[igraph] invalid node ID after adding (and try to connect) the 999th node

[Elena Tea Russo]

Hi all,

I am working on a language network builded by adding up nodes (and the edges) with a C program reading a .txt file. (I am usin the C libraries).

I start with a 1 node graph, then I add a new node and connect it with the previous one – and so on, connecting nodes by considering the text as a co-occurrence written language newtork.

 Everything works with small texts; but with big texts, when I reach the 999th node i get an error: when the program try to connect this node to another (existing) one by building a new edge, it gives me back a "unvalid id node" error.

I tryied then to build a 10.000 nodes graph and just connect nodes following the same criteria, with the difference that now the nodes are pre-existing: nothing, the error on the 999th node edge's continue to appear.

Is it a limit of igraph? Or maybe there is something I am missing?

this are the parts of the programs which works on the graph:

[...]

igraph_i_set_attribute_table(&igraph_cattribute_table);

/*variables*/

igraph_real_t reale1, reale2, reale3;

igraph_integer_t old, now; old=0;

igraph_t grafo;

igraph_vector_t v1; igraph_vector_init(&v1, 2);

igraph_vector_t nowed, olded; igraph_vector_init(&olded, 2); igraph_vector_init(&nowed, 2);

igraph_strvector_t names; igraph_strvector_init(&names, 1); 

[...]

/*empty new graph*/

VECTOR(v1)[0]=0;

VECTOR(v1)[1]=0;

igraph_create(&grafo, &v1, 2,0);

/*build graph*/

[...]

if(checkmatch==1) {now=match; igraph_add_edge(&grafo,old,now);}

if(checkmatch==0) {

[...]

/*igraph_add_vertices(&grafo, 1, 0);*/

igraph_strvector_add(&names, " ");

igraph_strvector_set2(&names,lastregword,temp1,cont);

igraph_add_edge(&grafo,old,now);

[...]

free(temp1);

++lastregword;

}

[...]

SETVASV(&grafo, "id", &names);

igraph_write_graph_pajek(&grafo, output);

/*strvector_print(&names);*/

n=igraph_vcount(&grafo);

m=igraph_strvector_size(&names);

printf("n=%i , m(size)=%i, lastregword= %i \n", n,m,  lastregword);

igraph_strvector_destroy(&names);

igraph_destroy(&grafo);

fclose(input);

fclose(output);

free(temp1);

return 0;

}

Thank you for reading me

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Elena Tea RUSSO - address@hidden

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