Make v and hcat with numbers work. (#379)

Author: maleadt

src/host/base.jl

@@ -50,3 +50,13 @@ function PermutedDimsArrays._copy!(dest::PermutedDimsArray{T,N,<:Any,<:Any,<:Abs
     dest .= src
     dest
 end
+
+## concatenation
+
+# hacky overloads to make simple vcat and hcat with numbers work as expected.
+# we can't really make this work in general without Base providing
+# a dispatch mechanism for output container type.
+@inline Base.vcat(a::Number, b::AbstractGPUArray) =
+    vcat(fill!(similar(b, typeof(a), (1,size(b)[2:end]...)), a), b)
+@inline Base.hcat(a::Number, b::AbstractGPUArray) =
+    hcat(fill!(similar(b, typeof(a), (size(b)[1:end-1]...,1)), a), b)

test/testsuite/base.jl

@@ -115,13 +115,24 @@ end
         end
     end
 
-    @testset "vcat + hcat" begin
-        @test compare(vcat, AT, fill(0f0, (10, 10)), rand(Float32, 20, 10))
-        @test compare(hcat, AT, fill(0f0, (10, 10)), rand(Float32, 10, 10))
-
-        @test compare(hcat, AT, rand(Float32, 3, 3), rand(Float32, 3, 3))
-        @test compare(vcat, AT, rand(Float32, 3, 3), rand(Float32, 3, 3))
-        @test compare((a,b) -> cat(a, b; dims=4), AT, rand(Float32, 3, 4), rand(Float32, 3, 4))
+    @testset "cat" begin
+        @test compare(hcat, AT, rand(3), rand(3))
+        @test compare(hcat, AT, rand(), rand(1, 3))
+        @test compare(hcat, AT, rand(1, 3), rand())
+        @test compare(hcat, AT, rand(3), rand(3, 3))
+        @test compare(hcat, AT, rand(3, 3), rand(3))
+        @test compare(hcat, AT, rand(3, 3), rand(3, 3))
+        #@test compare(hcat, AT, rand(), rand(3, 3))
+        #@test compare(hcat, AT, rand(3, 3), rand())
+
+        @test compare(vcat, AT, rand(3), rand(3))
+        @test compare(vcat, AT, rand(3, 3), rand(3, 3))
+        @test compare(vcat, AT, rand(), rand(3))
+        @test compare(vcat, AT, rand(3), rand())
+        @test compare(vcat, AT, rand(), rand(3, 3))
+        #@test compare(vcat, AT, rand(3, 3), rand())
+
+        @test compare((a,b) -> cat(a, b; dims=4), AT, rand(3, 4), rand(3, 4))
     end
 
     @testset "reshape" begin