Row convolution operation.

doc/api/v2/config/layer.rst

@@ -59,6 +59,11 @@ context_projection
 ..  autoclass:: paddle.v2.layer.context_projection
     :noindex:
 
+row_conv
+--------
+..  autoclass:: paddle.v2.layer.row_conv
+    :noindex:
+
 Image Pooling Layer
 ===================
 
@@ -346,6 +351,12 @@ sampling_id
 ..  autoclass:: paddle.v2.layer.sampling_id
     :noindex:
 
+multiplex
+---------
+..  autoclass:: paddle.v2.layer.multiplex
+    :noindex:
+
+
 Slicing and Joining Layers
 ==========================
 

paddle/function/CMakeLists.txt

@@ -28,6 +28,7 @@ if(WITH_TESTING)
     add_simple_unittest(PadOpTest)
     add_simple_unittest(MulOpTest)
     add_simple_unittest(CosSimOpTest)
+    add_simple_unittest(RowConvOpTest)
 endif()
 endif()
 

paddle/function/RowConvOp.cpp

@@ -0,0 +1,225 @@
+/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#include "RowConvOp.h"
+#include <iostream>
+#include "paddle/math/Vector.h"
+
+namespace paddle {
+
+template <>
+void RowConv<DEVICE_TYPE_CPU>(CpuMatrix& out,
+                              const CpuMatrix& in,
+                              const CpuMatrix& filter,
+                              const CpuIVector& seq) {
+  const int* starts = seq.getData();
+  const size_t numSeq = seq.getSize() - 1;
+  const size_t contextLength = filter.getHeight();
+  for (size_t i = 0; i < numSeq; ++i) {
+    size_t begin = starts[i];
+    size_t end = starts[i + 1];
+    for (size_t j = begin; j < end; ++j) {
+      MatrixPtr x;
+      MatrixPtr w;
+      if ((j + contextLength) < end) {
+        x = (const_cast<CpuMatrix&>(in)).subMatrix(j, contextLength);
+        w = (const_cast<CpuMatrix&>(filter)).subMatrix(0, contextLength);
+      } else {
+        x = (const_cast<CpuMatrix&>(in)).subMatrix(j, end - j);
+        w = (const_cast<CpuMatrix&>(filter)).subMatrix(0, end - j);
+      }
+      MatrixPtr y = out.subMatrix(j, 1);
+      y->addDotMulVMM(*x, *w);
+    }
+  }
+}
+
+template <>
+void RowConvGrad<DEVICE_TYPE_CPU>(const CpuMatrix& outG,
+                                  const CpuMatrix& in,
+                                  const CpuMatrix& filter,
+                                  CpuMatrix& inG,
+                                  CpuMatrix& filterG,
+                                  const CpuIVector& seq) {
+  // gradient w.r.t filter
+  const int* starts = seq.getData();
+  const size_t numSeq = seq.getSize() - 1;
+  const size_t contextLength = filter.getHeight();
+  if (filterG) {
+    for (size_t i = 0; i < numSeq; ++i) {
+      size_t begin = starts[i];
+      size_t end = starts[i + 1];
+      size_t steps = end - begin;
+      for (size_t j = 0; j < contextLength && (begin + j) < end; ++j) {
+        MatrixPtr x =
+            (const_cast<CpuMatrix&>(in)).subMatrix(begin + j, steps - j);
+        MatrixPtr dy =
+            (const_cast<CpuMatrix&>(outG)).subMatrix(begin, steps - j);
+        MatrixPtr dw = filterG.subMatrix(j, 1);
+        dw->addDotMulVMM(*dy, *x);
+      }
+    }
+  }
+
+  // gradient w.r.t input feature
+  if (inG) {
+    for (size_t i = 0; i < numSeq; ++i) {
+      size_t begin = starts[i];
+      size_t end = starts[i + 1];
+      size_t steps = end - begin;
+      for (size_t j = 0; j < steps; ++j) {
+        MatrixPtr dx = inG.subMatrix(begin + j, 1);
+        for (size_t t = 0; t < contextLength; ++t) {
+          if (int(j - t) >= 0) {
+            MatrixPtr dy =
+                (const_cast<CpuMatrix&>(outG)).subMatrix(begin + j - t, 1);
+            MatrixPtr w = (const_cast<CpuMatrix&>(filter)).subMatrix(t, 1);
+            dx->addDotMul(*dy, *w, 1.0, 1.0);
+          }
+        }
+      }
+    }
+  }
+}
+
+/**
+ * \brief The row convolution is called lookahead convolution. It is firstly
+ * introduced in deep-speech2 system. The bidirectional RNN that learns
+ * representation for a sequence by performing a forward and a backward pass
+ * through the entire sequence. However, unlike unidirectional RNNs,
+ * bidirectional RNNs are challenging to deploy in an online and low-latency
+ * setting. The lookahead convolution incorporates information from future
+ * subsequences in a computationally efficient manner to improve unidirectional
+ * recurrent neural networks.
+ *
+ * The connection of row convolution is different form the 1D sequence
+ * convolution. Assumed that, the future context-length is k, that is to say,
