From 4ccbbbb2841d3bfdd36e3557f4c428406eb81b2d Mon Sep 17 00:00:00 2001
From: Mike J Innes <mike.j.innes@gmail.com>
Date: Thu, 8 Jun 2017 10:49:39 +0100
Subject: [PATCH] dup params fix

---
 src/backend/mxnet/graph.jl | 10 +++++-----
 test/backend/mxnet.jl      |  8 ++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/backend/mxnet/graph.jl b/src/backend/mxnet/graph.jl
index 4e3eae01..5e532864 100644
--- a/src/backend/mxnet/graph.jl
+++ b/src/backend/mxnet/graph.jl
@@ -91,9 +91,8 @@ end
 register(ctx::Context, node) = node
 
 function var(ctx::Context, p::Union{Flux.Param{<:AbstractArray},AbstractArray,AlterParam})
-  id = gensym()
-  ctx[:params][id] = p
-  return mx.Variable(id)
+  haskey(ctx[:params], p) && return ctx[:params][p]
+  ctx[:params][p] = mx.Variable(gensym())
 end
 
 var(ctx::Context, x) = x
@@ -110,10 +109,11 @@ graph′(ctx::Context, args...) = @icatch ctx graph(ctx, args...)
 
 function tograph(model, args...; feedforward = false)
   ctx = Context(mux(iline, iconst, ilambda, iargs, ituple, graph′),
-                params = Dict(), stacks = Dict(),
+                params = ObjectIdDict(), stacks = Dict(),
                 feedforward = feedforward)
   out = @ithrow graph(ctx, model, mapt(mx.Variable, args)...)
-  return Graph(args, out, ctx[:params], ctx[:stacks])
+  params = Dict(nodename(v) => p for (p, v) in ctx[:params])
+  return Graph(args, out, params, ctx[:stacks])
 end
 
 # Error Handling
diff --git a/test/backend/mxnet.jl b/test/backend/mxnet.jl
index f0aeb0b7..cad5407e 100644
--- a/test/backend/mxnet.jl
+++ b/test/backend/mxnet.jl
@@ -28,4 +28,12 @@ using Flux: MaxPool
   @test mx.infer_shape(f.arch, data = (20, 20, 5, 1))[2] == [(10, 1)]
 end
 
+@testset "Duplicate parameters" begin
+  a = Affine(10, 10)
+  d = Chain(a, a)
+  m = mxnet(d)
+  m(randn(1, 10))
+  @test length(m.graph.params) == 2
+end
+
 end