Fix mean with dimension argument

Author: andreasnoack

src/DistributedArrays.jl

@@ -5,6 +5,7 @@ module DistributedArrays
 using Distributed
 using Serialization
 using LinearAlgebra
+using Statistics
 
 import Base: +, -, *, div, mod, rem, &, |, xor
 import Base.Callable

src/mapreduce.jl

@@ -116,6 +116,7 @@ function Base.mapreducedim!(f, op, R::DArray, A::DArray)
     return mapreducedim_between!(identity, op, R, B, region)
 end
 
+## Some special cases
 function Base._all(f, A::DArray, ::Colon)
     B = asyncmap(procs(A)) do p
         remotecall_fetch(p) do
@@ -159,6 +160,8 @@ function Base.extrema(d::DArray)
     return reduce((t,s) -> (min(t[1], s[1]), max(t[2], s[2])), r)
 end
 
+Statistics._mean(A::DArray, region) = sum(A, dims = region) ./ prod((size(A, i) for i in region))
+
 # Unary vector functions
 (-)(D::DArray) = map(-, D)
 

test/darray.jl

@@ -315,7 +315,7 @@ check_leaks()
 @testset "test statistical functions on DArrays" begin
     dims = (20,20,20)
     DA = drandn(dims)
-    A = convert(Array, DA)
+    A = Array(DA)
 
     @testset "test $f for dimension $dms" for f in (mean, ), dms in (1, 2, 3, (1,2), (1,3), (2,3), (1,2,3))
         # std is pending implementation