Add LSTM backward implenmentation.

paddle/operators/lstm_op.cc

@@ -21,7 +21,6 @@ class LSTMOp : public framework::OperatorWithKernel {
  public:
   using framework::OperatorWithKernel::OperatorWithKernel;
 
- protected:
   void InferShape(framework::InferShapeContext* ctx) const override {
     PADDLE_ENFORCE(ctx->HasInput("Input"),
                    "Input(Input) of LSTM should not be null.");
@@ -30,8 +29,8 @@ class LSTMOp : public framework::OperatorWithKernel {
     PADDLE_ENFORCE(ctx->HasOutput("Cell"),
                    "Output(Cell) of LSTM should not be null.");
 
-    auto x_dims = ctx->GetInputDim("Input");
-    PADDLE_ENFORCE_EQ(x_dims.size(), 2, "Input(X)'s rank must be 2.");
+    auto in_dims = ctx->GetInputDim("Input");
+    PADDLE_ENFORCE_EQ(in_dims.size(), 2, "Input(X)'s rank must be 2.");
 
     if (ctx->HasInput("H0")) {
       PADDLE_ENFORCE(ctx->HasInput("C0"),
@@ -44,7 +43,7 @@ class LSTMOp : public framework::OperatorWithKernel {
                      "should be the same.");
     }
 
-    int frame_size = x_dims[1] / 4;
+    int frame_size = in_dims[1] / 4;
     auto w_dims = ctx->GetInputDim("Weight");
     PADDLE_ENFORCE_EQ(w_dims.size(), 2,
                       "The rank of Input(Weight) should be 2.");
@@ -71,9 +70,11 @@ class LSTMOp : public framework::OperatorWithKernel {
                         "4 * %d if disable peepholes connection",
                         frame_size);
     }
-    ctx->SetOutputDim("Hidden", {x_dims[0], frame_size});
-    ctx->SetOutputDim("Cell", {x_dims[0], frame_size});
-    ctx->SetOutputDim("BatchGate", x_dims);
+    framework::DDim out_dims({in_dims[0], frame_size});
+    ctx->SetOutputDim("Hidden", out_dims);
+    ctx->SetOutputDim("Cell", out_dims);
+    ctx->SetOutputDim("BatchGate", in_dims);
+    ctx->SetOutputDim("BatchCellPreAct", out_dims);
     ctx->ShareLoD("Input", "Hidden");
     ctx->ShareLoD("Input", "Cell");
   }
@@ -86,7 +87,7 @@ class LSTMOpMaker : public framework::OpProtoAndCheckerMaker {
     AddInput("Input",
              "(LoDTensor) the first input is a LodTensor, which support "
              "variable-time length input sequence. The underlying tensor in "
-             "this LoDTensor is a matrix with shape (T X 4D), where, T is the "
+             "this LoDTensor is a matrix with shape (T X 4D), where T is the "
              "total time steps in this mini-batch, D is the hidden size.");
     AddInput("H0",
              "(Tensor, optional) the initial hidden state is an optional "
@@ -110,21 +111,25 @@ class LSTMOpMaker : public framework::OpProtoAndCheckerMaker {
              "2. `usePeepholes = True` "
              " - The shape is (1 x 7D). "
              " - Bias = {b_c, b_i, b_f, b_o, W_ic, W_fc, W_oc}.");
+    AddOutput("Hidden",
+              "(LoDTensor) the hidden state lod tensor of LSTM operator. "
+              "The shape and lod is the same with the `Input`.");
+    AddOutput("Cell",
+              "(LoDTensor) the cell state lod tensor of LSTM operator. "
+              "The shape and lod is the same with the `Input`.");
     AddOutput("BatchGate",
               "(LoDTensor) This LoDTensor contains input gate, forget gate "
               "and output gate after the nonlinear computation. This "
               "LoDTensor has the same shape with the reorganized input, which "
-              "was also be called batch input. The LoD size is 2. The first "
+              "is also be called batch input. The LoD size is 2. The first "
               "LoD is the batch offsets and the second LoD contains the "
               "indexes, which denote the position of reorganized sequence "
               "in the raw input.")
         .AsIntermediate();
-    AddOutput("Hidden",
-              "(LoDTensor) the hidden state lod tensor of LSTM operator. "
-              "The shape and lod is the same with the `Input`.");
-    AddOutput("Cell",
-              "(LoDTensor) the cell state lod tensor of LSTM operator. "
-              "The shape and lod is the same with the `Input`.");
+    AddOutput("BatchCellPreAct",
+              "(LoDTensor) This LoDTensor is get in the forward and used "
+              "in the backward.")
+        .AsIntermediate();
     AddAttr<bool>("usePeepholes",
                   "(bool, defalut: True) "
                   "whether to enable diagonal/peephole connections.")
@@ -202,15 +207,28 @@ class LSTMGradOp : public framework::OperatorWithKernel {
  public:
   using framework::OperatorWithKernel::OperatorWithKernel;
 
