isoron
/
gtsp
Archived
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix cut edges mapping and cluster node activation

Browse Source
master
Alinson S. Xavier 11 years ago
parent 64351aae34
commit 55c4485137
3 changed files with 160 additions and 91 deletions
Show Stats Download Patch File Download Diff File

4
src/branch_and_cut.c
Unescape View File

@ -117,7 +117,7 @@ static int BNC_solve_node(struct BNC *bnc, int depth)
if (bnc->problem_add_cutting_planes)
{
// log_info("Adding problem cutting planes...\n");
log_debug("Adding problem cutting planes...\n");
rval = bnc->problem_add_cutting_planes(lp, bnc->problem_data);
abort_if(rval, "problem_add_cutting_planes failed");
}
@ -200,7 +200,7 @@ static int BNC_branch_node(struct BNC *bnc, double *x, int depth)
static int BNC_is_integral(double *x, int num_cols)
{
// return 1;
return 1;
for (int i = 0; i < num_cols; i++)
if (x[i] > LP_EPSILON && x[i] < 1.0 - LP_EPSILON)

243
src/gtsp.c
Unescape View File

@ -232,13 +232,14 @@ static int add_subcluster_cut(
return rval;
}
static int add_subtour_elimination_cut(
static int add_subtour_cut(
struct LP *lp,
struct Graph *graph,
struct Node *from,
struct Node *to,
struct Edge **cut_edges,
int cut_edges_count, int type)
int cut_edges_count,
int type)
{
int rval = 0;
@ -262,13 +263,13 @@ static int add_subtour_elimination_cut(
rmatval[i] = 1.0;
}
if(type >= 1)
if (type >= 1)
{
rmatind[cut_edges_count] = from->index;
rmatval[cut_edges_count] = -2.0;
}
if(type >= 2)
if (type >= 2)
{
rmatind[cut_edges_count + 1] = to->index;
rmatval[cut_edges_count + 1] = -2.0;
@ -297,7 +298,11 @@ static int add_subtour_elimination_cut(
}
static int build_flow_digraph(
struct GTSP *data, double *x, struct Graph *digraph, double *capacities)
struct GTSP *data,
double *x,
struct Graph *digraph,
double *capacities,
struct Edge **edge_map)
{
int rval = 0;
@ -324,18 +329,22 @@ static int build_flow_digraph(
digraph_edges[ke++] = from;
digraph_edges[ke++] = to;
edge_map[kc] = e;
capacities[kc++] = x[node_count + i];
digraph_edges[ke++] = to;
digraph_edges[ke++] = from;
edge_map[kc] = e;
capacities[kc++] = 0;
digraph_edges[ke++] = to;
digraph_edges[ke++] = from;
edge_map[kc] = e;
capacities[kc++] = x[node_count + i];
digraph_edges[ke++] = from;
digraph_edges[ke++] = to;
edge_map[kc] = e;
capacities[kc++] = 0;
}
@ -348,11 +357,13 @@ static int build_flow_digraph(
digraph_edges[ke++] = n->index;
digraph_edges[ke++] = node_count + cl;
capacities[kc++] = 1e10;
edge_map[kc] = 0;
capacities[kc++] = 0;
digraph_edges[ke++] = node_count + cl;
digraph_edges[ke++] = n->index;
capacities[kc++] = 1e10;
edge_map[kc] = 0;
capacities[kc++] = 0;
}
// Create an extra node and connect it to each cluster node through
@ -361,10 +372,12 @@ static int build_flow_digraph(
{
digraph_edges[ke++] = node_count + i;
digraph_edges[ke++] = node_count + data->cluster_count;
edge_map[kc] = 0;
capacities[kc++] = 0;
digraph_edges[ke++] = node_count + data->cluster_count;
digraph_edges[ke++] = node_count + i;
edge_map[kc] = 0;
capacities[kc++] = 0;
}
@ -387,33 +400,62 @@ static int build_flow_digraph(
}
static int map_cut_edges_from_digraph_to_graph(
struct Graph *graph, int *cut_edges_count, struct Edge **cut_edges)
struct Graph *graph,
struct Edge **edge_map,
int *cut_edges_count,
struct Edge **cut_edges)
{
int c = 0;
for (int k = 0; k < *cut_edges_count / 2; k++)
{
int idx = cut_edges[k * 2]->index / 4;
if (idx > graph->edge_count) continue;
int count = 0;
cut_edges[c++] = &graph->edges[idx];
for (int i = 0; i < (*cut_edges_count); i += 2)
{
struct Edge *e = edge_map[cut_edges[i]->index];
if (!e) continue;
cut_edges[count++] = e;
}
*cut_edges_count = c;
