Add pure fp16 training with master weights. (#27712)

* add the weight decay func for the momentum op

* Add the multi_precision function in Momentum Optimizer.

* Make sure that the initial value of master weights are same with the fp16 weights.

* add static loss scaling.

* add the rescale_grad function in the pure fp16 training.

* use the original momentum updating method.

* Polish some codes, such as variable names.

* add docstring for apis.

* update the var creation details of _create_master_weight.

* not modify codes about imperative momentum updating.

* Fix the error of test_dist_sparse_tensor_load_momentum UT.

* add unit test for multi precision fp16 training.

* add more unit tests for CI.

* Use lower threshold values for allclose comparing in test_multi_precision_fp16_train UT.

* For CI Coverage Checking.

paddle/fluid/operators/optimizers/momentum_op.cc

@@ -49,13 +49,17 @@ void MomentumOpMaker::Make() {
   AddInput("LearningRate",
            "(Tensor, default Tensor<float>) "
            "Input learning rate");
-
+  AddInput("MasterParam", "FP32 master weight for AMP.").AsDispensable();
   AddOutput("ParamOut",
             "(Tensor) This output is updated parameter. "
             "It shared memory with Input(Param).");
   AddOutput("VelocityOut",
             "(Tensor) This output is updated velocity. "
             "It shared memory with Input(Velocity).");
+  AddOutput("MasterParamOut",
+            "The updated FP32 master weight for AMP. "
+            "It shared memory with Input(MasterParam).")
+      .AsDispensable();
 
   AddAttr<float>("mu", "(float) Momentum coefficient");
   AddAttr<bool>("use_nesterov",
@@ -67,7 +71,17 @@ void MomentumOpMaker::Make() {
       "(string) regularization_method, right now only support l2decay or none")
       .SetDefault("");
   AddAttr<float>("regularization_coeff", "(float) regularization_coeff")
-      .SetDefault(0);
+      .SetDefault(0.0f);
+  AddAttr<bool>("multi_precision",
+                "(bool, default false) "
+                "Whether to use multi-precision during weight updating.")
+      .SetDefault(false);
+  AddAttr<float>(
+      "rescale_grad",
+      "(float, default 1.0) Multiply the gradient with `rescale_grad`"
+      "before updating. Often choose to be `1.0/batch_size`.")
+      .SetDefault(1.0f);
+
   AddComment(R"DOC(
 Momentum Optimizer.
 
@@ -109,4 +123,12 @@ REGISTER_OP_VERSION(momentum)
                      "l2decay or none",
                      std::string(""))
             .NewAttr("regularization_coeff", "(float) regularization_coeff",
-                     0.0f));
+                     0.0f)
+            .NewAttr(
+                "multi_precision",
+                "(bool) Whether to use multi-precision during weight updating.",
+                false)
+            .NewAttr("rescale_grad",
+                     "(float) Multiply the gradient with `rescale_grad`"
+                     "before updating. Often choose to be `1.0/batch_size`.",
+                     1.0f));

paddle/fluid/operators/optimizers/momentum_op.h

@@ -19,6 +19,7 @@ limitations under the License. */
 #include "paddle/fluid/framework/op_registry.h"
 #include "paddle/fluid/operators/math/algorithm.h"
 #include "paddle/fluid/operators/math/selected_rows_functor.h"
+#include "paddle/fluid/platform/float16.h"
 #include "paddle/fluid/platform/for_range.h"
 
 namespace paddle {
@@ -29,6 +30,44 @@ using framework::SelectedRows;
 struct NoNesterov;
 struct UseNesterov;
 
+namespace details {
+
+template <typename T>
+class MPTypeTrait {
+ public:
+  using Type = T;
+};
+template <>
+class MPTypeTrait<platform::float16> {
+ public:
+  using Type = float;
+};
+
+template <typename T>
+struct CPUDenseUpdater {
+  template <typename G>
+  void operator()(const Tensor& param, const Tensor& velocity, const T& mu,
+                  const T& lr, const bool use_nesterov, G&& grad,
+                  Tensor* param_out, Tensor* velocity_out) const {
+    auto param_out_vec = framework::EigenVector<T>::Flatten(*param_out);
+    auto velocity_out_vec = framework::EigenVector<T>::Flatten(*velocity_out);
+
+    auto param_vec = framework::EigenVector<T>::Flatten(param);
+    auto velocity_vec = framework::EigenVector<T>::Flatten(velocity);
+    velocity_out_vec = velocity_vec * mu + grad;
+    if (use_nesterov) {
+      param_out_vec = param_vec - (grad + velocity_out_vec * mu) * lr;
+    } else {
+      param_out_vec = param_vec - lr * velocity_out_vec;
+    }
+  }
+};
+
+}  // namespace details
+
+template <typename T>
+using MultiPrecisionType = typename details::MPTypeTrait<T>::Type;
+
 enum class RegularizationType {
   kNONE = 0,
   kL1DECAY = 1,  // do not need support right now
@@ -118,350 +157,427 @@ class MomentumOp : public framework::OperatorWithKernel {
 
