Re: [igraph] Re: shortest path length

[Gábor Csárdi]

Yong,

you need to allocate the vector(s) for the result before calling the function. I.e. in this case you need:

igraph_ptr_t results_paths;
igraph_vector_t result_path;

[...]

igraph_vector_init(&result_path, 0);
igraph_vector_ptr_init(&result_paths, 1);
VECTOR(result_paths)[0] = &result_path;

[...]

Btw. igraph_get_shortest_path will just return _one_ shortest path for every vertex included in 'to'.

Gabor

On Thu, Jun 18, 2009 at 10:32 AM, Yong Zou <address@hidden> wrote:

Hi Tamas,

Thanks a lot for helping me. I tried to understand how to write a
correct code. It seems that I always get a
message:"structural_properties.c:873 :Size of the `res' and the `to'
should match".

 igraph_t graph;
 igraph_vector_ptr_t result_paths;
 igraph_vector_t *result_path;
 igraph_integer_t from_node;
 igraph_integer_t to_node;

 igraph_vector_ptr_init(&result_paths, 0);
 from_node = 10;
 to_node = 1000;
 igraph_get_shortest_paths(&graph, &result_paths, from_node,
igraph_vss_1(to_node), IGRAPH_ALL);
 result_path = igraph_vector_ptr_e(&result_paths, 0);   // get the
first path in the result vector
 for (i=0; i<igraph_vector_size(result_path); i++) {
       printf("%ld ", (long)igraph_vector_e(result_path, i));
 }
 printf("\n");
 igraph_vector_destroy(result_path);        // destroy the path
 igraph_vector_ptr_destroy(result_paths);   // free all the pointers
and destroy the pointer list

Best,


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-- 
Gabor Csardi <address@hidden>     UNIL DGM