Do not fetch a node index if we have a perfectly fine pointer already at hand.
[libfirm] / heuristical.c
index 844c87a..7605ffb 100644 (file)
@@ -8,17 +8,28 @@
 #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 num add(num x, num y)
+{
+       if (x == INF_COSTS || y == INF_COSTS) return INF_COSTS;
+
+       return x + y;
+}
 
 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);
@@ -46,11 +57,15 @@ static void fill_node_buckets(pbqp *pbqp)
                        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;
@@ -60,19 +75,12 @@ static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
        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);
 
@@ -89,34 +97,148 @@ static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
        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);
+                       src_vec->entries[src_index].data = add(
+                                       src_vec->entries[src_index].data, min);
 
                        // TODO add to edge_list if inf
                }
        }
+}
+
+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);
+                       tgt_vec->entries[tgt_index].data = add(
+                                       tgt_vec->entries[tgt_index].data, min);
 
                        // TODO add to edge_list if inf
                }
        }
+}
+
+static void reorder_node(pbqp_node *node)
+{
+       unsigned arity;
+       unsigned old_arity;
+       unsigned old_bucket_len;
+
+       if (!buckets_filled) return;
+
+       assert(node);
+
+       arity = ARR_LEN(node->edges);
+
+       /* Equal bucket as before */
+       if (arity > 2) return;
+
+       /* Assume node lost one incident edge. */
+       old_arity = arity + 1;
+
+       if (ARR_LEN(node_buckets[old_arity]) <= (int)node->bucket_index
+                       || node_buckets[old_arity][node->bucket_index] != node) {
+               /* Old arity is new arity, so we have nothing to do. */
+               return;
+       }
+
+       old_bucket_len = ARR_LEN(node_buckets[old_arity]);
+       assert (node_buckets[old_arity][node->bucket_index] == node);
+
+       /* Delete node from old bucket... */
+       node_buckets[old_arity][old_bucket_len - 1]->bucket_index
+                       = node->bucket_index;
+       node_buckets[old_arity][node->bucket_index]
+                       = node_buckets[old_arity][old_bucket_len - 1];
+       ARR_SHRINKLEN(node_buckets[old_arity], (int)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(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);
@@ -127,7 +249,9 @@ static void simplify_edge(pbqp *pbqp, pbqp_edge *edge)
                if (pbqp->dump_file) {
                        fputs("edge has been eliminated", pbqp->dump_file);
 
-                       delete_edge(pbqp, edge);
+                       delete_edge(edge);
+                       reorder_node(src_node);
+                       reorder_node(tgt_node);
                }
        }
 }
@@ -164,7 +288,7 @@ void solve_pbqp_heuristical(pbqp *pbqp)
                        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);
                }
@@ -177,14 +301,258 @@ void solve_pbqp_heuristical(pbqp *pbqp)
                if (ARR_LEN(edge_bucket) > 0) {
                        panic("Please implement edge simplification");
                } else if (ARR_LEN(node_buckets[1]) > 0) {
-                       panic("Please implement RI simplification");
+                       applyRI(pbqp);
                } else if (ARR_LEN(node_buckets[2]) > 0) {
                        panic("Please implement RII simplification");
                } else if (ARR_LEN(node_buckets[3]) > 0) {
                        panic("Please implement RN simplification");
                } 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 = 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:
+                               panic("Please implement back propagation for RII");
+                               break;
+                       default:
+                               panic("Only nodes with degree one or two should be in this bucket");
+                               break;
+               }
+       }
+}
+
+void applyRI(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-Reduktion 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 applyRII(pbqp *pbqp)
+{
+       pbqp_node  **bucket     = node_buckets[1];
+       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;
+
+       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;
+
+       src_vec  = src_node->costs;
+       tgt_vec  = tgt_node->costs;
+       node_vec = node->costs;
+
+       row_len  = ARR_LEN(src_vec);
+       col_len  = ARR_LEN(tgt_vec);
+       node_len = ARR_LEN(node_vec);
+
+       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_index(vec);
+               }
+       }
+
+       pbqp_edge *edge = get_edge(pbqp, src_node->index, tgt_node->index);
+
+       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);
+       }
+
+       /* Disconnect node. */
+       disconnect_edge(src_node, src_edge);
+       disconnect_edge(tgt_node, tgt_edge);
+
+       /* Edge has changed so we simplify it. */
+       simplify_edge(pbqp, edge);
+}
+
+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);
+       }
+}
+
+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;
 }