(*cut_edges_count) = count;
return 0;
}
int find_exact_subtour_elimination_cuts_0(
void deactivate_cluster_node(double *capacities, struct Node *cluster_node)
{
for (int i = 0; i < cluster_node->degree; i++)
{
struct Adjacency *adj = &cluster_node->adj[i];
struct Edge *e = adj->edge;
capacities[e->index] = 0;
}
}
void activate_cluster_node(double *capacities, struct Node *cluster_node)
{
for (int i = 0; i < cluster_node->degree; i++)
{
struct Adjacency *adj = &cluster_node->adj[i];
struct Edge *e = adj->edge;
capacities[e->index] = 1e10;
capacities[e->reverse->index] = 1e10;
}
}
int find_exact_subtour_cuts_cluster_to_cluster(
struct LP *lp,
struct GTSP *data,
struct Graph *digraph,
double *capacities,
struct Edge **edge_map,
int *added_cuts_count)
{
int rval = 0;
struct Edge **cut_edges = 0;
double *flow = 0;
struct Edge **cut_edges = 0;
int cuts_count = 0;
struct Graph *graph = data->graph;
@ -423,6 +465,9 @@ int find_exact_subtour_elimination_cuts_0(
abort_if(!cut_edges, "could not allocate cut_edges");
abort_if(!flow, "could not allocate flow");
struct Node *root_node = &digraph->nodes[graph->node_count +
data->cluster_count];
for (int i = 0; i < data->cluster_count; i++)
{
for (int j = i + 1; j < data->cluster_count; j++)
@ -433,25 +478,39 @@ int find_exact_subtour_elimination_cuts_0(
double flow_value;
int cut_edges_count;
activate_cluster_node(capacities, from);
activate_cluster_node(capacities, to);
deactivate_cluster_node(capacities, root_node);
log_verbose("Sending flow from cluster %d to cluster %d\n", i, j);
rval = flow_find_max_flow(digraph, capacities, from, to, flow,
&flow_value);
abort_if(rval, "flow_find_max_flow failed");
log_verbose(" flow value = %.4lf\n", flow_value);
deactivate_cluster_node(capacities, from);
deactivate_cluster_node(capacities, to);
if (flow_value >= 2 - LP_EPSILON) continue;
// log_debug("Flow from cluster %d to %d is insufficient\n", i, j);
rval = get_cut_edges_from_marks(digraph, &cut_edges_count,
cut_edges);
abort_if(rval, "get_cut_edges_from_marks failed");
rval = map_cut_edges_from_digraph_to_graph(graph, &cut_edges_count,
cut_edges);
rval = map_cut_edges_from_digraph_to_graph(graph, edge_map,
&cut_edges_count, cut_edges);
abort_if(rval, "map_cut_edges_from_digraph_to_graph failed");
rval = add_subtour_elimination_cut(lp, graph, 0, 0, cut_edges,
cut_edges_count, 0);
abort_if(rval, "GTSP_add_subtour_elimination_cut3 failed");
rval = add_subtour_cut(lp, graph, 0, 0, cut_edges, cut_edges_count,
0);
abort_if(rval, "add_subtour_cut failed");
(*added_cuts_count)++;
cuts_count++;
}
}
@ -461,16 +520,18 @@ int find_exact_subtour_elimination_cuts_0(
return rval;
}
int find_exact_subtour_elimination_cuts_1(
int find_exact_subtour_cuts_node_to_cluster(
struct LP *lp,
struct GTSP *data,
double *x,
struct Graph *digraph,
double *capacities,
struct Edge **edge_map,
int *added_cuts_count)
{
int rval = 0;
int cuts_count = 0;
struct Edge **cut_edges = 0;
double *flow = 0;
@ -493,6 +554,10 @@ int find_exact_subtour_elimination_cuts_1(
struct Node *from = &digraph->nodes[i];
struct Node *to = &digraph->nodes[graph->node_count + j];
log_verbose("Sending flow from %d to cluster %d\n", i, j);
activate_cluster_node(capacities, to);
double flow_value;
int cut_edges_count;
@ -500,6 +565,10 @@ int find_exact_subtour_elimination_cuts_1(
&flow_value);
abort_if(rval, "flow_find_max_flow failed");
log_verbose(" flow value = %.4lf\n", flow_value);
deactivate_cluster_node(capacities, to);
if (flow_value >= 2 * x[i] - LP_EPSILON)
continue;
@ -507,15 +576,16 @@ int find_exact_subtour_elimination_cuts_1(
cut_edges);
abort_if(rval, "get_cut_edges_from_marks failed");
