Concatenation in 3 dimension missing

[vchuravy]

This is particular useful in U-Net and related networks.

function cat3d(arrs...)
          H = size(first(arrs), 1)
          W = size(first(arrs), 2)
          C = sum(size(a, 3) for a in arrs)
          T = size(first(arrs), 4)
          
          @assert all(H == size(a, 1) for a in arrs)
          @assert all(W == size(a, 2) for a in arrs)
          @assert all(T == size(a, 4) for a in arrs)
          
          out = Array{Float64}(undef, H, W, C, T)
          curr = 1
          for (i, A) in enumerate(arrs)
            c = size(A, 3)
            r = curr:(curr+c-1)
            out[:, :, r, :] .= A
            curr += c
          end
          out
end

permutedims(reshape(cat1d(permutedims(A, [1, 2, 4, 3]), ...), H, W, T, C), [1, 2, 4, 3])

[ekinakyurek]

First function gives error in Julia 1.0.1.

Below function is working, but I think it is probably slow.

function cat3d2(arrs...)
           parrs = map(x->permutedims(x,(1,2,4,3)), arrs)
           H,W,_,B = size(first(arrs))
           C = sum(size(a, 3) for a in arrs)
           permutedims(reshape(cat1d(parrs...),(H,W,B,C)),(1,2,4,3))
 end

[ekinakyurek]

There is also #319 .

[denizyuret]

I think CuArrays fallbacks fix this in 85c4125