[igraph] Problem with igraph_simplify() for C

[Quax, Rick]

Dear all,

I try to use the function igraph_simplify() in C to remove self-loops and double edges, but it leaves the network unchanged. It does not matter what I pass as boolean arguments to it (true/false/0/1). I use igraph 0.5.4 and g++ 4.1.2. The following is the relevant piece of code:

-------------------------------------------------------
        igraph_t graph;
        size_t dim = 1, L = 20;
        double p = 0.15;

        int ret = igraph_watts_strogatz_game(&graph, dim, L, nbh, p);

        igraph_write_graph_edgelist(&graph, stdout);

        ret = igraph_simplify(&graph, 1, 1);

        cout << "-----------------------------------\n";

        igraph_write_graph_edgelist(&graph, stdout);
-------------------------------------------------------

The output of this code is the following (i.e., unchanged):

--------------------------------------------------------
0 1
1 2
2 3
3 4
3 19
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12
12 13
13 14
14 15
15 16
16 17
17 18
18 19
-----------------------------------
0 1
1 2
2 3
3 4
3 19
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12
12 13
13 14
14 15
15 16
16 17
17 18
18 19
--------------------------------------------------------

Does anyone have a clue why this happens? In R it does work.

Thank you very much in advance,

Rick