 template <typename T>
 class CPUDenseMomentumFunctor {
- private:
-  const Tensor* param_;
-  const Tensor* grad_;
-  const Tensor* velocity_;
-  const Tensor* learning_rate_;
-  const T mu_;
-  const T use_nesterov_;
-  RegularizationType regularization_flag_;
-  const T regularization_coeff_;
-  Tensor* param_out_;
-  Tensor* velocity_out_;
-
  public:
-  CPUDenseMomentumFunctor(const Tensor* param, const Tensor* grad,
-                          const Tensor* velocity, const Tensor* learning_rate,
-                          const T mu, const bool use_nesterov,
-                          RegularizationType regularization_flag,
-                          const T regularization_coeff, Tensor* param_out,
-                          Tensor* velocity_out)
-      : param_(param),
-        grad_(grad),
-        velocity_(velocity),
-        learning_rate_(learning_rate),
-        mu_(mu),
-        use_nesterov_(use_nesterov),
-        regularization_flag_(regularization_flag),
-        regularization_coeff_(regularization_coeff),
-        param_out_(param_out),
-        velocity_out_(velocity_out) {}
-
-  inline void operator()() {
-    auto param_out = framework::EigenVector<T>::Flatten(*param_out_);
-    auto velocity_out = framework::EigenVector<T>::Flatten(*velocity_out_);
-
-    auto param = framework::EigenVector<T>::Flatten(*param_);
-    auto velocity = framework::EigenVector<T>::Flatten(*velocity_);
-    auto grad = framework::EigenVector<T>::Flatten(*grad_);
-    auto* lr = learning_rate_->data<T>();
-
-    if (regularization_flag_ == RegularizationType::kL2DECAY) {
-      velocity_out = velocity * mu_ + param * regularization_coeff_ + grad;
-      if (use_nesterov_) {
-        param_out =
-            param -
-            (param * regularization_coeff_ + grad + velocity_out * mu_) * lr[0];
-      } else {
-        param_out = param - lr[0] * velocity_out;
-      }
+  void operator()(const Tensor* param, const Tensor* grad,
+                  const Tensor* velocity, const Tensor* learning_rate,
+                  const T mu, const bool use_nesterov,
+                  const RegularizationType regularization_flag,
+                  const T regularization_coeff, Tensor* param_out,
+                  Tensor* velocity_out) {
+    auto grad_vec = framework::EigenVector<T>::Flatten(*grad);
+    auto* lr = learning_rate->data<MultiPrecisionType<T>>();
+
+    details::CPUDenseUpdater<T> updater;
+    if (regularization_flag == RegularizationType::kL2DECAY) {
+      auto param_vec = framework::EigenVector<T>::Flatten(*param);
+      updater(*param, *velocity, mu, static_cast<T>(lr[0]), use_nesterov,
+              param_vec * regularization_coeff + grad_vec, param_out,
+              velocity_out);
     } else {
-      velocity_out = velocity * mu_ + grad;
-      if (use_nesterov_) {
-        param_out = param - (grad + velocity_out * mu_) * lr[0];
-      } else {
-        param_out = param - lr[0] * velocity_out;
-      }
+      updater(*param, *velocity, mu, static_cast<T>(lr[0]), use_nesterov,
+              grad_vec, param_out, velocity_out);
     }
   }
 };
 
-template <typename T, typename UpdateMethod>
+template <typename T, typename MT, typename UpdateMethod>
 class DenseMomentumFunctor;
 
 // NOTE(dzh) for performance.
 // avoid if/else in inside kernel, implement GPU UseNesterov/NoNesterov as two
 // functor.
-template <typename T>
-class DenseMomentumFunctor<T, UseNesterov> {
+template <typename T, typename MT>
+class DenseMomentumFunctor<T, MT, UseNesterov> {
  private:
   const T* param_;
   const T* grad_;
-  const T* velocity_;
-  const T* lr_;
-  const T mu_;
+  const MT* velocity_;
+  const MultiPrecisionType<MT>* lr_;
+  const MT* master_param_;
+  const MT mu_;
+  const MT rescale_grad_;
   const int64_t num_;
   T* param_out_;
-  T* velocity_out_;
-  RegularizationType regularization_flag_;
-  const T regularization_coeff_;
+  MT* velocity_out_;
+  MT* master_param_out_;
+  const RegularizationType regularization_flag_;
+  const MT regularization_coeff_;
 
