I've written an implementation of vcat for the special case of mixed
scalar-vector parameters (e.g. vcat(1,[2,3],4)) using generated functions.
I get a speed increase of a factor 70 and memory usage reduction by a
factor 10. It also makes this special case of vcat type stable (e.g. the
inferred type is Array{Int64,1} rather than Any for vcat(1,[2,3],4)). See
https://gist.github.com/afniedermayer/947faadd362778d088d7
I'd like to make a pull request (or at least provide a package that
overloads vcat to start with), but I haven't figured out how to dispatch on
mixed scalar-vector parameters.
Base.vcat{T}(x::Union{T,Array{T,1}}...) = mixed_vcat(x...)
doesn't work, see
https://groups.google.com/forum/#!topic/julia-users/NCfxu7_9VR0
Is there a way to dispatch on mixed scalar-vector parameters (besides
dispatching in the generated function)?
