compatibility with StaticArrays.jl

[putianyi889]

using StaticArrays

julia> m = SMatrix{2,2}(1, 2, 3, 4)
2×2 SMatrix{2, 2, Int64, 4} with indices SOneTo(2)×SOneTo(2):
 1  3
 2  4

julia> conv(m,m)
ERROR: MethodError: no method matching similar(::SMatrix{2, 2, Float64, 4}, ::Type{Float64}, ::Tuple{UnitRange{Int64}, UnitRange{Int64}})
Closest candidates are:
  similar(::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{N}}, ::Type{ElType}, ::Any) where {N, ElType} at broadcast.jl:212
  similar(::Base.Broadcast.Broadcasted{Base.Broadcast.ArrayConflict}, ::Type{ElType}, ::Any) where ElType at broadcast.jl:217
  similar(::SA, ::Type{T}) where {SA<:StaticArray, T} at C:\Users\pty\.julia\packages\StaticArrays\4WE4t\src\abstractarray.jl:122
  ...
Stacktrace:
 [1] similar(a::SMatrix{2, 2, Float64, 4}, dims::Tuple{UnitRange{Int64}, UnitRange{Int64}})
   @ Base .\abstractarray.jl:795
 [2] _conv_similar(u::SMatrix{2, 2, Float64, 4}, outsize::Tuple{Int64, Int64}, axesu::Tuple{SOneTo{2}, SOneTo{2}}, axesv::Tuple{SOneTo{2}, SOneTo{2}})    
   @ DSP C:\Users\pty\.julia\packages\DSP\wENjI\src\dspbase.jl:657
 [3] _conv_similar(u::SMatrix{2, 2, Float64, 4}, v::SMatrix{2, 2, Float64, 4}, outsize::Tuple{Int64, Int64})
   @ DSP C:\Users\pty\.julia\packages\DSP\wENjI\src\dspbase.jl:664
 [4] _conv(u::SMatrix{2, 2, Float64, 4}, v::SMatrix{2, 2, Float64, 4}, su::Tuple{Int64, Int64}, sv::Tuple{Int64, Int64})
   @ DSP C:\Users\pty\.julia\packages\DSP\wENjI\src\dspbase.jl:675
 [5] conv(u::SMatrix{2, 2, Float64, 4}, v::SMatrix{2, 2, Float64, 4})
   @ DSP C:\Users\pty\.julia\packages\DSP\wENjI\src\dspbase.jl:695
 [6] conv(u::SMatrix{2, 2, Int64, 4}, v::SMatrix{2, 2, Int64, 4})
   @ DSP C:\Users\pty\.julia\packages\DSP\wENjI\src\dspbase.jl:707
 [7] top-level scope
   @ REPL[18]:1

julia> conv(Matrix(m),Matrix(m))
3×3 Matrix{Int64}:
 1   6   9
 4  20  24
 4  16  16

[martinholters]

Hm, yes, would be nice it that just worked. Is there a better alternative to similar that we could use here? Or should StaticArrays allow similar(::StaticArray, ::Type, size::Tuple{Vararg{Integer}}), returning an Array of the requested size?

Even better would this be returning a StaticArray, but that would be quite a bit more involved...

[putianyi889]

A common scenario is a small kernel (3x3 for example) applied to a large matrix. StaticArrays should be a good choice for the kernel. The output doesn't have to be static.