  public:
-  DenseMomentumFunctor(const T* param, const T* grad, const T* velocity,
-                       const T* learning_rate, const T mu, const int64_t num,
-                       RegularizationType regularization_flag,
-                       const T regularization_coeff, T* param_out,
-                       T* velocity_out)
+  DenseMomentumFunctor(const T* param, const T* grad, const MT* velocity,
+                       const MultiPrecisionType<MT>* learning_rate,
+                       const MT* master_param, const MT mu,
+                       const MT rescale_grad, const int64_t num,
+                       const RegularizationType regularization_flag,
+                       const MT regularization_coeff, T* param_out,
+                       MT* velocity_out, MT* master_param_out)
       : param_(param),
         grad_(grad),
         velocity_(velocity),
         lr_(learning_rate),
+        master_param_(master_param),
         mu_(mu),
+        rescale_grad_(rescale_grad),
         num_(num),
         param_out_(param_out),
         velocity_out_(velocity_out),
+        master_param_out_(master_param_out),
         regularization_flag_(regularization_flag),
         regularization_coeff_(regularization_coeff) {}
-
   inline HOSTDEVICE void operator()(size_t i) const {
     // put memory access in register
-    const T param = param_[i];
-    T grad = grad_[i];
-    const T lr = lr_[0];
-    const T velocity = velocity_[i];
+    const MT param =
+        master_param_ ? master_param_[i] : static_cast<MT>(param_[i]);
+    MT grad = static_cast<MT>(grad_[i]) * rescale_grad_;
+    const MT lr = static_cast<MT>(lr_[0]);
+    const MT velocity = velocity_[i];
 
     grad = regularization_flag_ == RegularizationType::kL2DECAY
                ? grad + regularization_coeff_ * param
                : grad;
 
-    T velocity_out = velocity * mu_ + grad;
-    T param_out = param - (grad + velocity_out * mu_) * lr;
+    MT velocity_out = velocity * mu_ + grad;
+    MT param_out = param - (grad + velocity_out * mu_) * lr;
     // write reigster to memory
     velocity_out_[i] = velocity_out;
-    param_out_[i] = param_out;
+    param_out_[i] = static_cast<T>(param_out);
+    if (master_param_out_) {
+      master_param_out_[i] = param_out;
+    }
   }
 };
 
-template <typename T>
-class DenseMomentumFunctor<T, NoNesterov> {
+template <typename T, typename MT>
+class DenseMomentumFunctor<T, MT, NoNesterov> {
  private:
   const T* param_;
   const T* grad_;
-  const T* velocity_;
-  const T* lr_;
-  const T mu_;
+  const MT* velocity_;
+  const MultiPrecisionType<MT>* lr_;
+  const MT* master_param_;
+  const MT mu_;
+  const MT rescale_grad_;
   const int64_t num_;
   T* param_out_;
-  T* velocity_out_;
-  RegularizationType regularization_flag_;
-  const T regularization_coeff_;
+  MT* velocity_out_;
+  MT* master_param_out_;
+  const RegularizationType regularization_flag_;
+  const MT regularization_coeff_;
 
  public:
-  DenseMomentumFunctor(const T* param, const T* grad, const T* velocity,
-                       const T* learning_rate, const T mu, const int64_t num,
-                       RegularizationType regularization_flag,
-                       const T regularization_coeff, T* param_out,
-                       T* velocity_out)
+  DenseMomentumFunctor(const T* param, const T* grad, const MT* velocity,
+                       const MultiPrecisionType<MT>* learning_rate,
+                       const MT* master_param, const MT mu,
+                       const MT rescale_grad, const int64_t num,
+                       const RegularizationType regularization_flag,
+                       const MT regularization_coeff, T* param_out,
+                       MT* velocity_out, MT* master_param_out)
       : param_(param),
         grad_(grad),
         velocity_(velocity),
         lr_(learning_rate),
+        master_param_(master_param),
         mu_(mu),
+        rescale_grad_(rescale_grad),
         num_(num),
         param_out_(param_out),
         velocity_out_(velocity_out),
+        master_param_out_(master_param_out),
         regularization_flag_(regularization_flag),
         regularization_coeff_(regularization_coeff) {}
-
   inline HOSTDEVICE void operator()(size_t i) const {
     // put memory access in register
-    const T param = param_[i];
-    T grad = grad_[i];
-    const T lr = lr_[0];
-    const T velocity = velocity_[i];
+    const MT param =
+        master_param_ ? master_param_[i] : static_cast<MT>(param_[i]);
+    MT grad = static_cast<MT>(grad_[i]) * rescale_grad_;
+    const MT lr = static_cast<MT>(lr_[0]);
+    const MT velocity = velocity_[i];
 
     grad = regularization_flag_ == RegularizationType::kL2DECAY
                ? grad + regularization_coeff_ * param
                : grad;
 
