/*
   igraph library.
   Copyright (C) 2006-2012  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>
#include <math.h>

int main(void) {

    igraph_t g;
    igraph_real_t res;

    /* Initialize the library. */
    igraph_setup();

    /* Trivial cases */

    igraph_ring(&g, 100, IGRAPH_UNDIRECTED, 0, 0);
    igraph_reciprocity(&g, &res, 0, IGRAPH_RECIPROCITY_DEFAULT);
    igraph_destroy(&g);

    if (res != 1) {
        return 1;
    }

    /* Small test graph */

    igraph_small(&g, 0, IGRAPH_DIRECTED,
                 0,  1,  0,  2,  0,  3,  1,  0,  2,  3,  3,  2, -1);

    igraph_reciprocity(&g, &res, 0, IGRAPH_RECIPROCITY_RATIO);
    igraph_destroy(&g);

    if (res != 0.5) {
        fprintf(stderr, "%f != %f\n", res, 0.5);
        return 2;
    }

    igraph_small(&g, 0, IGRAPH_DIRECTED, 0, 1, 1, 2, 2, 1, -1);
    igraph_reciprocity(&g, &res, 0, IGRAPH_RECIPROCITY_DEFAULT);
    igraph_destroy(&g);

    if (fabs(res - 2.0 / 3.0) > 1e-15) {
        fprintf(stderr, "%f != %f\n", res, 2.0 / 3.0);
        return 3;
    }

    return 0;
}
