int minimum_disjoint_path_covering(graph_matrix g)
{//简单有向图G有g_cnt个节点，下标从0到g_cnt-1
//若从节点i指向节点j存在有向边则g_m[i][j]为1
//同一节点的g_m值为0，不相连节点的g_m值为INF
//返回最小不相交路径覆盖数
bipartite b;
int xmatch[MAX], ymatch[MAX];
memset(xmatch, -1, MAX * sizeof(int));
memset(ymatch, -1, MAX * sizeof(int));
construct_b(g, b);
return(g.g_cnt - hopcroft_karp(b, xmatch, ymatch));
}
int
compute_y_coords(vtx_data * graph, int n, double *y_coords,
int max_iterations)
{
/* Find y coords of a directed graph by solving L*x = b */
int i, j, rv = 0;
double *b = N_NEW(n, double);
double tol = hierarchy_cg_tol;
int nedges = 0;
float *uniform_weights;
float *old_ewgts = graph[0].ewgts;
construct_b(graph, n, b);
init_vec_orth1(n, y_coords);
for (i = 0; i < n; i++) {
nedges += graph[i].nedges;
}
/* replace original edge weights (which are lengths) with uniform weights */
/* for computing the optimal arrangement */
uniform_weights = N_GNEW(nedges, float);
for (i = 0; i < n; i++) {
graph[i].ewgts = uniform_weights;
uniform_weights[0] = (float) -(graph[i].nedges - 1);
for (j = 1; j < graph[i].nedges; j++) {
uniform_weights[j] = 1;
}
uniform_weights += graph[i].nedges;
}
if (conjugate_gradient(graph, y_coords, b, n, tol, max_iterations) < 0) {
rv = 1;
}
/* restore original edge weights */
free(graph[0].ewgts);
for (i = 0; i < n; i++) {
graph[i].ewgts = old_ewgts;
old_ewgts += graph[i].nedges;
}
free(b);
return rv;
}
