`get_weigh` returns the transposed results for a SimpleWeighedDiGraph

[jrklasen]

See the following example for SimpleWeightedGraphs v1.3.0:

using SimpleWeightedGraphs
using Graphs

g = SimpleWeightedDiGraph(3)
add_edge!(g, 1, 2, 0.5)
get_weight(g, 1, 2) # gives 0.0 instead of 0.5
get_weight(g, 2, 1) # gives 0.5 instead of 0.0

[simonschoelly]

That sounds rather serious. I can indeed reproduce the error with v1.3.0. I also saw, that we did not have the error with version v1.2.1.

[simonschoelly]

I suspect the issue was introduced in #14.

We probably just have to change

get_weight(g::AbstractSimpleWeightedGraph, u::Integer, v::Integer) = weights(g)[v, u]

into

get_weight(g::AbstractSimpleWeightedGraph, u::Integer, v::Integer) = weights(g)[u, v]

and write some tests to avoid such issues in the future. PRs are welcome :)

[gdalle]

Good catch! I'll take care of it as soon as #38 is merged

[jrklasen]

I'm not familiar with the code base, but be aware that is not happening for other graph types of this package. If they all belong to the same abstract type, this fix wouldn't work.

[simonschoelly]

The only other concrete graph type in this package is the undirected version, so we won't have an issue there.

[gdalle]

Solved by #40