Deleting vertices or edges from an EdgeWeightedDigraph deletes the weights, so does taking a mutable copy.

[markuspf]

I am not sure this is intended.

Creating a digraph with edge weights and removing vertices, edges, or taking a mutable copy makes the resulting grpah not have weights.

gap> d := EdgeWeightedDigraph([[2], [3], [4], []], [[1], [1], [1], []]);
<immutable digraph with 4 vertices, 3 edges>
gap> HasEdgeWeights(d);
true
gap> e := DigraphRemoveVertex(d, 1);
<immutable digraph with 3 vertices, 2 edges>
gap> HasWeights(e);
Error, Variable: 'HasWeights' must have a value
not in any function at *stdin*:19
gap> HasEdgeWeights(e);
false
gap> f := DigraphRemoveEdge(d, 1, 2);
<immutable digraph with 4 vertices, 2 edges>
gap> HasEdgeWeights(f);              
false
gap> g := DigraphMutableCopy(d);
<mutable digraph with 4 vertices, 3 edges>
gap> HasEdgeWeights(g);
false