rval = map_cut_edges_from_digraph_to_graph(graph, &cut_edges_count,
cut_edges);
rval = map_cut_edges_from_digraph_to_graph(graph, edge_map,
&cut_edges_count, cut_edges);
abort_if(rval, "map_cut_edges_from_digraph_to_graph failed");
rval = add_subtour_elimination_cut(lp, graph, from, 0, cut_edges,
rval = add_subtour_cut(lp, graph, from, 0, cut_edges,
cut_edges_count, 1);
abort_if(rval, "GTSP_add_subtour_elimination_cut_1 failed");
abort_if(rval, "add_subtour_cut failed");
(*added_cuts_count)++;
cuts_count++;
}
}
@ -525,12 +595,13 @@ int find_exact_subtour_elimination_cuts_1(
return rval;
}
int find_exact_subtour_elimination_cuts_2(
int find_exact_subtour_cuts_node_to_node(
struct LP *lp,
struct GTSP *data,
double *x,
struct Graph *digraph,
double *capacities,
struct Edge **edge_map,
int *added_cuts_count)
{
int rval = 0;
@ -585,15 +656,16 @@ int find_exact_subtour_elimination_cuts_2(
rval = get_cut_edges_from_marks(digraph, &cut_edges_count, cut_edges);
abort_if(rval, "get_cut_edges_from_marks failed");
rval = map_cut_edges_from_digraph_to_graph(graph, &cut_edges_count,
cut_edges);
rval = map_cut_edges_from_digraph_to_graph(graph, edge_map,
&cut_edges_count, cut_edges);
abort_if(rval, "map_cut_edges_from_digraph_to_graph failed");
rval = add_subtour_elimination_cut(lp, graph, from, to, cut_edges,
cut_edges_count, 2);
abort_if(rval, "GTSP_add_subtour_elimination_cut_1 failed");
rval = add_subtour_cut(lp, graph, from, to, cut_edges, cut_edges_count,
2);
abort_if(rval, "add_subtour_cut failed");
(*added_cuts_count)++;
goto CLEANUP;
}
CLEANUP:
@ -602,14 +674,16 @@ int find_exact_subtour_elimination_cuts_2(
return rval;
}
int find_exact_subtour_elimination_cuts(
struct LP *lp, struct GTSP *data, int *added_cuts_count)
int find_exact_subtour_cuts(
struct LP *lp, struct GTSP *data, int *total_added_cuts)
{
int rval = 0;
double *x = 0;
double *capacities = 0;
struct Edge **edge_map = 0;
int added_cuts_count = 0;
struct Graph *graph = data->graph;
int num_cols = LP_get_num_cols(lp);
@ -619,33 +693,50 @@ int find_exact_subtour_elimination_cuts(
rval = LP_get_x(lp, x);
abort_if(rval, "LP_get_x failed");
log_debug("Writing fractional solution to gtsp-frac.out\n");
rval = GTSP_write_solution(data, "gtsp-frac.out", x);
abort_if(rval, "GTSP_write_solution failed");
struct Graph digraph;
graph_init(&digraph);
int digraph_edge_count = 4 * graph->edge_count + 2 * graph->node_count +
2 * data->cluster_count;
edge_map = (struct Edge **) malloc(
digraph_edge_count * sizeof(struct Edge *));
capacities = (double *) malloc(digraph_edge_count * sizeof(double));
abort_if(!edge_map, "could not allocate edge_map");
abort_if(!capacities, "could not allocate capacities");
rval = build_flow_digraph(data, x, &digraph, capacities);
rval = build_flow_digraph(data, x, &digraph, capacities, edge_map);
abort_if(rval, "build_flow_digraph failed");
// Constraints (2.3)
rval = find_exact_subtour_elimination_cuts_2(lp, data, x, &digraph,
capacities, added_cuts_count);
abort_if(rval, "find_exact_subtour_elimination_cuts_2 failed");
// Constraints (2.1)
rval = find_exact_subtour_cuts_cluster_to_cluster(lp, data, &digraph,
capacities, edge_map, &added_cuts_count);
abort_if(rval, "find_exact_subtour_cuts_cluster_to_cluster failed");
log_debug("Added %d cluster-to-cluster subtour cuts\n", added_cuts_count);
(*total_added_cuts) += added_cuts_count;
if (added_cuts_count > 0) goto CLEANUP;
// Constraints (2.2)
rval = find_exact_subtour_elimination_cuts_1(lp, data, x, &digraph,
capacities, added_cuts_count);
abort_if(rval, "find_exact_subtour_elimination_cuts_1 failed");
rval = find_exact_subtour_cuts_node_to_cluster(lp, data, x, &digraph,
