Add graph references

2026-06-28 13:49:01 +01:00
parent 0a9807e448
commit a11edf0c53
2578 changed files with 868045 additions and 0 deletions
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+/*
+
+  Copyright 2017 The Johns Hopkins University Applied Physics Laboratory LLC. All Rights Reserved.
+  Copyright 2021 The igraph team
+
+  Truss algorithm for cohesive subgroups.
+
+  Author: Alex Perrone
+  Date: 2017-08-03
+  Minor edits: The igraph team, 2021
+
+  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 <stdio.h>
+#include <igraph.h>
+
+#include "test_utilities.h"
+
+void print_and_destroy(igraph_t *graph, igraph_vector_int_t *trussness) {
+    igraph_int_t i, n = igraph_vector_int_size(trussness);
+
+    printf("fromNode, toNode, trussness\n");
+    for (i=0; i < n; i++) {
+        igraph_int_t from, to;
+        igraph_edge(graph, i, &from, &to);
+        printf("%" IGRAPH_PRId ", %" IGRAPH_PRId ", %" IGRAPH_PRId "\n", from, to, VECTOR(*trussness)[i]);
+    }
+
+    igraph_vector_int_destroy(trussness);
+    igraph_destroy(graph);
+}
+
+int main(void) {
+
+    igraph_t graph;
+    igraph_vector_int_t trussness;
+
+    /* Create actual graph */
+    igraph_int_t edges[] = { 0,1, 0,2, 0,3, 0,4,
+      1,2, 1,3, 1,4, 2,3, 2,4, 3,4, 3,6, 3,11,
+      4,5, 4,6, 5,6, 5,7, 5,8, 5,9, 6,7, 6,10, 6,11,
+      7,8, 7,9, 8,9, 8,10 };
+    const igraph_vector_int_t v = igraph_vector_int_view(edges, sizeof(edges) / sizeof(edges[0]));
+
+    igraph_create(&graph, &v, 0, IGRAPH_UNDIRECTED);
+
+    /* Compute the trussness of the edges. */
+    printf("Simple graph:\n");
+    igraph_vector_int_init(&trussness, 0);
+    igraph_trussness(&graph, &trussness);
+    print_and_destroy(&graph, &trussness);
+
+    /* Add some loop edges -- they should have trussness = 2 */
+    printf("\nGraph with loops:\n");
+    igraph_create(&graph, &v, 0, IGRAPH_UNDIRECTED);
+    igraph_add_edge(&graph, 0, 0);
+    igraph_add_edge(&graph, 7, 7);
+    igraph_add_edge(&graph, 5, 5);
+    igraph_vector_int_init(&trussness, 0);
+    igraph_trussness(&graph, &trussness);
+    print_and_destroy(&graph, &trussness);
+
+    /* Null graph trivial case */
+    printf("\nNull graph:\n");
+    igraph_empty(&graph, 0, IGRAPH_UNDIRECTED);
+    igraph_vector_int_init(&trussness, 0);
+    igraph_trussness(&graph, &trussness);
+    print_and_destroy(&graph, &trussness);
+
+    /* Singleton graph trivial case */
+    printf("\nSingleton graph:\n");
+    igraph_empty(&graph, 1, IGRAPH_UNDIRECTED);
+    igraph_vector_int_init(&trussness, 0);
+    igraph_trussness(&graph, &trussness);
+    print_and_destroy(&graph, &trussness);
+
+    /* Graph with no edges trivial case */
+    printf("\nGraph with no edges:\n");
+    igraph_empty(&graph, 10, IGRAPH_UNDIRECTED);
+    igraph_vector_int_init(&trussness, 0);
+    igraph_trussness(&graph, &trussness);
+    print_and_destroy(&graph, &trussness);
+
+    VERIFY_FINALLY_STACK();
+
+    /* Multigraph */
+    printf("\nTrying multigraph:\n");
+    igraph_create(&graph, &v, 0, IGRAPH_UNDIRECTED);
+    igraph_to_directed(&graph, IGRAPH_TO_DIRECTED_MUTUAL);
+    igraph_to_undirected(&graph, IGRAPH_TO_UNDIRECTED_EACH, 0);
+    igraph_vector_int_init(&trussness, 0);
+    CHECK_ERROR(igraph_trussness(&graph, &trussness), IGRAPH_UNIMPLEMENTED);
+    igraph_vector_int_destroy(&trussness);
+    igraph_destroy(&graph);
+
+    return 0;
+}