- protected:
   void InferShape(framework::InferShapeContext* ctx) const override {
     PADDLE_ENFORCE(ctx->HasInput(framework::GradVarName("Hidden")),
                    "Input(Hidden@GRAD) should not be null");
     PADDLE_ENFORCE(ctx->HasInput(framework::GradVarName("Cell")),
                    "Input(Cell@GRAD) should not be null");
-    ctx->SetOutputDim(framework::GradVarName("Weight"),
-                      ctx->GetInputDim("Weight"));
-    ctx->SetOutputDim(framework::GradVarName("Bias"), ctx->GetInputDim("Bias"));
+
+    ctx->SetOutputDim(framework::GradVarName("Input"),
+                      ctx->GetInputDim("Input"));
+    if (ctx->HasInput("Weight")) {
+      ctx->SetOutputDim(framework::GradVarName("Weight"),
+                        ctx->GetInputDim("Weight"));
+    }
+    if (ctx->HasInput("Bias")) {
+      ctx->SetOutputDim(framework::GradVarName("Bias"),
+                        ctx->GetInputDim("Bias"));
+    }
+    if (ctx->HasInput("H0")) {
+      ctx->SetOutputDim(framework::GradVarName("H0"), ctx->GetInputDim("H0"));
+    }
+    if (ctx->HasInput("C0")) {
+      ctx->SetOutputDim(framework::GradVarName("C0"), ctx->GetInputDim("C0"));
+    }
   }
 };
 

paddle/operators/lstm_op.h

@@ -21,8 +21,9 @@ limitations under the License. */
 namespace paddle {
 namespace operators {
 
-using framework::LoDTensor;
-using framework::Tensor;
+using LoDTensor = framework::LoDTensor;
+using Tensor = framework::Tensor;
+
 template <typename T, int MajorType = Eigen::RowMajor,
           typename IndexType = Eigen::DenseIndex>
 using EigenMatrix = framework::EigenMatrix<T, MajorType, IndexType>;
@@ -31,15 +32,15 @@ template <typename Place, typename T>
 class LSTMKernel : public framework::OpKernel<T> {
  public:
   void Compute(const framework::ExecutionContext& ctx) const override {
-    auto* input = ctx.Input<framework::LoDTensor>("Input");
-    auto* weight = ctx.Input<framework::Tensor>("Weight");
-    auto* bias = ctx.Input<framework::Tensor>("Bias");
+    auto* input = ctx.Input<LoDTensor>("Input");
+    auto* weight = ctx.Input<Tensor>("Weight");
+    auto* bias = ctx.Input<Tensor>("Bias");
 
-    auto* batch_gate = ctx.Output<framework::LoDTensor>("BatchGate");
+    auto* batch_gate = ctx.Output<LoDTensor>("BatchGate");
     batch_gate->mutable_data<T>(ctx.GetPlace());
-    auto* hidden_out = ctx.Output<framework::LoDTensor>("Hidden");
+    auto* hidden_out = ctx.Output<LoDTensor>("Hidden");
     hidden_out->mutable_data<T>(ctx.GetPlace());
-    auto* cell_out = ctx.Output<framework::LoDTensor>("Cell");
+    auto* cell_out = ctx.Output<LoDTensor>("Cell");
     cell_out->mutable_data<T>(ctx.GetPlace());
 
     // Now the function ShareLoD in InferShape is not implemented.
@@ -49,7 +50,8 @@ class LSTMKernel : public framework::OpKernel<T> {
 
     bool is_reverse = ctx.Attr<bool>("isReverse");
     math::LoDTensor2BatchFunctor<Place, T> to_batch;
-    to_batch(ctx.device_context(), *input, *batch_gate, is_reverse);
+    auto& device_ctx = ctx.device_context();
+    to_batch(device_ctx, *input, *batch_gate, true, is_reverse);
 
     auto in_dims = input->dims();
     int frame_size = static_cast<int>(in_dims[1] / 4);
@@ -69,15 +71,23 @@ class LSTMKernel : public framework::OpKernel<T> {
     }
 
