               fprintf(pbqp->dump_file, "Minimal cost of RN reduction: %lld<br>\n",
-                                                       min);
        }
 
-       node->solution = min_index;
+       /* Now that we found the minimum set all other costs to infinity. */
+       select_alternative(node, 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;
-               }
-       }
+void solve_pbqp_brute_force(pbqp *pbqp)
+{
+       /* Reduce nodes degree ... */
+       initial_simplify_edges(pbqp);
 
-       /* 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]);
-       }
+       /* ... 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)