csr assign method not working with undirected graphs

[sebastian.weber@…]

Hi!

Assigning an undirected graph to a csr graph results in an ill defined object. Example:

UndirAdjacencyListGraph adjGraph;

CsrGraph csr;

csr.assign(adjGraph);

This will result in an ill defined csr graph, but with the trick of doubling the edges nominally, everything works as it should:

csr.assign(adjGraph, vertexIndex, num_vertices(adjGraph), 2*num_edges(adjGraph));

works perfeclty and returns a csr graph where the undirected links have been replaced by 2 directed edges appropietly.

Greetings

[Jeremiah Willcock]

(In [55667]) Fixed edge doubling for copying from an undirected graph to a CSR graph; fixes #3357