-    T velocity_out = velocity * mu_ + grad;
-    T param_out = param - lr * velocity_out;
+    MT velocity_out = velocity * mu_ + grad;
+    MT param_out = param - lr * velocity_out;
     // write reigster to memory
     velocity_out_[i] = velocity_out;
-    param_out_[i] = param_out;
+    param_out_[i] = static_cast<T>(param_out);
+    if (master_param_out_) {
+      master_param_out_[i] = param_out;
+    }
   }
 };
 
-template <typename T, typename UpdateMethod>
+template <typename T, typename MT, typename UpdateMethod>
 class SparseMomentumFunctor;
 
-template <typename T>
-class SparseMomentumFunctor<T, UseNesterov> {
+template <typename T, typename MT>
+class SparseMomentumFunctor<T, MT, UseNesterov> {
  private:
   const T* param_;
   const T* grad_;
-  const T* velocity_;
-  const T* lr_;
-  const T mu_;
+  const MT* velocity_;
+  const MultiPrecisionType<MT>* lr_;
+  const MT* master_param_;
+  const MT mu_;
+  const MT rescale_grad_;
   const int64_t* rows_;
   const int64_t row_numel_;
   const int64_t row_height_;
   T* param_out_;
-  T* velocity_out_;
-  RegularizationType regularization_flag_;
-  const T regularization_coeff_;
+  MT* velocity_out_;
+  MT* master_param_out_;
+  const RegularizationType regularization_flag_;
+  const MT regularization_coeff_;
 
  public:
-  SparseMomentumFunctor(const T* param, const T* grad, const T* velocity,
-                        const T* lr, const T mu, const int64_t* rows,
+  SparseMomentumFunctor(const T* param, const T* grad, const MT* velocity,
+                        const MultiPrecisionType<MT>* lr,
+                        const MT* master_param, const MT mu,
+                        const MT rescale_grad, const int64_t* rows,
                         int64_t row_numel, int64_t row_height,
-                        RegularizationType regularization_flag,
-                        const T regularization_coeff, T* param_out,
-                        T* velocity_out)
+                        const RegularizationType regularization_flag,
+                        const MT regularization_coeff, T* param_out,
+                        MT* velocity_out, MT* master_param_out)
       : param_(param),
         grad_(grad),
         velocity_(velocity),
         lr_(lr),
+        master_param_(master_param),
         mu_(mu),
+        rescale_grad_(rescale_grad),
         rows_(rows),
         row_numel_(row_numel),
         row_height_(row_height),
         param_out_(param_out),
         velocity_out_(velocity_out),
+        master_param_out_(master_param_out),
         regularization_flag_(regularization_flag),
         regularization_coeff_(regularization_coeff) {}
 
   inline HOSTDEVICE void operator()(size_t i) {
     auto row_idx =
         math::BinarySearch<int64_t>(rows_, row_height_, i / row_numel_);
-    T grad = row_idx >= 0 ? grad_[row_idx * row_numel_ + i % row_numel_]
-                          : static_cast<T>(0);
+    MT grad =
+        row_idx >= 0
+            ? static_cast<MT>(grad_[row_idx * row_numel_ + i % row_numel_]) *
+                  rescale_grad_
+            : static_cast<MT>(0);
     // put memory access in register
-    const T param = param_[i];
-    const T lr = lr_[0];
-    const T velocity = velocity_[i];
+    const MT param =
+        master_param_ ? master_param_[i] : static_cast<MT>(param_[i]);
+    const MT lr = static_cast<MT>(lr_[0]);
+    const MT velocity = velocity_[i];
 
     grad = regularization_flag_ == RegularizationType::kL2DECAY
                ? grad + regularization_coeff_ * param
                : grad;
 
-    T velocity_out = velocity * mu_ + grad;
-    T param_out = param - (grad + velocity_out * mu_) * lr;
+    MT velocity_out = velocity * mu_ + grad;
+    MT param_out = param - (grad + velocity_out * mu_) * lr;
     // write reigster to memory
     velocity_out_[i] = velocity_out;
-    param_out_[i] = param_out;
+    param_out_[i] = static_cast<T>(param_out);
+    if (master_param_out_) {
+      master_param_out_[i] = param_out;
+    }
   }
 };
 
