Hello, 

I don't get how the weight parameter is used in the shortest_path function when the pred_map is provided.

More precisely the code: https://github.com/count0/graph-tool/blob/master/src/graph_tool/topology/__init__.py#L1368 seems to examine each and any edge when the weight parameter is provided.

What is the point of this behavior ? what do I miss ? 

Best,

f.