Hello Tiago and Tanguy,
I'm following your discussion with great interest as I have a similar
task. I want to convert a multigraph into a simple graph. This works
very nicely with
GraphView(u, efilt=label_parallel_edges(u).fa == 0)
However, removing the parallel edges this way means that the edge
properties of the parallel edges are lost. I have an edge property
called "eqntag" which is a string and I want to concatenate all eqntags
from the parallel edges into the simple graph. I think this is what
Tanguy meant by "edge coalescence". I did not understand how to use
condensation_graph() for this purpose, so I've written my own function:
def remove_parallel_edges_merge_eqntags(g):
# create simple graph g2:
g2 = gt.GraphView(g, efilt=gt.label_parallel_edges(g).fa == 0)
# loop over the remaining edges in the simple graph:
for e in g2.edges():
# create a list with all edges from g that connect the same
# vertices as the current edge in g2:
edgelist = g.edge(e.source(), e.target(), all_edges=True)
# replace eqntag by semicolon-separated merged eqntag:
g2.ep.eqntag[e] = ';'.join([g.ep.eqntag[edge] for edge in edgelist])
return g2
Best regards
Rolf
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