Add graph references

2026-06-28 13:49:01 +01:00
parent 0a9807e448
commit a11edf0c53
2578 changed files with 868045 additions and 0 deletions
@@ -0,0 +1,90 @@
+/*
+   igraph library.
+   Copyright (C) 2021  The igraph development team <igraph@igraph.org>
+
+   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, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <igraph.h>
+
+#include "test_utilities.h"
+
+int main(void) {
+
+    igraph_t g;
+    igraph_real_t result;
+    igraph_int_t from, to;
+    igraph_vector_int_t path_edge, path_vertex, edge_vec;
+    igraph_int_t vec[] = {2,8};
+    igraph_es_t edge_sele;
+
+    printf("diameter of Barabasi graph:\n");
+
+    igraph_rng_seed(igraph_rng_default(), 1234);
+    igraph_barabasi_game(&g, 30, /*power=*/ 1, 30, 0, 0, /*A=*/ 1,
+                         IGRAPH_DIRECTED, IGRAPH_BARABASI_BAG,
+                         /*start_from=*/ 0);
+    igraph_diameter(&g, NULL, &result, NULL, NULL, NULL, NULL, IGRAPH_UNDIRECTED, 1);
+
+    printf("Diameter: %" IGRAPH_PRId "\n", (igraph_int_t) result);
+
+    igraph_destroy(&g);
+
+    printf("diameter of ring and the path in terms of edges and vertices \n");
+
+    igraph_ring(&g, 10, IGRAPH_DIRECTED, 0, 0);
+    igraph_vector_int_init(&path_vertex, 0);
+    igraph_vector_int_init(&path_edge, 0);
+    igraph_diameter(&g, NULL, &result, &from, &to, &path_vertex, &path_edge, IGRAPH_DIRECTED, 1);
+    printf("diameter: %g, from %" IGRAPH_PRId " to %" IGRAPH_PRId "\n", result,
+            from, to);
+    print_vector_int(&path_vertex);
+    print_vector_int(&path_edge);
+    igraph_vector_int_destroy(&path_vertex);
+    igraph_vector_int_destroy(&path_edge);
+
+    //disconnected graph
+    printf("disconnected ring graph\n");
+    edge_vec = igraph_vector_int_view(vec, sizeof(vec) / sizeof(vec[0]));
+    igraph_es_vector(&edge_sele, &edge_vec);
+    igraph_delete_edges(&g, edge_sele);
+    printf("The largest path in one connected component\n");
+    igraph_diameter(&g, NULL, &result, NULL, NULL, NULL, NULL, IGRAPH_DIRECTED, 1);
+    print_real(stdout, result, "%g");
+    printf("\nuconn = False \n");
+    igraph_diameter(&g, NULL, &result, NULL, NULL, NULL, NULL, IGRAPH_DIRECTED, 0);
+    print_real(stdout, result, "%g");
+
+    igraph_es_destroy(&edge_sele);
+    igraph_destroy(&g);
+
+    // test graph with zero nodes
+    printf("\ngraph with zero nodes\n");
+    igraph_empty(&g, 0, IGRAPH_DIRECTED);
+    igraph_diameter(&g, NULL, &result, &from, &to, NULL, NULL, IGRAPH_DIRECTED, 1);
+    print_real(stdout, result, "%g");
+    printf("\nfrom = %" IGRAPH_PRId ", to = %" IGRAPH_PRId "\n", from, to);
+    igraph_destroy(&g);
+
+    //test graph with one node
+    printf("graph with one node\n");
+    igraph_empty(&g, 1, IGRAPH_DIRECTED);
+    igraph_diameter(&g, NULL, &result, &from, &to, NULL, NULL, IGRAPH_DIRECTED, 1);
+    print_real(stdout, result, "%g");
+    printf("\nfrom = %" IGRAPH_PRId ", to = %" IGRAPH_PRId "\n", from, to);
+    igraph_destroy(&g);
+
+    VERIFY_FINALLY_STACK();
+    return 0;
+}