Merge pull request #368 from JuliaGPU/tb/convert

Simplify conversions.

Author: maleadt

src/host/construction.jl

@@ -1,5 +1,14 @@
 # convenience and indirect construction
 
+# conversions from CPU arrays rely on constructors
+Base.convert(::Type{T}, a::AbstractArray) where {T<:AbstractGPUArray} = a isa T ? a : T(a)
+# TODO: can we implement constructors to and from ::AbstractArray here? by calling the undef
+#       constructor and doing a `copyto!`. this is tricky, due to ambiguities, and no easy
+#       way to go from <:AbstractGPUArray{T,N} to e.g. CuArray{S,N}
+
+
+## convenience constructors
+
 function Base.fill!(A::AnyGPUArray{T}, x) where T
     length(A) == 0 && return A
     gpu_call(A, convert(T, x)) do ctx, a, val
@@ -49,61 +58,3 @@ end
 
 Base.one(x::AbstractGPUMatrix{T}) where {T} = _one(one(T), x)
 Base.oneunit(x::AbstractGPUMatrix{T}) where {T} = _one(oneunit(T), x)
-
-
-## collect & convert
-
-function indexstyle(x::T) where T
-    style = try
-        Base.IndexStyle(x)
-    catch
-        nothing
-    end
-    style
-end
-
-function collect_kernel(ctx::AbstractKernelContext, A, iter, ::IndexCartesian)
-    idx = @cartesianidx(A)
-    @inbounds A[idx...] = iter[idx...]
-    return
-end
-
-function collect_kernel(ctx::AbstractKernelContext, A, iter, ::IndexLinear)
-    idx = linear_index(ctx)
-    @inbounds A[idx] = iter[idx]
-    return
-end
-
-eltype_or(::Type{<: AbstractGPUArray}, or) = or
-eltype_or(::Type{<: AbstractGPUArray{T}}, or) where T = T
-eltype_or(::Type{<: AbstractGPUArray{T, N}}, or) where {T, N} = T
-
-function Base.convert(AT::Type{<: AbstractGPUArray}, iter)
-    isize = Base.IteratorSize(iter)
-    style = indexstyle(iter)
-    ettrait = Base.IteratorEltype(iter)
-    if isbits(iter) && isa(isize, Base.HasShape) && style != nothing && isa(ettrait, Base.HasEltype)
-        # We can collect on the GPU
-        A = similar(AT, eltype_or(AT, eltype(iter)), size(iter))
-        gpu_call(collect_kernel, A, iter, style)
-        A
-    else
-        convert(AT, collect(iter))
-    end
-end
-
-function Base.convert(AT::Type{<: AbstractGPUArray{T, N}}, A::DenseArray{T, N}) where {T, N}
-    copyto!(AT(undef, size(A)), A)
-end
-
-function Base.convert(AT::Type{<: AbstractGPUArray{T1}}, A::DenseArray{T2, N}) where {T1, T2, N}
-    copyto!(similar(AT, size(A)), convert(Array{T1, N}, A))
-end
-
-function Base.convert(AT::Type{<: AbstractGPUArray}, A::DenseArray{T2, N}) where {T2, N}
-    copyto!(similar(AT{T2}, size(A)), A)
-end
-
-function Base.convert(AT::Type{Array{T, N}}, A::AbstractGPUArray{CT, CN}) where {T, N, CT, CN}
-    convert(AT, copyto!(Array{CT, CN}(undef, size(A)), A))
-end