Support reshape_op double gradient (#20304), test=release/1.6 (#20556)

* support reshape doubel grad, test=develop

* fix reshape double grad, pass converage, test=develop

* fix review, test=develop

paddle/fluid/operators/reshape_op.cc

@@ -363,6 +363,20 @@ class ReshapeGradKernel {
   }
 };
 
+class ReshapeDoubleGradKernel {
+ public:
+  void operator()(const framework::ExecutionContext &ctx) const {
+    auto *dd_x = ctx.Input<framework::Tensor>("DDX");
+    auto *dd_out = ctx.Output<framework::Tensor>("DDOut");
+
+    auto out_dims = dd_out->dims();
+
+    dd_out->mutable_data(ctx.GetPlace(), dd_x->type());
+    framework::TensorCopySync(*dd_x, ctx.GetPlace(), dd_out);
+    dd_out->Resize(out_dims);
+  }
+};
+
 // FIXME(zcd): reshape2 adds an intermediate output(XShape) based on reshape,
 // the XShape is used to carry the shape and lod of X which will be used in
 // reshape_grad, in this way, the framework can reuse the memory of X
@@ -418,6 +432,24 @@ class Reshape2GradMaker : public framework::SingleGradOpDescMaker {
   }
 };
 
+class Reshape2DoubleGradMaker : public framework::SingleGradOpDescMaker {
+ public:
+  using framework::SingleGradOpDescMaker::SingleGradOpDescMaker;
+
+  std::unique_ptr<framework::OpDesc> Apply() const override {
+    auto *grad_op = new framework::OpDesc();
+    grad_op->SetType("reshape2_grad_grad");
+
+    grad_op->SetInput("ShapeTensor", Input("ShapeTensor"));
+    grad_op->SetInput("DOut", Input(framework::GradVarName("Out")));
+    grad_op->SetInput("DDX", OutputGrad(framework::GradVarName("X")));
+
+    grad_op->SetOutput("DDOut", InputGrad(framework::GradVarName("Out")));
+    grad_op->SetAttrMap(Attrs());
+    return std::unique_ptr<framework::OpDesc>(grad_op);
+  }
+};
+
 class Reshape2GradOp : public framework::OperatorWithKernel {
  public:
   Reshape2GradOp(const std::string &type,
@@ -456,10 +488,46 @@ class Reshape2GradOp : public framework::OperatorWithKernel {
   }
 };
 
+class Reshape2DoubleGradOp : public framework::OperatorWithKernel {
+ public:
+  Reshape2DoubleGradOp(const std::string &type,
+                       const framework::VariableNameMap &inputs,
+                       const framework::VariableNameMap &outputs,
+                       const framework::AttributeMap &attrs)
+      : OperatorWithKernel(type, inputs, outputs, attrs) {}
+
+  void InferShape(framework::InferShapeContext *ctx) const override {
+    PADDLE_ENFORCE_EQ(ctx->HasInput("DDX"), true,
+                      "Input(X@GRAD_GRAD) shouldn't be null.");
+
+    if (ctx->HasOutput("DDOut") && ctx->HasInput("DDX")) {
+      ctx->ShareDim("DOut", "DDOut");
+    }
+  }
+
+ protected:
+  framework::OpKernelType GetExpectedKernelType(
+      const framework::ExecutionContext &ctx) const override {
+    return framework::OpKernelType(ctx.Input<framework::Tensor>("DDX")->type(),
+                                   ctx.device_context());
+  }
+
+  framework::OpKernelType GetKernelTypeForVar(
+      const std::string &var_name, const Tensor &tensor,
+      const framework::OpKernelType &expected_kernel_type) const override {
+    if (var_name == "ShapeTensor") {
+      return expected_kernel_type;
+    }
+    return framework::OpKernelType(expected_kernel_type.data_type_,
+                                   tensor.place(), tensor.layout());
+  }
+};
+
 DECLARE_INPLACE_OP_INFERER(ReshapeOpInplaceInToOut, {"X", "Out"});
 DECLARE_INPLACE_OP_INFERER(ReshapeGradInplaceInToOut,
                            {framework::GradVarName("Out"),
                             framework::GradVarName("X")});
+DECLARE_INPLACE_OP_INFERER(ReshapeDoubleGradInplaceInToOut, {"DDX", "DDOut"});
 
