/* -*- mode: C -*- */ /* vim:set ts=2 sw=2 sts=2 et: */ /* IGraph library. Copyright (C) 2011-2012 Gabor Csardi <csardi.gabor@gmail.com> 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 <igraph.h> #include <string.h> int main() { igraph_t g; igraph_vector_t weights, result; igraph_bool_t dag; int retval; igraph_vector_init(&result, 0); igraph_set_error_handler(&igraph_error_handler_printignore); /***********************************************************************/ /* Exact solution with integer programming */ /***********************************************************************/ /* Simple unweighted graph */ igraph_small(&g, 0, IGRAPH_DIRECTED, 0,1, 1,2, 2,0, 2,3, 2,4, 0,4, 4,3, 5,0, 6,5, -1); retval = igraph_feedback_arc_set(&g, &result, 0, IGRAPH_FAS_EXACT_IP); if (retval == IGRAPH_UNIMPLEMENTED) return 77; igraph_vector_print(&result); igraph_delete_edges(&g, igraph_ess_vector(&result)); igraph_is_dag(&g, &dag); if (!dag) return 1; igraph_destroy(&g); /* Simple weighted graph */ igraph_small(&g, 0, IGRAPH_DIRECTED, 0,1, 1,2, 2,0, 2,3, 2,4, 0,4, 4,3, 5,0, 6,5, -1); igraph_vector_init_int_end(&weights, -1, 1, 1, 3, 1, 1, 1, 1, 1, 1, -1); igraph_feedback_arc_set(&g, &result, &weights, IGRAPH_FAS_EXACT_IP); igraph_vector_print(&result); igraph_delete_edges(&g, igraph_ess_vector(&result)); igraph_is_dag(&g, &dag); if (!dag) return 2; igraph_vector_destroy(&weights); igraph_destroy(&g); /* Simple unweighted graph with loops */ igraph_small(&g, 0, IGRAPH_DIRECTED, 0,1, 1,2, 2,0, 2,3, 2,4, 0,4, 4,3, 5,0, 6,5, 1,1, 4,4, -1); igraph_feedback_arc_set(&g, &result, 0, IGRAPH_FAS_EXACT_IP); igraph_vector_print(&result); igraph_delete_edges(&g, igraph_ess_vector(&result)); igraph_is_dag(&g, &dag); if (!dag) return 3; igraph_destroy(&g); /* Disjoint union of two almost identical graphs */ igraph_small(&g, 0, IGRAPH_DIRECTED, 0,1, 1,2, 2,0, 2,3, 2,4, 0,4, 4,3, 5,0, 6,5, 1,1, 4,4, 7,8, 8,9, 9,7, 9,10, 9,11, 7,11, 11,10, 12,7, 13,12, -1); igraph_feedback_arc_set(&g, &result, 0, IGRAPH_FAS_EXACT_IP); igraph_vector_print(&result); igraph_delete_edges(&g, igraph_ess_vector(&result)); igraph_is_dag(&g, &dag); if (!dag) return 4; igraph_destroy(&g); igraph_vector_destroy(&result); return 0; }