functional error in igraph_diameter_dijkstra

[qqchou]

I use igraph-0.5.5-msvc.zip,and find a small bug in function igraph_diameter_dijkstra, which causes function returns wrong result.

In file "spectral_properties.c" ,line 5180,
"for (source=0; source < no_of_nodes; source++)"
where is the loop of "source", variable "nodes_reached" should be initialized to 0 first during each loop, then it can count the number of reached nodes correctly.

In line 5222,
"if (nodes_reached != no_of_nodes && !unconn)"
when unconn is false, the function works improperly.

[qqchou (cece7252)]

sorry,it's file "structural_properties.c"

[Gábor Csárdi (gabor.csardi)]

Yep, it seems that this is a bug, if the graph is directed, but not strongly connected and all vertices are reachable from the first vertex.

[Gábor Csárdi (gabor.csardi)]

I mean, there is a bug if the graph is strongly connected. Anyway, I fixed it in revision 2225, in the 0.6-main tree.

[Gábor Csárdi (gabor.csardi)]

The development of igraph has moved to github, so please do not comment on this bug here. You are of course welcome to comment on github, here:
https://github.com/igraph/igraph/issues/80