 }  // namespace operators
 }  // namespace paddle
@@ -471,6 +539,7 @@ REGISTER_OPERATOR(reshape, ops::ReshapeOp, ops::ReshapeOpMaker,
                   ops::ReshapeOpInplaceInToOut);
 REGISTER_OPERATOR(reshape_grad, ops::ReshapeGradOp,
                   ops::ReshapeGradInplaceInToOut);
+
 REGISTER_OP_CPU_KERNEL_FUNCTOR(reshape, float, ops::ReshapeKernel, double,
                                ops::ReshapeKernel, int, ops::ReshapeKernel,
                                int64_t, ops::ReshapeKernel);
@@ -478,11 +547,13 @@ REGISTER_OP_CPU_KERNEL_FUNCTOR(reshape_grad, float, ops::ReshapeGradKernel,
                                double, ops::ReshapeGradKernel, int,
                                ops::ReshapeGradKernel, int64_t,
                                ops::ReshapeGradKernel);
-
 REGISTER_OPERATOR(reshape2, ops::Reshape2Op, ops::Reshape2OpMaker,
                   ops::Reshape2GradMaker, ops::ReshapeOpInplaceInToOut);
 REGISTER_OPERATOR(reshape2_grad, ops::Reshape2GradOp,
-                  ops::ReshapeGradInplaceInToOut);
+                  ops::Reshape2DoubleGradMaker, ops::ReshapeGradInplaceInToOut);
+REGISTER_OPERATOR(reshape2_grad_grad, ops::Reshape2DoubleGradOp,
+                  ops::ReshapeDoubleGradInplaceInToOut);
+
 REGISTER_OP_CPU_KERNEL_FUNCTOR(reshape2, float, ops::ReshapeKernel, double,
                                ops::ReshapeKernel, int, ops::ReshapeKernel,
                                int64_t, ops::ReshapeKernel);
@@ -490,6 +561,11 @@ REGISTER_OP_CPU_KERNEL_FUNCTOR(reshape2_grad, float, ops::ReshapeGradKernel,
                                double, ops::ReshapeGradKernel, int,
                                ops::ReshapeGradKernel, int64_t,
                                ops::ReshapeGradKernel);
+REGISTER_OP_CPU_KERNEL_FUNCTOR(reshape2_grad_grad, float,
+                               ops::ReshapeDoubleGradKernel, double,
+                               ops::ReshapeDoubleGradKernel, int,
+                               ops::ReshapeDoubleGradKernel, int64_t,
+                               ops::ReshapeDoubleGradKernel);
 
 #ifdef PADDLE_WITH_CUDA
 REGISTER_OP_CUDA_KERNEL_FUNCTOR(reshape, float, ops::ReshapeKernel, double,
@@ -510,4 +586,11 @@ REGISTER_OP_CUDA_KERNEL_FUNCTOR(reshape2_grad, float, ops::ReshapeGradKernel,
                                 ops::ReshapeGradKernel, int64_t,
                                 ops::ReshapeGradKernel, plat::float16,
                                 ops::ReshapeGradKernel);
+
+REGISTER_OP_CUDA_KERNEL_FUNCTOR(reshape2_grad_grad, float,
+                                ops::ReshapeDoubleGradKernel, double,
+                                ops::ReshapeDoubleGradKernel, int,
+                                ops::ReshapeDoubleGradKernel, int64_t,
+                                ops::ReshapeDoubleGradKernel, plat::float16,
+                                ops::ReshapeDoubleGradKernel);
 #endif

python/paddle/fluid/tests/unittests/test_nn_grad.py

@@ -94,5 +94,29 @@ class TestMulDoubleGradCheck(unittest.TestCase):
             self.func(p)
 
 
+class TestReshapeDoubleGradCheck(unittest.TestCase):
+    @prog_scope()
+    def func(self, place):
+        x_shape = [3, 12]
+        new_shape = [4, 9]
+        eps = 0.005
+        dtype = np.float64
+
+        x = layers.data('x', x_shape, False, dtype)
+        x.persistable = True
+        out = layers.reshape(x, new_shape)
+        x_arr = np.random.uniform(-1, 1, x_shape).astype(dtype)
+
+        gradient_checker.double_grad_check(
+            [x], out, x_init=x_arr, place=place, eps=eps)
+
+    def test_grad(self):
+        places = [fluid.CPUPlace()]
+        if core.is_compiled_with_cuda():
+            places.append(fluid.CUDAPlace(0))
+        for p in places:
+            self.func(p)
+
+
 if __name__ == "__main__":
     unittest.main()