Bug in compress_graph_zero_coeff! #62
Description
The removal of nodes with zero coefficients seems to have a bug (only found for quite large graphs with many zeros). MWE:
Download https://people.kth.se/~eliasj/buggraph2.cgr
julia> graph=import_compgraph("buggraph2.cgr");
julia> @show eval_graph(graph,0.1)
eval_graph(graph, 0.1) = 0.7969737373602765
0.7969737373602765
julia> compress_graph_zero_coeff!(graph)
julia> @show eval_graph(graph,0.1)
eval_graph(graph, 0.1) = 0.9231434910373834
0.9231434910373834