     math::LstmMetaValue<T> lstm_value;
-    T* bias_data = const_cast<T*>(bias->data<T>());
-    // the code style in LstmMetaValue will be updated later.
-    lstm_value.checkIg = bias_data + 4 * frame_size;
-    lstm_value.checkFg = lstm_value.checkIg + frame_size;
-    lstm_value.checkOg = lstm_value.checkFg + frame_size;
+    if (bias) {
+      T* bias_data = const_cast<T*>(bias->data<T>());
+      // the code style in LstmMetaValue will be updated later.
+      lstm_value.checkIg = bias_data + 4 * frame_size;
+      lstm_value.checkFg = lstm_value.checkIg + frame_size;
+      lstm_value.checkOg = lstm_value.checkFg + frame_size;
+    } else {
+      lstm_value.checkIg = nullptr;
+      lstm_value.checkFg = nullptr;
+      lstm_value.checkOg = nullptr;
+    }
     lstm_value.prevStateValue = nullptr;
 
-    framework::LoDTensor batch_out, batch_cell, batch_cell_pre_act;
-    batch_out.mutable_data<T>(dims, ctx.GetPlace());
+    // Use the local variable as here.
+    LoDTensor batch_hidden, batch_cell;
+    auto batch_cell_pre_act = *(ctx.Output<LoDTensor>("BatchCellPreAct"));
+    batch_hidden.mutable_data<T>(dims, ctx.GetPlace());
     batch_cell.mutable_data<T>(dims, ctx.GetPlace());
     batch_cell_pre_act.mutable_data<T>(dims, ctx.GetPlace());
 
@@ -92,7 +102,7 @@ class LSTMKernel : public framework::OpKernel<T> {
       int bend = static_cast<int>(batch_starts[n + 1]);
 
       Tensor gate_t = batch_gate->Slice(bstart, bend);
-      Tensor out_t = batch_out.Slice(bstart, bend);
+      Tensor out_t = batch_hidden.Slice(bstart, bend);
       Tensor cell_t = batch_cell.Slice(bstart, bend);
       Tensor cell_pre_act_t = batch_cell_pre_act.Slice(bstart, bend);
 
@@ -101,9 +111,9 @@ class LSTMKernel : public framework::OpKernel<T> {
       if (n != 0) {
         int pre_h_start = static_cast<int>(batch_starts[n - 1]);
         int pre_h_end = pre_h_start + cur_batch_size;
-        auto pre_hidden_t = batch_out.Slice(pre_h_start, pre_h_end);
-        math::matmul<Place, T>(ctx.device_context(), pre_hidden_t, false,
-                               *weight, false, static_cast<T>(1.0), &gate_t,
+        auto pre_hidden_t = batch_hidden.Slice(pre_h_start, pre_h_end);
+        math::matmul<Place, T>(device_ctx, pre_hidden_t, false, *weight, false,
+                               static_cast<T>(1.0), &gate_t,
                                static_cast<T>(1.0));
       }
       // else if : FIXME support the initial hidden and cell
@@ -112,27 +122,181 @@ class LSTMKernel : public framework::OpKernel<T> {
       lstm_value.outputValue = out_t.data<T>();
       lstm_value.stateValue = cell_t.data<T>();
       lstm_value.stateActiveValue = cell_pre_act_t.data<T>();
-      math::LstmUnitFunctor<Place, T>::compute(ctx.device_context(), lstm_value,
+      math::LstmUnitFunctor<Place, T>::compute(device_ctx, lstm_value,
                                                frame_size, cur_batch_size,
                                                gate_act, cell_act, cand_act);
       lstm_value.prevStateValue = lstm_value.stateValue;
     }
 
     math::Batch2LoDTensorFunctor<Place, T> to_seq;
-    batch_out.set_lod(batch_gate->lod());
+    batch_hidden.set_lod(batch_gate->lod());
     // restore the output hidden in LoDTensor from the batch hidden
-    to_seq(ctx.device_context(), batch_out, *hidden_out);
+    to_seq(device_ctx, batch_hidden, *hidden_out);
 
     batch_cell.set_lod(batch_gate->lod());
     // restore the output cell state in LoDTensor from the batch cell
-    to_seq(ctx.device_context(), batch_cell, *cell_out);
+    to_seq(device_ctx, batch_cell, *cell_out);
   }
 };
 
