From d35191595d6fbb6680c5dd46a9bb8a4e4d0fba01 Mon Sep 17 00:00:00 2001
From: Mike J Innes <mike.j.innes@gmail.com>
Date: Wed, 8 Mar 2017 01:19:51 +0000
Subject: [PATCH] mxarray

---
 src/backend/mxnet/mxarray.jl | 39 ++++++++++++++++++++++++++++++++++++
 src/backend/mxnet/mxnet.jl   |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 src/backend/mxnet/mxarray.jl

diff --git a/src/backend/mxnet/mxarray.jl b/src/backend/mxnet/mxarray.jl
new file mode 100644
index 00000000..a7941ac7
--- /dev/null
+++ b/src/backend/mxnet/mxarray.jl
@@ -0,0 +1,39 @@
+using MXNet
+
+# NDArray is row-major so by default all dimensions are reversed in MXNet.
+# MXArray tranposes when loading/storing to fix this.
+
+reversedims!(dest, xs) = permutedims!(dest, xs, ndims(xs):-1:1)
+
+immutable MXArray{N}
+  data::mx.NDArray
+  scratch::Array{Float32,N}
+end
+
+MXArray{T}(data::mx.NDArray, scratch::Array{Float32, T}) = MXArray{T}(data, scratch)
+
+MXArray(data::mx.NDArray) = MXArray(data, Array{Float32}(size(data)))
+
+MXArray(dims::Integer...) = MXArray(mx.zeros(reverse(dims)))
+
+Base.size(xs::MXArray) = reverse(size(xs.data))
+
+function Base.copy!(mx::MXArray, xs::AbstractArray)
+  @assert size(mx) == size(xs)
+  reversedims!(mx.scratch, xs)
+  copy!(mx.data, mx.scratch)
+  return mx
+end
+
+function Base.copy!(xs::AbstractArray, mx::MXArray)
+  @assert size(xs) == size(mx)
+  copy!(mx.scratch, mx.data)
+  reversedims!(xs, mx.scratch)
+end
+
+Base.copy(mx::MXArray) = copy!(Array{Float32}(size(mx)), mx)
+
+function MXArray(xs::AbstractArray)
+  mx = MXArray(size(xs)...)
+  copy!(mx, xs)
+end
diff --git a/src/backend/mxnet/mxnet.jl b/src/backend/mxnet/mxnet.jl
index 8f8be89a..fb9db1dd 100644
--- a/src/backend/mxnet/mxnet.jl
+++ b/src/backend/mxnet/mxnet.jl
@@ -4,6 +4,7 @@ using MXNet, DataFlow, ..Flux
 
 export mxnet
 
+include("mxarray.jl")
 include("graph.jl")
 include("model.jl")