-template <typename T>
-class SparseMomentumFunctor<T, NoNesterov> {
+template <typename T, typename MT>
+class SparseMomentumFunctor<T, MT, NoNesterov> {
  private:
   const T* param_;
   const T* grad_;
-  const T* velocity_;
-  const T* lr_;
-  const T mu_;
+  const MT* velocity_;
+  const MultiPrecisionType<MT>* lr_;
+  const MT* master_param_;
+  const MT mu_;
+  const MT rescale_grad_;
   const int64_t* rows_;
   const int64_t row_numel_;
   const int64_t row_height_;
   T* param_out_;
-  T* velocity_out_;
-  RegularizationType regularization_flag_;
-  const T regularization_coeff_;
+  MT* velocity_out_;
+  MT* master_param_out_;
+  const RegularizationType regularization_flag_;
+  const MT regularization_coeff_;
 
  public:
-  SparseMomentumFunctor(const T* param, const T* grad, const T* velocity,
-                        const T* lr, const T mu, const int64_t* rows,
+  SparseMomentumFunctor(const T* param, const T* grad, const MT* velocity,
+                        const MultiPrecisionType<MT>* lr,
+                        const MT* master_param, const MT mu,
+                        const MT rescale_grad, const int64_t* rows,
                         int64_t row_numel, int64_t row_height,
-                        RegularizationType regularization_flag,
-                        const T regularization_coeff, T* param_out,
-                        T* velocity_out)
+                        const RegularizationType regularization_flag,
+                        const MT regularization_coeff, T* param_out,
+                        MT* velocity_out, MT* master_param_out)
       : param_(param),
         grad_(grad),
         velocity_(velocity),
         lr_(lr),
+        master_param_(master_param),
         mu_(mu),
+        rescale_grad_(rescale_grad),
         rows_(rows),
         row_numel_(row_numel),
         row_height_(row_height),
         param_out_(param_out),
         velocity_out_(velocity_out),
+        master_param_out_(master_param_out),
         regularization_flag_(regularization_flag),
         regularization_coeff_(regularization_coeff) {}
 
   inline HOSTDEVICE void operator()(size_t i) {
     auto row_idx =
         math::BinarySearch<int64_t>(rows_, row_height_, i / row_numel_);
-    T grad = row_idx >= 0 ? grad_[row_idx * row_numel_ + i % row_numel_]
-                          : static_cast<T>(0);
+    MT grad =
+        row_idx >= 0
+            ? static_cast<MT>(grad_[row_idx * row_numel_ + i % row_numel_]) *
+                  rescale_grad_
+            : static_cast<MT>(0);
     // put memory access in register
-    const T param = param_[i];
-    const T lr = lr_[0];
-    const T velocity = velocity_[i];
+    const MT param =
+        master_param_ ? master_param_[i] : static_cast<MT>(param_[i]);
+    const MT lr = static_cast<MT>(lr_[0]);
+    const MT velocity = velocity_[i];
 
     grad = regularization_flag_ == RegularizationType::kL2DECAY
                ? grad + regularization_coeff_ * param
                : grad;
 
-    T velocity_out = velocity * mu_ + grad;
-    T param_out = param - velocity_out * lr;
+    MT velocity_out = velocity * mu_ + grad;
+    MT param_out = param - velocity_out * lr;
     // write reigster to memory
     velocity_out_[i] = velocity_out;
-    param_out_[i] = param_out;
+    param_out_[i] = static_cast<T>(param_out);
+    if (master_param_out_) {
+      master_param_out_[i] = param_out;
+    }
   }
 };
 
 template <typename DeviceContext, typename T>
 class MomentumOpKernel : public framework::OpKernel<T> {
+  using MPDType = MultiPrecisionType<T>;
+
  public:
   void Compute(const framework::ExecutionContext& ctx) const override {
-    std::string regularization_method =
-        ctx.Attr<std::string>("regularization_method");
-    if (regularization_method != "" || !regularization_method.empty()) {
-      PADDLE_ENFORCE_EQ("l2_decay", regularization_method,
-                        platform::errors::InvalidArgument(
-                            "if regularization_method is not null, "
-                            "it should be l2_decay, but received %s",
-                            regularization_method));
+    const bool multi_precision = ctx.Attr<bool>("multi_precision");
+    if (multi_precision) {
+      LOG_FIRST_N(INFO, 1) << R"CODE(
+      InnerCompute<MPDType>(ctx, multi_precision);
+      )CODE";
+      InnerCompute<MPDType>(ctx, multi_precision);
+    } else {
+      LOG_FIRST_N(INFO, 1) << R"CODE(
+      InnerCompute<T>(ctx, multi_precision);
+      )CODE";
+      InnerCompute<T>(ctx, multi_precision);
     }
+  }
 
