Function example_1 

pub(crate) fn example_1()

Introduction

A simple test that creates a random graph and computes its diameter and mean degree. It is a translation of the first example from the igraph C library documentation, that can be found in the first lesson.

C code

#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;
}