int main() {
igraph_t small, big;
igraph_matrix_t small_coords, big_coords, merged_coords;
igraph_vector_ptr_t graph_ptr, coords_ptr;
igraph_arpack_options_t arpack_opts;
/* To make things reproducible */
igraph_rng_seed(igraph_rng_default(), 42);
igraph_small(&big, 10, IGRAPH_UNDIRECTED,
0,1, 1,2, 2,3, 3,4, 4,5, 5,6, 6,7, 7,8, 8,9, 9,0,
-1);
igraph_small(&small, 3, IGRAPH_UNDIRECTED,
0,1, 1,2, 2,0,
-1);
igraph_arpack_options_init(&arpack_opts);
igraph_matrix_init(&big_coords, 0, 0);
igraph_layout_mds(&big, &big_coords, /*dist=*/ 0, /*dim=*/ 2,
&arpack_opts);
igraph_matrix_init(&small_coords, 0, 0);
igraph_layout_mds(&small, &small_coords, /*dist=*/ 0, /*dim=*/ 2,
&arpack_opts);
igraph_vector_ptr_init(&graph_ptr, 2);
igraph_vector_ptr_init(&coords_ptr, 2);
igraph_matrix_init(&merged_coords, 0, 0);
VECTOR(graph_ptr)[0] = &big;
VECTOR(graph_ptr)[1] = &small;
VECTOR(coords_ptr)[0] = &big_coords;
VECTOR(coords_ptr)[1] = &small_coords;
igraph_layout_merge_dla(&graph_ptr, &coords_ptr, &merged_coords);
igraph_matrix_print(&merged_coords);
igraph_matrix_destroy(&merged_coords);
igraph_matrix_destroy(&small_coords);
igraph_matrix_destroy(&big_coords);
igraph_vector_ptr_destroy(&graph_ptr);
igraph_vector_ptr_destroy(&coords_ptr);
igraph_destroy(&small);
igraph_destroy(&big);
#ifdef __APPLE__
return 0;
#else
return 77;
#endif
}
int main() {
igraph_t graph;
igraph_matrix_t coords;
int i;
igraph_matrix_init(&coords, 0, 0);
for (i=0; i<10; i++) {
igraph_erdos_renyi_game(&graph, IGRAPH_ERDOS_RENYI_GNP, /*n=*/ 100,
/*p=*/ 2.0/100, IGRAPH_UNDIRECTED, /*loops=*/ 0);
igraph_layout_mds(&graph, &coords, /*dist=*/ 0, /*dim=*/ 2,
/*options=*/ 0);
igraph_destroy(&graph);
}
igraph_matrix_destroy(&coords);
return 0;
}
int main() {
float dist[8][8] = {
{0.00, 4.69, 6.79, 3.50, 3.11, 4.46, 5.57, 3.00},
{4.69, 0.00, 2.10, 2.27, 2.65, 2.36, 1.99, 1.74},
{6.79, 2.10, 0.00, 3.78, 4.53, 2.83, 2.44, 3.79},
{3.50, 2.27, 3.78, 0.00, 1.98, 4.35, 2.07, 0.53},
{3.11, 2.65, 4.53, 1.98, 0.00, 3.80, 3.31, 1.47},
{4.46, 2.36, 2.83, 4.35, 3.80, 0.00, 4.35, 3.82},
{5.57, 1.99, 2.44, 2.07, 3.31, 4.35, 0.00, 2.57},
{3.00, 1.74, 3.79, 0.53, 1.47, 3.82, 2.57, 0.00},
};
igraph_t g;
igraph_matrix_t coords, dist_mat;
igraph_real_t vc;
igraph_arpack_options_t options;
int i, j;
srand(time(0));
igraph_arpack_options_init(&options);
igraph_tree(&g, 10, 2, IGRAPH_TREE_UNDIRECTED);
igraph_matrix_init(&coords, 0, 0);
igraph_layout_mds(&g, &coords, 0, 2, &options);
if (MATRIX(coords, 0, 0) > 0) {
for (i = 0; i < igraph_matrix_nrow(&coords); i++)
MATRIX(coords, i, 0) *= -1;
}
if (MATRIX(coords, 0, 1) < 0) {
for (i = 0; i < igraph_matrix_nrow(&coords); i++)
MATRIX(coords, i, 1) *= -1;
}
igraph_matrix_print(&coords);
igraph_matrix_destroy(&coords);
igraph_destroy(&g);
igraph_full(&g, 8, IGRAPH_UNDIRECTED, 0);
igraph_matrix_init(&coords, 8, 2);
igraph_matrix_init(&dist_mat, 8, 8);
for (i = 0; i < 8; i++)
for (j = 0; j < 2; j++)
MATRIX(coords, i, j) = rand() % 1000;
for (i = 0; i < 8; i++)
for (j = i+1; j < 8; j++) {
double dist_sq = 0.0;
dist_sq += sqr(MATRIX(coords, i, 0)-MATRIX(coords, j, 0));
dist_sq += sqr(MATRIX(coords, i, 1)-MATRIX(coords, j, 1));
MATRIX(dist_mat, i, j) = sqrt(dist_sq);
MATRIX(dist_mat, j, i) = sqrt(dist_sq);
}
igraph_layout_mds(&g, &coords, &dist_mat, 2, &options);
for (i = 0; i < 8; i++)
for (j = i+1; j < 8; j++) {
double dist_sq = 0.0;
dist_sq += sqr(MATRIX(coords, i, 0)-MATRIX(coords, j, 0));
dist_sq += sqr(MATRIX(coords, i, 1)-MATRIX(coords, j, 1));
if (fabs(sqrt(dist_sq) - MATRIX(dist_mat, i, j)) > 1e-2) {
printf("dist(%d,%d) should be %.4f, but it is %.4f\n",
i, j, MATRIX(dist_mat, i, j), sqrt(dist_sq));
return 1;
}
}
igraph_matrix_destroy(&dist_mat);
igraph_matrix_destroy(&coords);
igraph_destroy(&g);
return 0;
}