Reduce the long compiling time

[xuanzhaogao]

The compiling time is quite long

julia> using OptimalBranching, Graphs

julia> g = random_regular_graph(60, 3)

{60, 90} undirected simple Int64 graph

julia> @time mis_branch_count(g, reducer = MISReducer())
 18.741602 seconds (76.81 M allocations: 3.767 GiB, 4.36% gc time, 99.22% compilation time)
(26, 6)

julia> @time mis_branch_count(g, reducer = MISReducer())
  0.376592 seconds (1.01 M allocations: 49.441 MiB, 74.87% compilation time)
(26, 6)

julia> @time mis_branch_count(g, reducer = MISReducer())
  0.182582 seconds (476.19 k allocations: 23.840 MiB, 10.33% gc time, 34.03% compilation time)
(26, 6)

julia> @time mis_branch_count(g, reducer = MISReducer())
  0.166746 seconds (484.08 k allocations: 24.346 MiB, 44.60% compilation time)
(26, 6)

[GiggleLiu]

The long compiling time is not caused by type instability I think.

[GiggleLiu]

Maybe we should add a mis1 algorithm to enumerate all MISs. It compiles much faster.

[xuanzhaogao]

The long compiling time is not caused by type instability I think.

It seems that after a long run there is no more compiling time.
For example, after solve maybe 100 graphs.