Abdelrahman Said
185 lines
6.7 KiB
C
185 lines
6.7 KiB
C
/*
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igraph library.
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Copyright (C) 2022 The igraph development team <igraph@igraph.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <igraph.h>
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#include "test_utilities.h"
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void print_check_destroy(igraph_t *graph, igraph_vector_int_list_t *result) {
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igraph_int_t i, rank = igraph_vector_int_list_size(result);
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igraph_int_t ecount = igraph_ecount(graph), vcount = igraph_vcount(graph);
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igraph_int_t ccount;
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for (i=0; i < rank; ++i) {
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igraph_vector_int_t *cycle = igraph_vector_int_list_get_ptr(result, i);
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IGRAPH_ASSERT(igraph_vector_int_size(cycle) > 0);
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igraph_int_t first_edge = VECTOR(*cycle)[0];
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igraph_int_t last_edge = VECTOR(*cycle)[igraph_vector_int_size(cycle) - 1];
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/* Verify that first and last edges of the cycle share a vertex */
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IGRAPH_ASSERT(
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(IGRAPH_FROM(graph, first_edge) == IGRAPH_FROM(graph, last_edge) ||
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IGRAPH_FROM(graph, first_edge) == IGRAPH_TO(graph, last_edge)) ||
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(IGRAPH_TO(graph, first_edge) == IGRAPH_FROM(graph, last_edge) ||
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IGRAPH_TO(graph, first_edge) == IGRAPH_TO(graph, last_edge))
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);
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print_vector_int(cycle);
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}
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igraph_connected_components(graph, NULL, NULL, &ccount, IGRAPH_WEAK);
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IGRAPH_ASSERT(rank == ecount - vcount + ccount);
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igraph_destroy(graph);
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}
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int main(void) {
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igraph_t graph;
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igraph_vector_int_list_t result;
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igraph_int_t rank;
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igraph_vector_int_list_init(&result, 0);
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printf("FUNDAMENTAL CYCLE BASIS\n");
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printf("\nNull graph\n");
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igraph_empty(&graph, 0, IGRAPH_UNDIRECTED);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\nSingleton graph\n");
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igraph_empty(&graph, 1, IGRAPH_UNDIRECTED);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\nSingle vertex with loop\n");
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igraph_small(&graph, 1, IGRAPH_UNDIRECTED,
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0,0,
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-1);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\nTree\n");
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igraph_kary_tree(&graph, 3, 2, IGRAPH_TREE_UNDIRECTED);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\n2-cycle\n");
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igraph_small(&graph, 0, IGRAPH_UNDIRECTED,
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0,1, 0,1,
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-1);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\nDisconnected\n");
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igraph_small(&graph, 0, IGRAPH_UNDIRECTED,
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1,2, 2,3, 3,1,
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4,5, 5,4, 4,5,
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6,7, 7,8, 8,9, 9,6, 6,8,
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10,10, 10,11,
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12,12,
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-1);
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igraph_fundamental_cycles(&graph, NULL, &result, -1, -1);
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print_check_destroy(&graph, &result);
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printf("\nMINIMUM WEIGHT CYCLE BASIS\n");
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printf("\nNull graph\n");
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igraph_empty(&graph, 0, IGRAPH_UNDIRECTED);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\nSingleton graph\n");
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igraph_empty(&graph, 1, IGRAPH_UNDIRECTED);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\nSingle vertex with loop\n");
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igraph_small(&graph, 1, IGRAPH_UNDIRECTED,
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0,0,
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-1);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\nTree\n");
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igraph_kary_tree(&graph, 3, 2, IGRAPH_TREE_UNDIRECTED);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\n2-cycle\n");
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igraph_small(&graph, 0, IGRAPH_UNDIRECTED,
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0,1, 0,1,
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-1);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\nDisconnected\n");
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igraph_small(&graph, 0, IGRAPH_UNDIRECTED,
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1,2, 2,3, 3,1,
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4,5, 5,4, 4,5,
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6,7, 7,8, 8,9, 9,6, 6,8,
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10,10, 10,11,
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12,12,
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-1);
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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print_check_destroy(&graph, &result);
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printf("\nPeriodic (5,6)-grid\n");
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{
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igraph_vector_int_t dimvec;
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igraph_vector_bool_t periodic;
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igraph_vector_int_init_int_end(&dimvec, -1,
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1, 5, 6, -1);
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igraph_vector_bool_init(&periodic, igraph_vector_int_size(&dimvec));
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igraph_vector_bool_fill(&periodic, 1);
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igraph_square_lattice(&graph, &dimvec, 1, IGRAPH_ADJ_UNDIRECTED, /* mutual */ false, &periodic);
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igraph_vector_bool_destroy(&periodic);
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igraph_vector_int_destroy(&dimvec);
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}
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igraph_minimum_cycle_basis(&graph, NULL, &result, /* cutoff */ -1, /* complete */ true, /* ordered */ true);
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rank = igraph_vector_int_list_size(&result);
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/* In a periodic grid graph, all elements in the minimum basis have size 4,
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* except two, which have size equal to the grid dimensions. */
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IGRAPH_ASSERT(igraph_vector_int_size(&VECTOR(result)[0]) == 4);
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IGRAPH_ASSERT(igraph_vector_int_size(&VECTOR(result)[rank-1]) == 6);
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IGRAPH_ASSERT(igraph_vector_int_size(&VECTOR(result)[rank-2]) == 5);
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IGRAPH_ASSERT(igraph_vector_int_size(&VECTOR(result)[rank-3]) == 4);
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print_check_destroy(&graph, &result);
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#if 0
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/* This is for benchmarking */
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igraph_rng_seed(igraph_rng_default(), 42);
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igraph_watts_strogatz_game(&graph, 3, 10, 2, 0.1, 0, 0);
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igraph_minimum_cycle_basis(&graph, /* cutoff */ -1, /* complete */ true, * ordered */ true, &result);
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print_check_destroy(&graph, &result);
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#endif
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igraph_vector_int_list_destroy(&result);
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VERIFY_FINALLY_STACK();
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return 0;
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}
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