-    T regularization_coeff =
-        static_cast<T>(ctx.Attr<float>("regularization_coeff"));
+ private:
+  template <typename MT>
+  void InnerCompute(const framework::ExecutionContext& ctx,
+                    const bool multi_precision) const {
+    std::string regularization_method =
+        ctx.Attr<std::string>("regularization_method");
+    MT regularization_coeff =
+        static_cast<MT>(ctx.Attr<float>("regularization_coeff"));
     RegularizationType regularization_flag{
         RegularizationType::kNONE};  // disable regularization
     if (regularization_method == "l2_decay") {
       regularization_flag = RegularizationType::kL2DECAY;
     }
 
-    T mu = static_cast<T>(ctx.Attr<float>("mu"));
+    MT mu = static_cast<MT>(ctx.Attr<float>("mu"));
+    MT rescale_grad = static_cast<MT>(ctx.Attr<float>("rescale_grad"));
     bool use_nesterov = ctx.Attr<bool>("use_nesterov");
 
     auto learning_rate = ctx.Input<framework::Tensor>("LearningRate");
     auto param = ctx.Input<framework::Tensor>("Param");
     auto param_out = ctx.Output<framework::Tensor>("ParamOut");
-    auto* velocity = ctx.Input<framework::Tensor>("Velocity");
+    auto velocity = ctx.Input<framework::Tensor>("Velocity");
     auto velocity_out = ctx.Output<framework::Tensor>("VelocityOut");
 
+    const framework::Tensor* master_param = nullptr;
+    framework::Tensor* master_param_out = nullptr;
+    if (multi_precision) {
+      LOG_FIRST_N(INFO, 1) << R"CODE(
+      bool has_master =
+          ctx.HasInput("MasterParam") && ctx.HasOutput("MasterParamOut");
+      PADDLE_ENFORCE_EQ(has_master, true,
+                        platform::errors::InvalidArgument(
+                            "The Input(MasterParam) and Output(MasterParamOut) "
+                            "should not be null when "
+                            "the attr `multi_precision` is true"));
+      master_param = ctx.Input<framework::Tensor>("MasterParam");
+      master_param_out = ctx.Output<framework::Tensor>("MasterParamOut");
+      )CODE";
+      bool has_master =
+          ctx.HasInput("MasterParam") && ctx.HasOutput("MasterParamOut");
+      PADDLE_ENFORCE_EQ(has_master, true,
+                        platform::errors::InvalidArgument(
+                            "The Input(MasterParam) and Output(MasterParamOut) "
+                            "should not be null when "
+                            "the attr `multi_precision` is true"));
+      master_param = ctx.Input<framework::Tensor>("MasterParam");
+      master_param_out = ctx.Output<framework::Tensor>("MasterParamOut");
+    }
+
     param_out->mutable_data<T>(ctx.GetPlace());
-    velocity_out->mutable_data<T>(ctx.GetPlace());
+    velocity_out->mutable_data<MT>(ctx.GetPlace());
+    const MT* master_in_data =
+        multi_precision ? master_param->data<MT>() : nullptr;
+    MT* master_out_data =
+        multi_precision ? master_param_out->mutable_data<MT>(ctx.GetPlace())
+                        : nullptr;
 
     auto* grad_var = ctx.InputVar("Grad");
     if (grad_var->IsType<framework::LoDTensor>()) {
       auto grad = ctx.Input<framework::Tensor>("Grad");
       if (platform::is_cpu_place(ctx.GetPlace())) {
-        CPUDenseMomentumFunctor<T> functor(
-            param, grad, velocity, learning_rate, mu, use_nesterov,
-            regularization_flag, regularization_coeff, param_out, velocity_out);
-        functor();
+        CPUDenseMomentumFunctor<MT> functor;
+        functor(param, grad, velocity, learning_rate, mu, use_nesterov,
+                regularization_flag, regularization_coeff, param_out,
+                velocity_out);
       } else if (platform::is_gpu_place(ctx.GetPlace())) {
         platform::ForRange<DeviceContext> for_range(
             static_cast<const DeviceContext&>(ctx.device_context()),
             param->numel());
         if (use_nesterov) {
-          DenseMomentumFunctor<T, UseNesterov> functor(
-              param->data<T>(), grad->data<T>(), velocity->data<T>(),
-              learning_rate->data<T>(), mu, param->numel(), regularization_flag,
-              regularization_coeff, param_out->mutable_data<T>(ctx.GetPlace()),
-              velocity_out->mutable_data<T>(ctx.GetPlace()));
+          LOG_FIRST_N(INFO, 1) << R"CODE(
+          DenseMomentumFunctor<T, MT, UseNesterov> functor(
+              param->data<T>(), grad->data<T>(), velocity->data<MT>(),
+              learning_rate->data<MPDType>(), master_in_data, mu, rescale_grad,
+              param->numel(), regularization_flag, regularization_coeff,
+              param_out->mutable_data<T>(ctx.GetPlace()),
+              velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
+          )CODE";
+          DenseMomentumFunctor<T, MT, UseNesterov> functor(
+              param->data<T>(), grad->data<T>(), velocity->data<MT>(),
+              learning_rate->data<MPDType>(), master_in_data, mu, rescale_grad,
+              param->numel(), regularization_flag, regularization_coeff,
+              param_out->mutable_data<T>(ctx.GetPlace()),
+              velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
           for_range(functor);
 
