Add graph references

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

@@ -0,0 +1,175 @@
+/*
+   igraph library.
+   Copyright (C) 2009-2012  Gabor Csardi <csardi.gabor@gmail.com>
+   334 Harvard st, Cambridge MA, 02139 USA
+
+   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 <igraph.h>
+
+int main(void) {
+
+    igraph_sparsemat_t A, B, C, D;
+    igraph_t G, H;
+    igraph_vector_t vect;
+    igraph_int_t i;
+
+    /* Initialize the library. */
+    igraph_setup();
+
+    /* Create, compress, destroy */
+    igraph_sparsemat_init(&A, 100, 20, 50);
+    igraph_sparsemat_compress(&A, &B);
+    igraph_sparsemat_destroy(&B);
+    igraph_sparsemat_destroy(&A);
+
+    /* Convert a ring graph to a matrix, print it, compress, print again */
+#define VC 10
+    igraph_sparsemat_init(&A, 1, 1, 0);
+    igraph_ring(&G, VC, /*directed=*/ 0, /*mutual=*/ 0, /*circular=*/ 1);
+    igraph_get_adjacency_sparse(&G, &A, IGRAPH_GET_ADJACENCY_BOTH, NULL, IGRAPH_LOOPS_ONCE);
+    igraph_destroy(&G);
+
+    igraph_sparsemat_compress(&A, &B);
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_print(&B, stdout);
+
+    /* Basic query, nrow, ncol, type, is_triplet, is_cc */
+    if (igraph_sparsemat_nrow(&A) != VC ||
+        igraph_sparsemat_ncol(&A) != VC ||
+        igraph_sparsemat_nrow(&B) != VC ||
+        igraph_sparsemat_ncol(&B) != VC) {
+        return 1;
+    }
+    if (!igraph_sparsemat_is_triplet(&A)) {
+        return 2;
+    }
+    if (!igraph_sparsemat_is_cc(&B))      {
+        return 3;
+    }
+    if (igraph_sparsemat_type(&A) != IGRAPH_SPARSEMAT_TRIPLET) {
+        return 4;
+    }
+    if (igraph_sparsemat_type(&B) != IGRAPH_SPARSEMAT_CC)      {
+        return 5;
+    }
+
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+#undef VC
+
+    printf("------------------------\n");
+
+    /* Create unit matrices */
+    igraph_sparsemat_init_eye(&A, /*n=*/ 5, /*nzmax=*/ 5, /*value=*/ 1.0, /*compress=*/ 0);
+    igraph_sparsemat_init_eye(&B, /*n=*/ 5, /*nzmax=*/ 5, /*value=*/ 1.0, /*compress=*/ 1);
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+
+    printf("------------------------\n");
+
+    /* Create diagonal matrices */
+    igraph_vector_init(&vect, 5);
+    for (i = 0; i < 5; i++) {
+        VECTOR(vect)[i] = i;
+    }
+    igraph_sparsemat_init_diag(&A, /*nzmax=*/ 5, /*values=*/ &vect, /*compress=*/ 0);
+    igraph_sparsemat_init_diag(&B, /*nzmax=*/ 5, /*values=*/ &vect, /*compress=*/ 1);
+    igraph_vector_destroy(&vect);
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+
+    printf("------------------------\n");
+
+    /* Transpose matrices */
+    igraph_sparsemat_init(&A, 1, 1, 0);
+    igraph_kary_tree(&G, 10, /*children=*/ 2, IGRAPH_TREE_OUT);
+    igraph_get_adjacency_sparse(&G, &A, IGRAPH_GET_ADJACENCY_BOTH, NULL, IGRAPH_LOOPS_ONCE);
+    igraph_destroy(&G);
+    igraph_sparsemat_compress(&A, &B);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_transpose(&B, &C);
+    igraph_sparsemat_print(&C, stdout);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+    igraph_sparsemat_destroy(&C);
+
+    printf("------------------------\n");
+
+    /* Add duplicate elements */
+    igraph_sparsemat_init(&A, 10, 10, /*nzmax=*/ 20);
+    for (i = 1; i < 10; i++) {
+        igraph_sparsemat_entry(&A, 0, i, 1.0);
+    }
+    for (i = 1; i < 10; i++) {
+        igraph_sparsemat_entry(&A, 0, i, 1.0);
+    }
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_compress(&A, &B);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_dupl(&B);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+
+    printf("------------------------\n");
+
+    /* Drop zero elements */
+    igraph_sparsemat_init(&A, 10, 10, /*nzmax=*/ 20);
+    igraph_sparsemat_entry(&A, 7, 3, 0.0);
+    for (i = 1; i < 10; i++) {
+        igraph_sparsemat_entry(&A, 0, i, 1.0);
+        igraph_sparsemat_entry(&A, 0, i, 0.0);
+    }
+    igraph_sparsemat_entry(&A, 0, 0, 0.0);
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_compress(&A, &B);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_dropzeros(&B);
+    igraph_sparsemat_print(&B, stdout);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+
+    printf("------------------------\n");
+
+    /* Add two matrices */
+
+    igraph_sparsemat_init(&A, 1, 1, 0);
+    igraph_sparsemat_init(&B, 1, 1, 0);
+    igraph_star(&G, 10, IGRAPH_STAR_OUT, /*center=*/ 0);
+    igraph_ring(&H, 10, /*directed=*/ 0, /*mutual=*/ 0, /*circular=*/ 1);
+    igraph_get_adjacency_sparse(&G, &A, IGRAPH_GET_ADJACENCY_BOTH, NULL, IGRAPH_LOOPS_ONCE);
+    igraph_get_adjacency_sparse(&H, &B, IGRAPH_GET_ADJACENCY_BOTH, NULL, IGRAPH_LOOPS_ONCE);
+    igraph_destroy(&G);
+    igraph_destroy(&H);
+    igraph_sparsemat_compress(&A, &C);
+    igraph_sparsemat_compress(&B, &D);
+    igraph_sparsemat_destroy(&A);
+    igraph_sparsemat_destroy(&B);
+    igraph_sparsemat_add(&C, &D, /*alpha=*/ 1.0, /*beta=*/ 2.0, &A);
+    igraph_sparsemat_destroy(&C);
+    igraph_sparsemat_destroy(&D);
+    igraph_sparsemat_print(&A, stdout);
+    igraph_sparsemat_destroy(&A);
+
+    return 0;
+}