/* -*- mode: C -*- */ /* vim:set ts=4 sw=4 sts=4 et: */ /* IGraph library. Copyright (C) 2006-2012 Gabor Csardi 334 Harvard st, 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 /* Compares two paths based on their last elements. If they are equal, proceeds * with the ones preceding these elements, until we find a difference. If one * of the vectors is a suffix of the other, the shorter vector gets ordered * first. */ int vector_tail_cmp(const void *path1, const void *path2) { const igraph_vector_t *vec1 = *(const igraph_vector_t**)path1; const igraph_vector_t *vec2 = *(const igraph_vector_t**)path2; size_t length1 = igraph_vector_size(vec1); size_t length2 = igraph_vector_size(vec2); int diff; while (length1 > 0 && length2 > 0) { length1--; length2--; diff = VECTOR(*vec1)[length1] - VECTOR(*vec2)[length2]; if (diff != 0) { return diff; } } if (length1 == 0 && length2 == 0) { return 0; } else if (length1 == 0) { return -1; } else { return 1; } } void check_nrgeo(const igraph_t *graph, igraph_vs_t vs, const igraph_vector_ptr_t *paths, const igraph_vector_t *nrgeo) { long int i, n; igraph_vector_t nrgeo2, *path; igraph_vit_t vit; n = igraph_vcount(graph); igraph_vector_init(&nrgeo2, n); if (igraph_vector_size(nrgeo) != n) { printf("nrgeo vector length must be %ld, was %ld", n, igraph_vector_size(nrgeo)); return; } n = igraph_vector_ptr_size(paths); for (i = 0; i < n; i++) { path = VECTOR(*paths)[i]; if (path == 0) { printf("Null path found in result vector at index %ld\n", i); return; } if (igraph_vector_size(path) == 0) { printf("Empty path found in result vector at index %ld\n", i); return; } VECTOR(nrgeo2)[(long int)igraph_vector_tail(path)] += 1; } igraph_vit_create(graph, vs, &vit); for (IGRAPH_VIT_RESET(vit); !IGRAPH_VIT_END(vit); IGRAPH_VIT_NEXT(vit)) { long int node = IGRAPH_VIT_GET(vit); if (VECTOR(*nrgeo)[node] - VECTOR(nrgeo2)[node]) { printf("nrgeo[%ld] invalid, observed = %ld, expected = %ld\n", node, (long int)VECTOR(*nrgeo)[node], (long int)VECTOR(nrgeo2)[node]); } } igraph_vit_destroy(&vit); igraph_vector_destroy(&nrgeo2); } int main() { igraph_t g; igraph_vector_ptr_t res; long int i; igraph_real_t weights[] = { 1, 2, 3, 4, 5, 1, 1, 1, 1, 1 }; igraph_real_t weights2[] = { 0, 2, 1, 0, 5, 2, 1, 1, 0, 2, 2, 8, 1, 1, 3, 1, 1, 4, 2, 1 }; igraph_real_t dim[] = { 4, 4 }; igraph_vector_t weights_vec, dim_vec, nrgeo; igraph_vs_t vs; igraph_vector_init(&nrgeo, 0); /* Simple ring graph without weights */ igraph_ring(&g, 10, IGRAPH_UNDIRECTED, 0, 1); igraph_vector_ptr_init(&res, 5); igraph_vs_vector_small(&vs, 1, 3, 4, 5, 2, 1, -1); igraph_get_all_shortest_paths_dijkstra( &g, /*res=*/ &res, /*nrgeo=*/ &nrgeo, /*from=*/ 0, /*to=*/ vs, /*weights=*/ NULL, /*mode=*/ IGRAPH_OUT); check_nrgeo(&g, vs, &res, &nrgeo); for (i = 0; i < igraph_vector_ptr_size(&res); i++) { igraph_vector_print(VECTOR(res)[i]); igraph_vector_destroy(VECTOR(res)[i]); igraph_free(VECTOR(res)[i]); VECTOR(res)[i] = 0; } /* Same ring, but with weights */ igraph_vector_view(&weights_vec, weights, sizeof(weights) / sizeof(igraph_real_t)); igraph_get_all_shortest_paths_dijkstra( &g, /*res=*/ &res, /*nrgeo=*/ &nrgeo, /*from=*/ 0, /*to=*/ vs, /*weights=*/ &weights_vec, /*mode=*/ IGRAPH_OUT); check_nrgeo(&g, vs, &res, &nrgeo); for (i = 0; i < igraph_vector_ptr_size(&res); i++) { igraph_vector_print(VECTOR(res)[i]); igraph_vector_destroy(VECTOR(res)[i]); igraph_free(VECTOR(res)[i]); VECTOR(res)[i] = 0; } igraph_destroy(&g); /* More complicated example */ igraph_small(&g, 10, IGRAPH_DIRECTED, 0, 1, 0, 2, 0, 3, 1, 2, 1, 4, 1, 5, 2, 3, 2, 6, 3, 2, 3, 6, 4, 5, 4, 7, 5, 6, 5, 8, 5, 9, 7, 5, 7, 8, 8, 9, 5, 2, 2, 1, -1); igraph_vector_view(&weights_vec, weights2, sizeof(weights2) / sizeof(igraph_real_t)); igraph_get_all_shortest_paths_dijkstra( &g, /*res=*/ &res, /*nrgeo=*/ &nrgeo, /*from=*/ 0, /*to=*/ vs, /*weights=*/ &weights_vec, /*mode=*/ IGRAPH_OUT); check_nrgeo(&g, vs, &res, &nrgeo); /* Sort the paths in a deterministic manner to avoid problems with * different qsort() implementations on different platforms */ igraph_vector_ptr_sort(&res, vector_tail_cmp); for (i = 0; i < igraph_vector_ptr_size(&res); i++) { igraph_vector_print(VECTOR(res)[i]); igraph_vector_destroy(VECTOR(res)[i]); igraph_free(VECTOR(res)[i]); VECTOR(res)[i] = 0; } igraph_vs_destroy(&vs); igraph_destroy(&g); /* Regular lattice with some heavyweight edges */ igraph_vector_view(&dim_vec, dim, sizeof(dim) / sizeof(igraph_real_t)); igraph_lattice(&g, &dim_vec, 1, 0, 0, 0); igraph_vs_vector_small(&vs, 3, 12, 15, -1); igraph_vector_init(&weights_vec, 24); igraph_vector_fill(&weights_vec, 1); VECTOR(weights_vec)[2] = 100; VECTOR(weights_vec)[8] = 100; /* 1-->2, 4-->8 */ igraph_get_all_shortest_paths_dijkstra( &g, /*res=*/ 0, /*nrgeo=*/ &nrgeo, /*from=*/ 0, /*to=*/ vs, /*weights=*/ &weights_vec, /*mode=*/ IGRAPH_OUT); igraph_vector_destroy(&weights_vec); igraph_vs_destroy(&vs); igraph_destroy(&g); printf("%ld ", (long int)VECTOR(nrgeo)[3]); printf("%ld ", (long int)VECTOR(nrgeo)[12]); printf("%ld\n", (long int)VECTOR(nrgeo)[15]); igraph_vector_ptr_destroy(&res); igraph_vector_destroy(&nrgeo); if (!IGRAPH_FINALLY_STACK_EMPTY) { return 1; } return 0; }