/* igraph library. Copyright (C) 2006-2012 Gabor Csardi 334 Harvard street, Cambridge, MA 02139 USA This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include "test_utilities.h" #define TOL (1e-15) void run_leiden_CPM(const igraph_t *graph, const igraph_vector_t *edge_weights, const igraph_real_t resolution) { igraph_vector_int_t membership; igraph_int_t nb_clusters = igraph_vcount(graph); igraph_real_t quality, quality2; /* Initialize with singleton partition. */ igraph_vector_int_init(&membership, igraph_vcount(graph)); /* Use same seed as for the simplified interface below, to ensure the same result. */ igraph_rng_seed(igraph_rng_default(), 123); igraph_community_leiden(graph, edge_weights, NULL, NULL, resolution, 0.01, false, 2, &membership, &nb_clusters, &quality); /* Handle negative zeros. */ if (fabs(quality) < TOL) quality = 0.0; printf("Leiden found %" IGRAPH_PRId " clusters using CPM (resolution parameter=%.2f), quality is %.5f.\n", nb_clusters, resolution, quality); printf("Membership: "); igraph_vector_int_print(&membership); printf("\n"); quality2 = quality; /* Use same seed as for the generic interface above, to ensure the same result. */ igraph_rng_seed(igraph_rng_default(), 123); igraph_community_leiden_simple(graph, edge_weights, IGRAPH_LEIDEN_OBJECTIVE_CPM, resolution, 0.01, false, 2, &membership, NULL, &quality); if (fabs(quality) < TOL) quality = 0.0; IGRAPH_ASSERT((isnan(quality) && isnan(quality2)) || igraph_almost_equals(quality, quality2, TOL)); igraph_vector_int_destroy(&membership); } void run_leiden_modularity(igraph_t *graph, igraph_vector_t *edge_weights) { const igraph_bool_t directed = igraph_is_directed(graph); igraph_vector_int_t membership; igraph_vector_t out_strength, in_strength; igraph_int_t nb_clusters = igraph_vcount(graph); igraph_real_t quality, quality2; const igraph_real_t directed_multiplier = directed ? 1.0 : 2.0; igraph_real_t m; igraph_vector_init(&out_strength, igraph_vcount(graph)); igraph_strength(graph, &out_strength, igraph_vss_all(), IGRAPH_OUT, IGRAPH_LOOPS, edge_weights); if (directed) { igraph_vector_init(&in_strength, igraph_vcount(graph)); igraph_strength(graph, &in_strength, igraph_vss_all(), IGRAPH_IN, IGRAPH_LOOPS, edge_weights); } m = edge_weights ? igraph_vector_sum(edge_weights) : igraph_ecount(graph); /* Initialize with singleton partition. */ igraph_vector_int_init(&membership, igraph_vcount(graph)); /* Use same seed as for the simplified interface below, to ensure the same result. */ igraph_rng_seed(igraph_rng_default(), 123); igraph_community_leiden(graph, edge_weights, &out_strength, directed ? &in_strength : NULL, 1.0 / (directed_multiplier * m), 0.01, false, 2, &membership, &nb_clusters, &quality); igraph_modularity(graph, &membership, edge_weights, 1.0, IGRAPH_DIRECTED, &quality2); if (isnan(quality)) { printf("Leiden found %" IGRAPH_PRId " clusters using modularity, %s, quality is nan.\n", nb_clusters, directed ? "directed" : "undirected"); IGRAPH_ASSERT(isnan(quality2)); } else { /* It is necessary to not only use igraph_almost_equals(), but also check * if the values are both very close to zero due to roundoff errors. */ if (fabs(quality) < TOL) quality = 0.0; if (fabs(quality2) < TOL) quality2 = 0.0; printf("Leiden found %" IGRAPH_PRId " clusters using modularity, %s, quality is %.5f.