 template <typename Place, typename T>
 class LSTMGradKernel : public framework::OpKernel<T> {
  public:
-  void Compute(const framework::ExecutionContext& ctx) const override {}
+  void Compute(const framework::ExecutionContext& ctx) const override {
+    auto* input = ctx.Input<LoDTensor>("Input");
+    auto* weight = ctx.Input<Tensor>("Weight");
+    auto* bias = ctx.Input<Tensor>("Bias");
+
+    auto* hidden_out = ctx.Input<LoDTensor>("Hidden");
+    auto* cell_out = ctx.Input<LoDTensor>("Cell");
+
+    auto* batch_gate = ctx.Input<LoDTensor>("BatchGate");
+    auto* batch_cell_pre_act = ctx.Input<LoDTensor>("BatchCellPreAct");
+
+    auto* hidden_g = ctx.Input<LoDTensor>(framework::GradVarName("Hidden"));
+    auto* cell_g = ctx.Input<LoDTensor>(framework::GradVarName("Cell"));
+
+    auto* in_g = ctx.Output<LoDTensor>(framework::GradVarName("Input"));
+    auto* weight_g = ctx.Output<Tensor>(framework::GradVarName("Weight"));
+    auto* bias_g = ctx.Output<Tensor>(framework::GradVarName("Bias"));
+
+    auto& device_ctx = ctx.device_context();
+    if (weight_g) {
+      math::SetConstant<Place, T> zero;
+      zero(device_ctx, weight_g, static_cast<T>(0.0));
+    }
+
+    auto in_dims = input->dims();
+    auto out_dims = hidden_g->dims();
+    int frame_size = static_cast<int>(in_dims[1] / 4);
+    PADDLE_ENFORCE_EQ(frame_size, out_dims[1]);
+
+    math::LstmMetaValue<T> lstm_value;
+    if (bias) {
+      T* bias_data = const_cast<T*>(bias->data<T>());
+      lstm_value.checkIg = bias_data + 4 * frame_size;
+      lstm_value.checkFg = lstm_value.checkIg + frame_size;
+      lstm_value.checkOg = lstm_value.checkFg + frame_size;
+    } else {
+      lstm_value.checkIg = nullptr;
+      lstm_value.checkFg = nullptr;
+      lstm_value.checkOg = nullptr;
+    }
+
+    math::LstmMetaGrad<T> lstm_grad;
+    if (bias && bias_g) {
+      T* bias_g_data = const_cast<T*>(bias_g->mutable_data<T>(ctx.GetPlace()));
+      lstm_grad.checkIgGrad = bias_g_data + 4 * frame_size;
+      lstm_grad.checkFgGrad = lstm_grad.checkIgGrad + frame_size;
+      lstm_grad.checkOgGrad = lstm_grad.checkFgGrad + frame_size;
+    } else {
+      lstm_grad.checkIgGrad = nullptr;
+      lstm_grad.checkFgGrad = nullptr;
+      lstm_grad.checkOgGrad = nullptr;
+    }
+
+    math::LoDTensor2BatchFunctor<Place, T> to_batch;
+
+    // use the local variable as here.
+    LoDTensor batch_hidden;
+    batch_hidden.mutable_data<T>(out_dims, ctx.GetPlace());
+    batch_hidden.set_lod(batch_gate->lod());
+    to_batch(device_ctx, *hidden_out, batch_hidden, false);
+
+    LoDTensor batch_hidden_g;
+    batch_hidden_g.mutable_data<T>(out_dims, ctx.GetPlace());
+    batch_hidden_g.set_lod(batch_gate->lod());
+    to_batch(device_ctx, *hidden_g, batch_hidden_g, false);
+
+    LoDTensor batch_cell;
+    batch_cell.mutable_data<T>(out_dims, ctx.GetPlace());
+    batch_cell.set_lod(batch_gate->lod());
+    to_batch(device_ctx, *cell_out, batch_cell, false);
+
+    LoDTensor batch_cell_g;
+    batch_cell_g.mutable_data<T>(out_dims, ctx.GetPlace());
+    batch_cell_g.set_lod(batch_gate->lod());
+    to_batch(device_ctx, *cell_g, batch_cell_g, false);
+
+    LoDTensor batch_gate_g;
+    batch_gate_g.mutable_data<T>(batch_gate->dims(), ctx.GetPlace());
+    batch_gate_g.set_lod(batch_gate->lod());
+
+    auto gate_act = ctx.Attr<std::string>("gateActivation");
+    auto cell_act = ctx.Attr<std::string>("cellActivation");
+    auto cand_act = ctx.Attr<std::string>("candidateActivation");
+
+    auto batch_starts = batch_gate->lod()[0];
+    size_t num_batch = batch_starts.size() - 1;
+    for (int n = static_cast<int>(num_batch); n >= 0; n--) {
+      int bstart = static_cast<int>(batch_starts[n]);