capacities, edge_map, &added_cuts_count);
abort_if(rval, "find_exact_subtour_cuts_node_to_cluster failed");
log_debug("Added %d node-to-cluster subtour cuts\n", added_cuts_count);
(*total_added_cuts) += added_cuts_count;
// Constraints (2.1)
rval = find_exact_subtour_elimination_cuts_0(lp, data, &digraph, capacities,
added_cuts_count);
abort_if(rval, "find_exact_subtour_elimination_cuts_0 failed");
// Constraints (2.3)
rval = find_exact_subtour_cuts_node_to_node(lp, data, x, &digraph,
capacities, edge_map, &added_cuts_count);
abort_if(rval, "find_exact_subtour_cuts_node_to_node failed");
log_debug("Added %d node-to-node subtour cuts\n", added_cuts_count);
(*total_added_cuts) += added_cuts_count;
// // subcluster
// struct Node *root = &digraph.nodes[digraph.node_count - 1];
@ -723,8 +814,8 @@ int find_exact_subtour_elimination_cuts(
// rval = add_subcluster_cut(lp, graph, e, cut_edges, c);
// abort_if(rval, "add_subcluster_cut failed");
//
// (*added_cuts_count)++;
// if (*added_cuts_count > 10) goto CLEANUP;
// (*total_added_cuts)++;
// if (*total_added_cuts > 10) goto CLEANUP;
//
// } else
// {
@ -763,8 +854,8 @@ int find_exact_subtour_elimination_cuts(
// rval = add_subcluster_cut(lp, graph, e, cut_edges, c);
// abort_if(rval, "add_subcluster_cut failed");
//
// (*added_cuts_count)++;
// if (*added_cuts_count > 10) goto CLEANUP;
// (*total_added_cuts)++;
// if (*total_added_cuts > 10) goto CLEANUP;
// }
// }
//
@ -788,6 +879,7 @@ int find_exact_subtour_elimination_cuts(
CLEANUP:
graph_free(&digraph);
if (edge_map) free(edge_map);
if (capacities) free(capacities);
if (x) free(x);
return rval;
@ -796,61 +888,38 @@ int find_exact_subtour_elimination_cuts(
int GTSP_add_cutting_planes(struct LP *lp, struct GTSP *data)
{
int rval = 0;
double *x = 0;
int num_cols = LP_get_num_cols(lp);
x = (double *) malloc(num_cols * sizeof(double));
abort_if(!x, "could not allocate x");
int round = 0;
int added_cuts_count = 0;
while (1)
{
int added_cuts_count = 0;
round++;
int added_cuts_this_round = 0;
log_debug("Finding subtour cuts...\n");
log_debug("Finding subtour cuts, round %d...\n", round);
rval = find_exact_subtour_elimination_cuts(lp, data, &added_cuts_count);
abort_if(rval, "find_exact_subtour_elimination_cuts failed");
rval = find_exact_subtour_cuts(lp, data, &added_cuts_this_round);
abort_if(rval, "find_exact_subtour_cuts failed");
if (added_cuts_count > 0)
if (added_cuts_this_round == 0)
{
log_debug("Found %d subtour elimination cuts using exact "
"separation\n", added_cuts_count);
} else break;
log_debug("No more subtour cuts found.\n");
break;
}
log_debug("Reoptimizing...\n");
int is_infeasible;
rval = LP_optimize(lp, &is_infeasible);
abort_if(rval, "LP_optimize failed");
if (is_infeasible) break;
double objval;
rval = LP_get_obj_val(lp, &objval);
abort_if(rval, "LP_get_obj_val failed");
rval = LP_get_x(lp, x);
abort_if(rval, "LP_get_x failed");
log_debug("Current solution:\n");
for (int i = 0; i < data->graph->node_count; i++)
if (x[i] > LP_EPSILON) log_debug(" node %d = %.2f\n", i, x[i]);
for (int i = 0; i < data->graph->edge_count; i++)
{
struct Edge *e = &data->graph->edges[i];
int idx = e->index + data->graph->node_count;
if (x[idx] > LP_EPSILON)
{
log_debug(" edge (%d, %d) = %.2f\n", e->from->index,
e->to->index, x[idx]);
}
}
log_debug(" obj val = %f\n", objval);
added_cuts_count += added_cuts_this_round;
}
CLEANUP:
if (x) free(x);
return rval;
}

2
src/util.h
Unescape View File

@ -9,7 +9,7 @@
#define LOG_LEVEL_DEBUG 40
#define LOG_LEVEL_VERBOSE 50
#define LOG_LEVEL LOG_LEVEL_INFO
#define LOG_LEVEL LOG_LEVEL_DEBUG
#if LOG_LEVEL < LOG_LEVEL_VERBOSE
#define log_verbose(...)