\n", nb_clusters, directed ? "directed" : "undirected", quality); IGRAPH_ASSERT(igraph_almost_equals(quality, quality2, TOL)); } printf("Membership: "); igraph_vector_int_print(&membership); printf("\n"); /* Use same seed as for the generic interface above, to ensure the same result. */ igraph_rng_seed(igraph_rng_default(), 123); igraph_community_leiden_simple(graph, edge_weights, IGRAPH_LEIDEN_OBJECTIVE_MODULARITY, 1.0, 0.01, false, 2, &membership, NULL, &quality); if (fabs(quality) < TOL) quality = 0.0; IGRAPH_ASSERT((isnan(quality) && isnan(quality2)) || igraph_almost_equals(quality, quality2, TOL)); igraph_vector_int_destroy(&membership); if (directed) igraph_vector_destroy(&in_strength); igraph_vector_destroy(&out_strength); } int main(void) { igraph_t graph; igraph_vector_t weights; igraph_vector_init(&weights, 0); /* Set default seed to get reproducible results */ igraph_rng_seed(igraph_rng_default(), 0); /* Simple unweighted graph */ igraph_small(&graph, 10, IGRAPH_UNDIRECTED, 0, 1, 0, 2, 0, 3, 0, 4, 1, 2, 1, 3, 1, 4, 2, 3, 2, 4, 3, 4, 5, 6, 5, 7, 5, 8, 5, 9, 6, 7, 6, 8, 6, 9, 7, 8, 7, 9, 8, 9, 0, 5, -1); run_leiden_modularity(&graph, NULL); /* Same simple graph, with uniform edge weights */ igraph_vector_resize(&weights, igraph_ecount(&graph)); igraph_vector_fill(&weights, 2); run_leiden_modularity(&graph, &weights); /* Same simple graph, but directed with reciprocal edges */ igraph_to_directed(&graph, IGRAPH_TO_DIRECTED_MUTUAL); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* Tiny directed graph; optimal community structure is different if * ignoring edge directions. */ igraph_small(&graph, 4, IGRAPH_DIRECTED, 0, 2, 0, 3, 1, 2, 3, 1, 3, 2, -1); run_leiden_modularity(&graph, NULL); igraph_to_undirected(&graph, IGRAPH_TO_UNDIRECTED_EACH, NULL); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* Larger directed graph; optimal community structure is different if * ignoring edge directions. */ igraph_small( &graph, 10, IGRAPH_DIRECTED, 0, 3, 0, 4, 1, 0, 1, 4, 2, 1, 3, 0, 3, 2, 4, 0, 4, 3, 4, 7, 5, 0, 5, 1, 5, 3, 5, 6, 5, 8, 5, 9, 7, 0, 8, 2, 8, 3, 9, 1, 9, 3, 9, 8, -1); run_leiden_modularity(&graph, NULL); igraph_to_undirected(&graph, IGRAPH_TO_UNDIRECTED_EACH, NULL); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* Simple nonuniform weighted graph, with and without weights */ igraph_small(&graph, 6, IGRAPH_UNDIRECTED, 0, 1, 1, 2, 2, 3, 2, 4, 2, 5, 3, 4, 3, 5, 4, 5, -1); igraph_vector_resize(&weights, 8); igraph_vector_fill(&weights, 1); VECTOR(weights)[0] = 10; VECTOR(weights)[1] = 10; run_leiden_modularity(&graph, NULL); run_leiden_modularity(&graph, &weights); igraph_destroy(&graph); /* Zachary Karate club */ igraph_small(&graph, 0, IGRAPH_UNDIRECTED, 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0, 8, 0, 10, 0, 11, 0, 12, 0, 13, 0, 17, 0, 19, 0, 21, 0, 31, 1, 2, 1, 3, 1, 7, 1, 13, 1, 17, 1, 19, 1, 21, 1, 30, 2, 3, 2, 7, 2, 8, 2, 9, 2, 13, 2, 27, 2, 28, 2, 32, 3, 7, 3, 12, 3, 13, 4, 6, 4, 10, 5, 6, 5, 10, 5, 16, 6, 16, 8, 30, 8, 32, 8, 33, 9, 33, 13, 33, 14, 32, 14, 33, 15, 32, 15, 33, 18, 32, 18, 33, 19, 33, 20, 32, 20, 33, 22, 32, 22, 33, 23, 25, 23, 27, 23, 29, 23, 