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Extract method to build flow digraph

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master
Alinson S. Xavier 11 years ago
parent 81995ac378
commit 2a2fd6713b
1 changed files with 64 additions and 47 deletions
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111
src/gtsp.c
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@ -385,56 +385,26 @@ int GTSP_add_subtour_elimination_cut_3(
return rval;
}
int GTSP_find_exact_subtour_elimination_cuts(
struct LP *lp, struct GTSP *data, int *added_cuts_count)
int GTSP_build_flow_digraph(struct GTSP *data, double *x, struct Graph *digraph, double *capacities)
{
int rval = 0;
int *clusters = data->clusters;
double *x = 0;
double *capacities = 0;
double *flow = 0;
struct Edge **cut_edges = 0;
int *digraph_edges = 0;
struct Graph *graph = data->graph;
int node_count = graph->node_count;
int num_cols = LP_get_num_cols(lp);
x = (double *) malloc(num_cols * sizeof(double));
abort_if(!x, "could not allocate x");
rval = LP_get_x(lp, x);
abort_if(rval, "LP_get_x failed");
struct Graph digraph;
graph_init(&digraph);
int node_count = graph->node_count;
int digraph_edge_count = 4 * graph->edge_count + 2 * graph->node_count +
2 * data->cluster_count;
int digraph_node_count = node_count + data->cluster_count + 1;
digraph_edges = (int *) malloc(2 * digraph_edge_count * sizeof(int));
flow = (double *) malloc(digraph_edge_count * sizeof(double));
capacities = (double *) malloc(digraph_edge_count * sizeof(double));
cut_edges =
(struct Edge **) malloc(digraph_edge_count * sizeof(struct Edge *));
abort_if(!digraph_edges, "could not allocate digraph_edges");
abort_if(!flow, "could not allocate flow");
abort_if(!capacities, "could not allocate capacities");
abort_if(!cut_edges, "could not allocate cut_edges");
// Create four directed edges for each edge of the original graph
int ke = 0;
int kc = 0;
for (int i = 0; i < graph->edge_count; i++)
{
assert(node_count + i < num_cols);
struct Edge *e = &graph->edges[i];
int from = e->from->index;
int to = e->to->index;
@ -489,30 +459,78 @@ int GTSP_find_exact_subtour_elimination_cuts(
assert(kc == digraph_edge_count);
rval = graph_build(digraph_node_count, digraph_edge_count, digraph_edges, 1,
&digraph);
digraph);
abort_if(rval, "graph_build failed");
for (int i = 0; i < digraph_edge_count; i += 2)
{
digraph.edges[i].reverse = &digraph.edges[i + 1];
digraph.edges[i + 1].reverse = &digraph.edges[i];
digraph->edges[i].reverse = &digraph->edges[i + 1];
digraph->edges[i + 1].reverse = &digraph->edges[i];
}
int max_x_index = 0;
double max_x = DBL_MIN;
for (int i = 0; i < node_count; i++)
CLEANUP:
return rval;
}
int GTSP_find_exact_subtour_elimination_cuts(
struct LP *lp, struct GTSP *data, int *added_cuts_count)
{
int rval = 0;
double *x = 0;
double *flow = 0;
double *capacities = 0;
struct Edge **cut_edges = 0;
int *clusters = data->clusters;
struct Graph *graph = data->graph;
int node_count = graph->node_count;
int num_cols = LP_get_num_cols(lp);
x = (double *) malloc(num_cols * sizeof(double));
abort_if(!x, "could not allocate x");
rval = LP_get_x(lp, x);
abort_if(rval, "LP_get_x failed");
struct Graph digraph;
graph_init(&digraph);
int digraph_edge_count = 4 * graph->edge_count + 2 * graph->node_count +
2 * data->cluster_count;
flow = (double *) malloc(digraph_edge_count * sizeof(double));
capacities = (double *) malloc(digraph_edge_count * sizeof(double));
cut_edges =
(struct Edge **) malloc(digraph_edge_count * sizeof(struct Edge *));
abort_if(!flow, "could not allocate flow");
abort_if(!capacities, "could not allocate capacities");
abort_if(!cut_edges, "could not allocate cut_edges");
rval = GTSP_build_flow_digraph(data, x, &digraph, capacities);
abort_if(rval, "GTSP_build_flow_digraph failed");
// Constraints (2.3)
{
struct Node *n = &graph->nodes[i];
if (x[n->index] > max_x)
int max_x_index = 0;
double max_x = DBL_MIN;
for (int i = 0; i < node_count; i++)
{
max_x = x[n->index];
max_x_index = i;
struct Node *n = &graph->nodes[i];
if (x[n->index] > max_x)
{
max_x = x[n->index];
max_x_index = i;
}
}
}
// Constraints (2.3)
{
int i = max_x_index;
for (int j = 0; j < node_count; j++)
@ -681,7 +699,7 @@ int GTSP_find_exact_subtour_elimination_cuts(
}
// subcluster
struct Node *root = &digraph.nodes[digraph_node_count - 1];
struct Node *root = &digraph.nodes[digraph.node_count - 1];
for (int e_index = 0; e_index < graph->edge_count; e_index++)
{
struct Edge *e = &graph->edges[e_index];
@ -821,7 +839,6 @@ int GTSP_find_exact_subtour_elimination_cuts(
CLEANUP:
graph_free(&digraph);
if (digraph_edges) free(digraph_edges);
if (flow) free(flow);
if (cut_edges) free(cut_edges);
if (capacities) free(capacities);