Add graph references

references/igraph-1.0.1/examples/simple/igraph_decompose.c

@@ -0,0 +1,50 @@
+
+#include <igraph.h>
+#include <stdlib.h>
+
+int main(void) {
+
+    igraph_t ring, g, *component;
+    igraph_graph_list_t complist;
+    igraph_int_t i;
+
+    /* Initialize the library. */
+    igraph_setup();
+
+    igraph_graph_list_init(&complist, 0);
+
+    /* A ring, a single component */
+    igraph_ring(&ring, 10, IGRAPH_UNDIRECTED, 0, 1);
+
+    igraph_decompose(&ring, &complist, IGRAPH_WEAK, -1, 0);
+    component = igraph_graph_list_get_ptr(&complist, 0);
+    igraph_write_graph_edgelist(component, stdout);
+    igraph_destroy(&ring);
+    igraph_graph_list_clear(&complist);
+
+    /* Random graph with a giant component */
+    igraph_erdos_renyi_game_gnp(&g, 100, 4.0 / 100, IGRAPH_UNDIRECTED, IGRAPH_SIMPLE_SW, IGRAPH_EDGE_UNLABELED);
+    igraph_decompose(&g, &complist, IGRAPH_WEAK, -1, 20);
+    if (igraph_graph_list_size(&complist) != 1) {
+        return 1;
+    }
+    igraph_destroy(&g);
+    igraph_graph_list_clear(&complist);
+
+    /* A toy graph, three components maximum, with at least 2 vertices each */
+    igraph_small(&g, 0, IGRAPH_DIRECTED,
+                 0, 1, 1, 2, 2, 0,
+                 3, 4, 4, 5, 5, 6,
+                 8, 9, 9, 10,
+                 -1);
+    igraph_decompose(&g, &complist, IGRAPH_WEAK, 3, 2);
+    for (i = 0; i < igraph_graph_list_size(&complist); i++) {
+        component = igraph_graph_list_get_ptr(&complist, i);
+        igraph_write_graph_edgelist(component, stdout);
+    }
+    igraph_destroy(&g);
+
+    igraph_graph_list_destroy(&complist);
+
+    return 0;
+}