+ * it can get the output at timestep t by using the the input feature from t-th
+ * timestep to (t+k)-th timestep. Assumed that the hidden dim of input
+ * activations are d, the activations r_t for the new layer at time-step t are:
+ *
+ *
+ *            -- k + 1
+ *  r(t,i) =  >       W(i,j) * h(t+j-1, i),  for (1 <= i <= d)
+ *            -- j = 1
+ *
+ *
+ * The weight shape is: (k + 1) x d
+ * Function Arguments:
+ *
+ * \param inputs[0]  The input activations.
+ * \param inputs[0]  The filter (or weight) and shape is (k+1) x d.
+ * \param outputs[1] The output activations.
+ *
+ * [1] Dario Amodei, etc. Deep Speech 2 : End-to-End Speech Recognition in
+ * English
+ *     and Mandarin. https://arxiv.org/abs/1512.02595
+ */
+
+template <DeviceType Device>
+class RowConvFunc : public FunctionBase {
+public:
+  void init(const FuncConfig& config) override {}
+
+  void calc(const BufferArgs& inputs, const BufferArgs& outputs) override {
+    // check
+    CHECK_EQ(2UL, inputs.size());
+    CHECK_EQ(1UL, outputs.size());
+    // TODO(qingqing): support ASSIGN_TO.
+    CHECK_EQ(outputs[0].getArgType(), ADD_TO);
+    CHECK(inputs[0].isSequenceArg() && outputs[0].isSequenceArg())
+        << "SequenceArg required here.";
+    const auto in = dynamic_cast<const SequenceArg&>(inputs[0]);
+    auto out = dynamic_cast<const SequenceArg&>(outputs[0]);
+    auto w = inputs[1];
+    CHECK(in.data() && out.data() && in.getSequenceId().data());
+    CHECK_EQ(in.shape().ndims(), 2UL);
+    CHECK(in.shape() == out.shape());
+    CHECK_EQ(w.shape()[1], in.shape()[1]);
+
+    auto outMat = out.matrix<Device>();
+    const auto inMat = in.matrix<Device>();
+    const auto wMat = w.matrix<Device>();
+    const auto seqId = in.getSequenceId().vector<int, Device>();
+
+    RowConv<Device>(outMat, inMat, wMat, seqId);
+  }
+};
+
+/**
+ * \brief The backward of row convolution function. This function calculated
+ * the gradient w.r.t filter and the gradient w.r.t input activations(or data).
+ *
+ * Argument in this Function:
+ *
+ * \param inputs[0]  The gradient w.r.t output activations.
+ * \param inputs[1]  The input activations.
+ * \param inputs[2]  The filter (or weight) and shape is (k+1) x d.
+ * \param outputs[0] The gradient w.r.t input activations.
+ * \param outputs[1] The gradient w.r.r filter.
+ *
+ * Abbreviation:
+ * w.r.t: with respect to.
+ */
+
+template <DeviceType Device>
+class RowConvGradFunc : public FunctionBase {
+  // TODO(qingqing): split into RowConvDataFunc and RowConvWeightFunc
+public:
+  void init(const FuncConfig& config) override {}
+
+  void calc(const BufferArgs& inputs, const BufferArgs& outputs) override {
+    // check
+    CHECK_EQ(3UL, inputs.size());
+    CHECK_EQ(2UL, outputs.size());
+    CHECK_EQ(outputs[0].getArgType(), ADD_TO);
+    CHECK_EQ(outputs[1].getArgType(), ADD_TO);
+    CHECK(inputs[0].isSequenceArg() && inputs[1].isSequenceArg() &&
+          outputs[0].isSequenceArg())
+        << "SequenceArg required here.";
+
+    const auto outGrad = dynamic_cast<const SequenceArg&>(inputs[0]);
+    const auto in = dynamic_cast<const SequenceArg&>(inputs[1]);
+    const auto w = inputs[2];
+    auto inGrad = dynamic_cast<const SequenceArg&>(outputs[0]);
+    auto wGrad = outputs[1];
+
+    CHECK_EQ(in.shape().ndims(), 2UL);
+    CHECK(in.shape() == inGrad.shape());
+    CHECK(in.shape() == outGrad.shape());
+    CHECK_EQ(wGrad.shape()[1], in.shape()[1]);
+
+    const auto outGMat = outGrad.matrix<Device>();
+    const auto inMat = in.matrix<Device>();
+    const auto wMat = w.matrix<Device>();
+    auto inGMat = inGrad.data()
+                      ? inGrad.matrix<Device>()
+                      : typename Tensor<real, Device>::Matrix(nullptr, 0, 0);
+    auto wGMat = wGrad.data()
+                     ? wGrad.matrix<Device>()
+                     : typename Tensor<real, Device>::Matrix(nullptr, 0, 0);
+    const auto seqId = in.getSequenceId().vector<int, Device>();
+
+    RowConvGrad<Device>(outGMat, inMat, wMat, inGMat, wGMat, seqId);
+  }
+};
+
+REGISTER_TYPED_FUNC(RowConv, CPU, RowConvFunc);
+REGISTER_TYPED_FUNC(RowConvGrad, CPU, RowConvGradFunc);
+#ifndef PADDLE_ONLY_CPU
+REGISTER_TYPED_FUNC(RowConv, GPU, RowConvFunc);
+REGISTER_TYPED_FUNC(RowConvGrad, GPU, RowConvGradFunc);
+#endif
+
+}  // namespace paddle