         } else {
-          DenseMomentumFunctor<T, NoNesterov> functor(
-              param->data<T>(), grad->data<T>(), velocity->data<T>(),
-              learning_rate->data<T>(), mu, param->numel(), regularization_flag,
-              regularization_coeff, param_out->mutable_data<T>(ctx.GetPlace()),
-              velocity_out->mutable_data<T>(ctx.GetPlace()));
+          LOG_FIRST_N(INFO, 1) << R"CODE(
+          DenseMomentumFunctor<T, MT, NoNesterov> functor(
+              param->data<T>(), grad->data<T>(), velocity->data<MT>(),
+              learning_rate->data<MPDType>(), master_in_data, mu, rescale_grad,
+              param->numel(), regularization_flag, regularization_coeff,
+              param_out->mutable_data<T>(ctx.GetPlace()),
+              velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
+          )CODE";
+          DenseMomentumFunctor<T, MT, NoNesterov> functor(
+              param->data<T>(), grad->data<T>(), velocity->data<MT>(),
+              learning_rate->data<MPDType>(), master_in_data, mu, rescale_grad,
+              param->numel(), regularization_flag, regularization_coeff,
+              param_out->mutable_data<T>(ctx.GetPlace()),
+              velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
           for_range(functor);
         }
       }
@@ -489,23 +605,25 @@ class MomentumOpKernel : public framework::OpKernel<T> {
           static_cast<const DeviceContext&>(ctx.device_context()),
           param->numel());
       if (use_nesterov) {
-        SparseMomentumFunctor<T, UseNesterov> functor(
+        SparseMomentumFunctor<T, MT, UseNesterov> functor(
             param->data<T>(), merged_grad->value().data<T>(),
-            velocity->data<T>(), learning_rate->data<T>(), mu, rows, row_numel,
+            velocity->data<MT>(), learning_rate->data<MPDType>(),
+            master_in_data, mu, rescale_grad, rows, row_numel,
             static_cast<int64_t>(merged_grad->rows().size()),
             regularization_flag, regularization_coeff,
             param_out->mutable_data<T>(ctx.GetPlace()),
-            velocity_out->mutable_data<T>(ctx.GetPlace()));
+            velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
         for_range(functor);
 
       } else {
-        SparseMomentumFunctor<T, NoNesterov> functor(
+        SparseMomentumFunctor<T, MT, NoNesterov> functor(
             param->data<T>(), merged_grad->value().data<T>(),
-            velocity->data<T>(), learning_rate->data<T>(), mu, rows, row_numel,
+            velocity->data<MT>(), learning_rate->data<MPDType>(),
+            master_in_data, mu, rescale_grad, rows, row_numel,
             static_cast<int64_t>(merged_grad->rows().size()),
             regularization_flag, regularization_coeff,
             param_out->mutable_data<T>(ctx.GetPlace()),
-            velocity_out->mutable_data<T>(ctx.GetPlace()));
+            velocity_out->mutable_data<MT>(ctx.GetPlace()), master_out_data);
         for_range(functor);
       }
     } else {

paddle/fluid/pybind/op_function_generator.cc

@@ -54,6 +54,7 @@ std::map<std::string, std::set<std::string>> op_ins_map = {
     {"moving_average_abs_max_scale", {"X", "InAccum", "InState"}},
     {"multiclass_nms3", {"BBoxes", "Scores", "RoisNum"}},
     {"box_coder", {"PriorBox", "PriorBoxVar", "TargetBox"}},
+    {"momentum", {"Param", "Grad", "Velocity", "LearningRate"}},
 };
 
 // NOTE(zhiqiu): Like op_ins_map.
@@ -82,6 +83,7 @@ std::map<std::string, std::set<std::string>> op_outs_map = {
     {"moving_average_abs_max_scale", {"OutScale", "OutAccum", "OutState"}},
     {"multiclass_nms3", {"Out", "NmsRoisNum"}},
     {"generate_proposals_v2", {"RpnRois", "RpnRoiProbs", "RpnRoisNum"}},
+    {"momentum", {"ParamOut", "VelocityOut"}},
 };
 
