tf recurrent models

src/backend/tensorflow/recurrent.jl

@@ -0,0 +1,27 @@
+immutable RModel
+  m::Model
+end
+
+function tf(model::Flux.Unrolled)
+  sess = Session(Graph())
+  input = placeholder(Float32)
+  inputs = TensorFlow.unpack(input, num = model.steps, axis = 1)
+  params, (state, outputs) = tograph(model.graph, inputs...)
+  output = TensorFlow.pack(outputs, axis = 1)
+  run(sess, initialize_all_variables())
+  Model(model, sess, params,
+        [input], [output],
+        [gradients(output, input)]) |> RModel
+end
+
+function batchseq(xs)
+  dims = ndims(xs)-2
+  T = Array{eltype(xs),dims}
+  S = Array{eltype(xs),dims+1}
+  B = Array{eltype(xs),dims+2}
+  Batch{Seq{T,S},B}(xs)
+end
+
+(m::RModel)(x::BatchSeq) = batchseq(rawbatch(m.m(x)))
+
+(m::RModel)(x::Seq) = first(m(batchone(x)))