+      int bend = static_cast<int>(batch_starts[n + 1]);
+
+      Tensor gate = batch_gate->Slice(bstart, bend);
+      Tensor cell = batch_cell.Slice(bstart, bend);
+      Tensor cell_pre_act = batch_cell_pre_act->Slice(bstart, bend);
+      lstm_value.gateValue = gate.data<T>();
+      lstm_value.stateValue = cell.data<T>();
+      lstm_value.stateActiveValue = cell_pre_act.data<T>();
+
+      Tensor out_g = batch_hidden_g.Slice(bstart, bend);
+      Tensor gate_g = batch_gate_g.Slice(bstart, bend);
+      Tensor cell_g = batch_cell_g.Slice(bstart, bend);
+      lstm_grad.stateGrad = cell_g.data<T>();
+      lstm_grad.gateGrad = gate_g.data<T>();
+      lstm_grad.outputGrad = out_g.data<T>();
+
+      if (n != 0) {
+        int bstart_pre = static_cast<int>(batch_starts[n - 1]);
+        Tensor cell_pre = batch_cell.Slice(bstart_pre, bstart);
+        Tensor cell_pre_g = batch_cell_g.Slice(bstart_pre, bstart);
+        lstm_value.prevStateValue = cell_pre.data<T>();
+        lstm_grad.prevStateGrad = cell_pre_g.data<T>();
+      } else {
+        lstm_value.prevStateValue = nullptr;
+        lstm_grad.prevStateGrad = nullptr;
+      }
+
+      int cur_batch_size = bend - bstart;
+      math::LstmUnitGradFunctor<Place, T>::compute(
+          device_ctx, lstm_value, lstm_grad, frame_size, cur_batch_size,
+          gate_act, cell_act, cand_act);
+
+      if (n != 0) {
+        int pre_h_start = static_cast<int>(batch_starts[n - 1]);
+        int pre_h_end = pre_h_start + cur_batch_size;
+        auto pre_hidden_g = batch_hidden_g.Slice(pre_h_start, pre_h_end);
+        math::matmul<Place, T>(device_ctx, gate_g, false, *weight, true,
+                               static_cast<T>(1.0), &pre_hidden_g,
+                               static_cast<T>(1.0));
+        if (weight_g) {
+          /* backward weight */
+          auto pre_hidden = batch_hidden.Slice(pre_h_start, pre_h_end);
+          math::matmul<Place, T>(device_ctx, pre_hidden, true, gate_g, false,
+                                 static_cast<T>(1.0), weight_g,
+                                 static_cast<T>(1.0));
+        }
+      }
+    }
+
+    math::Batch2LoDTensorFunctor<Place, T> to_seq;
+    if (in_g) {
+      /* backward data */
+      to_seq(device_ctx, batch_gate_g, *in_g);
+    }
+    if (bias && bias_g) {
+      /* backward bias */
+      bias_g->mutable_data<T>(ctx.GetPlace());
+      auto bias_g_e = EigenMatrix<T>::From(*bias_g);
+      auto gate_g_e = EigenMatrix<T>::From(batch_gate_g);
+      Eigen::array<int, 2> extents({{1, 4 * frame_size}});
+      Eigen::array<int, 2> offsets({{0, 0}});
+      auto bg = bias_g_e.slice(offsets, extents)
+                    .reshape(Eigen::array<int, 2>({{1, frame_size * 4}}));
+      bg.device(ctx.GetEigenDevice<Place>()) =
+          gate_g_e.sum(Eigen::array<int, 1>({{0}}));
+    }
+  }
 };
 
 }  // namespace operators

paddle/operators/math/sequence2batch.h

@@ -53,7 +53,17 @@ class LoDTensor2BatchFunctor {
  public:
   void operator()(const platform::DeviceContext& context,
                   const framework::LoDTensor& lod_tensor,
-                  framework::LoDTensor& batch, bool is_reverse) const {
+                  framework::LoDTensor& batch, bool is_cal_batch_lod,
+                  bool is_reverse = false) const {
+    if (!is_cal_batch_lod) {
+      auto lods = batch.lod();
+      PADDLE_ENFORCE_EQ(lods.size(), 2UL);
+      PADDLE_ENFORCE_EQ(lods[1].size(), lod_tensor.dims()[1]);
+      CopyMatrixRowsFunctor<Place, T> to_batch;
+      to_batch(context, lod_tensor, lods[1].data(), batch, true);
+      return;
+    }
+
     auto lods = lod_tensor.lod();
     PADDLE_ENFORCE_EQ(lods.size(), 1UL, "Only support one level sequence now.");
     auto lod = lods[0];