On Mon, Sep 7, 2009 at 2:36 AM, Juanjo Jimenez<
address@hidden> wrote:
> We're working on a SNA project and we've been using igraph library with R.
> Basically, all the programming is done in C.
>
> We added an importer for a graph format defined by us. It's for directed
> graphs with vertex and arc attributes. Apparently, up to this point we had
> no trouble and all works fine. We can access to the vertex and arc
> attributes from the prompt in the R interpreter.
>
> Right now, we're dealing with a C function that needs to query the
> attributes of the vertices and arcs and we are having some problems.
> After building and installing, we import a graph with our importer and then
> when our function is called we get this message from the interpreter:
>
> At cattributes.c:753 : Unknown attribute, Invalid value
>
> In our C function we're using igraph_cattribute_VANV to get all the values
> of all the values of a vertex attribute. Here's where the error comes up.
> Debbuging our code, we ended in this function defined in cattributes.c:
>
> igraph_bool_t igraph_i_cattribute_find(const igraph_vector_ptr_t *ptrvec,
> const char *name, long int *idx) {
> long int i, n=igraph_vector_ptr_size(ptrvec);
> igraph_bool_t l=0;
>
> …
>
> }
>
> The variable n is a negative number after calling igraph_vector_ptr_size
> when should be 2.
>
> From the igraph documentation, we know this:
>
> “… There is an experimental attribute handler that can be used from C code.
> ...”
>
> and were wondering if our problem is related to this experimental state or
> is something else.
>
> Thanks and sorry about my English.
>
>
xwel.importer