32, 23, 33, 24, 25, 24, 27, 24, 31, 25, 31, 26, 29, 26, 33, 27, 33, 28, 31, 28, 33, 29, 32, 29, 33, 30, 32, 30, 33, 31, 32, 31, 33, 32, 33, -1); run_leiden_modularity(&graph, NULL); run_leiden_CPM(&graph, NULL, 0.06); igraph_destroy(&graph); /* Simple disconnected graph with isolates */ igraph_small(&graph, 9, IGRAPH_UNDIRECTED, 0, 1, 0, 2, 0, 3, 1, 2, 1, 3, 2, 3, 4, 5, 4, 6, 4, 7, 5, 6, 5, 7, 6, 7, -1); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* Disjoint union of two rings */ igraph_small(&graph, 20, IGRAPH_UNDIRECTED, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 0, 9, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 10, 19, -1); run_leiden_modularity(&graph, NULL); run_leiden_CPM(&graph, NULL, 0.05); igraph_destroy(&graph); /* Completely empty graph */ igraph_small(&graph, 10, IGRAPH_UNDIRECTED, -1); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* Set default seed to get reproducible results */ igraph_rng_seed(igraph_rng_default(), 0); /* Ring graph without loop edges */ igraph_small(&graph, 6, IGRAPH_UNDIRECTED, 0,1, 1,2, 2,3, 3,4, 4,5, 5,0, -1); run_leiden_CPM(&graph, NULL, 0.4); igraph_destroy(&graph); /* Set default seed to get reproducible results */ igraph_rng_seed(igraph_rng_default(), 0); /* Ring graph with loop edges */ igraph_small(&graph, 6, IGRAPH_UNDIRECTED, 0,1, 1,2, 2,3, 3,4, 4,5, 5,0, 0,0, 1,1, 2,2, 3,3, 4,4, 5,5, -1); run_leiden_CPM(&graph, NULL, 0.4); igraph_destroy(&graph); /* Regression test -- graph with two vertices and two edges */ igraph_small(&graph, 2, IGRAPH_UNDIRECTED, 0, 0, 1, 1, -1); run_leiden_modularity(&graph, NULL); igraph_destroy(&graph); /* The next two tests need an empty weight vector. */ igraph_vector_clear(&weights); /* Null graph */ igraph_empty(&graph, 0, IGRAPH_UNDIRECTED); run_leiden_modularity(&graph, &weights); igraph_destroy(&graph); /* Edgeless graph */ igraph_empty(&graph, 5, IGRAPH_UNDIRECTED); run_leiden_modularity(&graph, &weights); igraph_destroy(&graph); /* Check that the input is validated properly. */ /* Small test graph. */ igraph_small(&graph, 4, IGRAPH_UNDIRECTED, 0,1, 1,2, 2,0, 0,3, 3,3, -1); igraph_vector_range(&weights, 1, igraph_ecount(&graph) + 1); /* Omitting membership should raise no error. */ igraph_community_leiden_simple(&graph, &weights, IGRAPH_LEIDEN_OBJECTIVE_MODULARITY, 1.0, 0.01, false, 1, NULL, NULL, NULL); /* Negative weight. */ VECTOR(weights)[0] = -1; CHECK_ERROR(igraph_community_leiden_simple(&graph, &weights, IGRAPH_LEIDEN_OBJECTIVE_MODULARITY, 1.0, 0.01, false, 1, NULL, NULL, NULL), IGRAPH_EINVAL); CHECK_ERROR(igraph_community_leiden_simple(&graph, &weights, IGRAPH_LEIDEN_OBJECTIVE_ER, 1.0, 0.01, false, 1, NULL, NULL, NULL), IGRAPH_EINVAL); /* NaN weight. */ VECTOR(weights)[0] = IGRAPH_NAN; CHECK_ERROR(igraph_community_leiden_simple(&graph, &weights, IGRAPH_LEIDEN_OBJECTIVE_CPM, 1.0, 0.01, false, 1, NULL, NULL, NULL), IGRAPH_EINVAL); /* Invalid weight vector length. */ igraph_vector_range(&weights, 1, igraph_ecount(&graph) + 2); CHECK_ERROR(igraph_community_leiden_simple(&graph, &weights, IGRAPH_LEIDEN_OBJECTIVE_MODULARITY, 1.0, 0.01, false, 1, NULL, NULL, NULL), IGRAPH_EINVAL); igraph_destroy(&graph); igraph_vector_destroy(&weights); VERIFY_FINALLY_STACK(); return 0; }