paddle/function/RowConvOp.h

@@ -0,0 +1,56 @@
+/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#pragma once
+
+#include "Function.h"
+
+namespace paddle {
+
+/**
+ * \brief The forward of row convolution.
+ *
+ * \param[out] out      The output data and shape is h x d. h is the sum of
+ *                      time steps of all samples in one mini-batch.
+ * \param[in]  in       The input data and shape is h x d.
+ * \param[in]  filter   The filter and shape is k x d. The lookahead step
+ *                      number plus one equals k.
+ * \param[in]  seq      The sequence start positions.
+ *
+ */
+template <DeviceType DType>
+void RowConv(typename Tensor<real, DType>::Matrix& out,
+             const typename Tensor<real, DType>::Matrix& in,
+             const typename Tensor<real, DType>::Matrix& filter,
+             const typename Tensor<int, DType>::Vector& seq);
+
+/**
+ * \brief The backward of row convolution.
+ *
+ * \param[in]  outG     The gradient w.r.t output data.
+ * \param[in]  in       The input data.
+ * \param[in]  filter   The filter.
+ * \param[out] inG      The gradient w.r.t input data.
+ * \param[out] filterG  The gradient w.r.t filter.
+ * \param[in]  seq      The sequence start positions.
+ *
+ */
+template <DeviceType DType>
+void RowConvGrad(const typename Tensor<real, DType>::Matrix& outG,
+                 const typename Tensor<real, DType>::Matrix& in,
+                 const typename Tensor<real, DType>::Matrix& filter,
+                 typename Tensor<real, DType>::Matrix& inG,
+                 typename Tensor<real, DType>::Matrix& filterG,
+                 const typename Tensor<int, DType>::Vector& seq);
+}  // namespace paddle