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 +1,33 @@
+#include <igraph.h>
+
+int main(void) {
+    igraph_int_t num_vertices = 1000;
+    igraph_int_t num_edges = 1000;
+    igraph_real_t diameter, mean_degree;
+    igraph_t graph;
+
+    /* Initialize the library. */
+    igraph_setup();
+
+    /* Ensure identical results across runs. */
+    igraph_rng_seed(igraph_rng_default(), 42);
+
+    igraph_erdos_renyi_game_gnm(
+            &graph, num_vertices, num_edges,
+            IGRAPH_UNDIRECTED, IGRAPH_SIMPLE_SW, IGRAPH_EDGE_UNLABELED);
+
+    igraph_diameter(
+        &graph, /* weights = */ NULL,
+        &diameter,
+        /* from = */ NULL, /* to = */ NULL,
+        /* vertex_path = */ NULL, /* edge_path = */ NULL,
+        IGRAPH_UNDIRECTED, /* unconn= */ true);
+
+    igraph_mean_degree(&graph, &mean_degree, IGRAPH_LOOPS);
+    printf("Diameter of a random graph with average degree %g: %g\n",
+           mean_degree, diameter);
+
+    igraph_destroy(&graph);
+
+    return 0;
+}
@@ -0,0 +1,45 @@
+#include <igraph.h>
+
+int main(void) {
+    igraph_t graph;
+    igraph_vector_int_t dimvector;
+    igraph_vector_int_t edges;
+    igraph_vector_bool_t periodic;
+    igraph_real_t avg_path_len;
+
+    /* Initialize the library. */
+    igraph_setup();
+
+    igraph_vector_int_init(&dimvector, 2);
+    VECTOR(dimvector)[0] = 30;
+    VECTOR(dimvector)[1] = 30;
+
+    igraph_vector_bool_init(&periodic, 2);
+    igraph_vector_bool_fill(&periodic, true);
+    igraph_square_lattice(&graph, &dimvector, 0, IGRAPH_UNDIRECTED,
+                          /* mutual= */ false, &periodic);
+
+    igraph_average_path_length(&graph, NULL, &avg_path_len, NULL,
+                               IGRAPH_UNDIRECTED, /* unconn= */ true);
+    printf("Average path length (lattice):            %g\n", (double) avg_path_len);
+
+    /* Seed the RNG to ensure identical results across runs. */
+    igraph_rng_seed(igraph_rng_default(), 42);
+
+    igraph_vector_int_init(&edges, 20);
+    for (igraph_int_t i = 0; i < igraph_vector_int_size(&edges); i++) {
+        VECTOR(edges)[i] = RNG_INTEGER(0, igraph_vcount(&graph) - 1);
+    }
+
+    igraph_add_edges(&graph, &edges, NULL);
+    igraph_average_path_length(&graph, NULL, &avg_path_len, NULL,
+                               IGRAPH_UNDIRECTED, /* unconn= */ true);
+    printf("Average path length (randomized lattice): %g\n", (double) avg_path_len);
+
+    igraph_vector_bool_destroy(&periodic);
+    igraph_vector_int_destroy(&dimvector);
+    igraph_vector_int_destroy(&edges);
+    igraph_destroy(&graph);
+
+    return 0;
+}
@@ -0,0 +1,53 @@
+#include <igraph.h>
+
+int main(void) {
+    igraph_t graph;
+    igraph_vector_int_t result;
+    igraph_vector_t result_real;
+    igraph_int_t edges_array[] = {
+        0,1, 0,2, 0,3, 0,4, 0,5, 0,6, 0,7, 0,8,
+        0,10, 0,11, 0,12, 0,13, 0,17, 0,19, 0,21, 0,31,
+        1, 2, 1, 3, 1, 7, 1,13, 1,17, 1,19, 1,21, 1,30,
+        2, 3, 2, 7, 2,27, 2,28, 2,32, 2, 9, 2, 8, 2,13,
+        3, 7, 3,12, 3,13, 4, 6, 4,10, 5, 6, 5,10, 5,16,
+        6,16, 8,30, 8,32, 8,33, 9,33, 13,33, 14,32, 14,33,
+        15,32, 15,33, 18,32, 18,33, 19,33, 20,32, 20,33,
+        22,32, 22,33, 23,25, 23,27, 23,32, 23,33, 23,29,
+        24,25, 24,27, 24,31, 25,31, 26,29, 26,33, 27,33,
+        28,31, 28,33, 29,32, 29,33, 30,32, 30,33, 31,32,
+        31,33, 32,33
+    };
+    igraph_vector_int_t edges =
+        igraph_vector_int_view(edges_array, sizeof(edges_array) / sizeof(edges_array[0]));
+
+    /* Initialize the library. */
+    igraph_setup();
+
+    igraph_create(&graph, &edges, 0, IGRAPH_UNDIRECTED);
+
+    igraph_vector_int_init(&result, 0);
+    igraph_vector_init(&result_real, 0);
+
+    igraph_degree(&graph, &result, igraph_vss_all(), IGRAPH_ALL, IGRAPH_LOOPS);
+    printf("Maximum degree is      %10" IGRAPH_PRId ", vertex %2" IGRAPH_PRId ".\n",
+           igraph_vector_int_max(&result),
+           igraph_vector_int_which_max(&result));
+
+    igraph_closeness(&graph, &result_real, NULL, NULL, igraph_vss_all(),
+                     IGRAPH_ALL, /* weights= */ NULL, /* normalized= */ false);
+    printf("Maximum closeness is   %10g, vertex %2" IGRAPH_PRId ".\n",
+           (double) igraph_vector_max(&result_real),
+           igraph_vector_which_max(&result_real));
+
+    igraph_betweenness(&graph, /* weights= */ NULL, &result_real, igraph_vss_all(),
+                       IGRAPH_UNDIRECTED, /* normalized= */ false);
+    printf("Maximum betweenness is %10g, vertex %2" IGRAPH_PRId ".\n",
+           (double) igraph_vector_max(&result_real),
+           igraph_vector_which_max(&result_real));
+
+    igraph_vector_int_destroy(&result);
+    igraph_vector_destroy(&result_real);
+    igraph_destroy(&graph);
+
+    return 0;
+}