Merge pull request #226 from JuliaGPU/tb/sumprod_abs

Properly handle reducing complex numbers with abs.

Author: maleadt

src/mapreduce.jl

@@ -57,6 +57,7 @@ gpu_promote_type(::typeof(Base.add_sum), ::Type{T}) where {T<:Number} = typeof(B
 gpu_promote_type(::typeof(Base.mul_prod), ::Type{T}) where {T<:Number} = typeof(Base.mul_prod(one(T), one(T)))
 gpu_promote_type(::typeof(max), ::Type{T}) where {T<: WidenReduceResult} = T
 gpu_promote_type(::typeof(min), ::Type{T}) where {T<: WidenReduceResult} = T
+gpu_promote_type(::typeof(abs), ::Type{Complex{T}}) where {T} = T
 
 import Base.Broadcast: Broadcasted, ArrayStyle
 const GPUSrcArray = Union{Broadcasted{ArrayStyle{AT}}, GPUArray{T, N}} where {T, N, AT<:GPUArray}
@@ -66,7 +67,7 @@ function Base.mapreduce(f::Function, op::Function, A::GPUSrcArray; dims = :, ini
 end
 
 function mapreduce_impl(f, op, ::NamedTuple{()}, A::GPUSrcArray, ::Colon)
-    OT = gpu_promote_type(op, eltype(A))
+    OT = gpu_promote_type(op, gpu_promote_type(f, eltype(A)))
     v0 = startvalue(op, OT) # TODO do this better
     acc_mapreduce(f, op, v0, A, ())
 end

test/testsuite/mapreduce.jl

@@ -28,6 +28,8 @@ function test_mapreduce(AT)
                     for dims in ((4048,), (1024,1024), (77,), (1923,209))
                         @test compare(sum,  AT, rand(range, dims))
                         @test compare(prod, AT, rand(range, dims))
+                        @test compare(x -> sum(abs, x),  AT, rand(range, dims))
+                        @test compare(x -> prod(abs, x), AT, rand(range, dims))
                         ET <: Complex || @test compare(maximum, AT,rand(range, dims))
                         ET <: Complex || @test compare(minimum, AT,rand(range, dims))
                     end