 // NOTE(zhiqiu): Commonly, the outputs in auto-generated OP function are

python/paddle/fluid/contrib/mixed_precision/fp16_utils.py

@@ -16,6 +16,12 @@ from __future__ import print_function
 
 from ... import core
 from ... import layers
+from ... import global_scope
+from ...log_helper import get_logger
+import logging
+import numpy as np
+_logger = get_logger(
+    __name__, logging.INFO, fmt='%(asctime)s-%(levelname)s: %(message)s')
 
 
 def _rename_arg(op, old_name, new_name):
@@ -191,6 +197,127 @@ def _is_in_black_varnames(op, amp_lists):
     return False
 
 
+def cast_model_to_fp16(main_program):
+    """
+    Traverse all ops in the whole model and set their inputs and outputs
+    to the fp16 data type. This function will do some special process for
+    the batch normalization, which keeps the computational process of
+    batchnorms in FP32.
+    Args:
+        main_program (Program): The main program for training.
+    """
+    valid_types = [
+        core.VarDesc.VarType.LOD_TENSOR, core.VarDesc.VarType.SELECTED_ROWS,
+        core.VarDesc.VarType.LOD_TENSOR_ARRAY
+    ]
+    global_block = main_program.global_block()
+
+    for block in main_program.blocks:
+        ops = block.ops
+        for op in ops:
+            if op.type == 'create_py_reader' or op.type == 'read':
+                continue
+            for in_name in op.input_names:
+                if op.type in {
+                        'batch_norm', 'fused_bn_add_activation', 'layer_norm'
+                } and in_name not in {'X', 'Z'}:
+                    continue
+                for in_var_name in op.input(in_name):
+                    in_var = None
+                    try:
+                        in_var = block.var(in_var_name)
+                    except ValueError as e:
+                        _logger.debug(
+                            "-- {}, try to get it in the global block. --".
+                            format(e))
+                        in_var = global_block.var(in_var_name)
+                        if in_var is not None:
+                            _logger.debug(
+                                "-- var {} is got in the global block. --".
+                                format(in_var_name))
+
+                    if in_var is None or in_var.type not in valid_types:
+                        continue
+
+                    if in_var.dtype == core.VarDesc.VarType.FP32:
+                        in_var.desc.set_dtype(core.VarDesc.VarType.FP16)
+
+                    _logger.debug(
+                        "-- op type: {}, in var name: {}, in var dtype: {} --".
+                        format(op.type, in_var_name, in_var.dtype))
+
+            for out_name in op.output_names:
+                if op.type in {
+                        'batch_norm', 'fused_bn_add_activation', 'layer_norm'
+                } and out_name != 'Y':
+                    continue
+                for out_var_name in op.output(out_name):
+                    out_var = None
+                    try:
+                        out_var = block.var(out_var_name)
+                    except ValueError as e:
+                        _logger.debug(
+                            "-- {}, try to get it in the global block. --".
+                            format(e))
+                        out_var = global_block.var(out_var_name)
+                        if out_var is not None:
+                            _logger.debug(
+                                "-- var {} is got in the global block. --".
+                                format(out_var_name))
+
+                    if out_var is None or out_var.type not in valid_types:
+                        continue
+
+                    if out_var.dtype == core.VarDesc.VarType.FP32:
+                        out_var.desc.set_dtype(core.VarDesc.VarType.FP16)
+
+                    _logger.debug(
+                        "-- op type: {}, out var name: {}, out var dtype: {} --".
+                        format(op.type, out_var_name, out_var.dtype))
+            if op.has_attr('in_dtype') and op.attr(
+                    'in_dtype') == core.VarDesc.VarType.FP32:
+                op._set_attr('in_dtype', core.VarDesc.VarType.FP16)
+            if op.has_attr('out_dtype') and op.attr(
+                    'out_dtype') == core.VarDesc.VarType.FP32:
+                op._set_attr('out_dtype', core.VarDesc.VarType.FP16)
+            if op.has_attr('dtype') and op.attr(
+                    'dtype') == core.VarDesc.VarType.FP32:
+                op._set_attr('dtype', core.VarDesc.VarType.FP16)
+
+
+def cast_parameters_to_fp16(place, main_program, scope=None):
+    """
+    Traverse all parameters in the whole model and set them to the fp16 data type.
+    Whereas, this function will keep parameters of batchnorms in FP32.
+    Args:
+        place(fluid.CPUPlace|fluid.CUDAPlace): place is used to restore the weight tensors.
+        main_program (Program): The main program for training.
+        scope(fluid.Scope, optional): scope is used to get the weight tensor values.
+        Default is None.
+    """
+    all_ops = []
+    for block in main_program.blocks:
+        all_ops.extend(block.ops)
+    bn_params = set()
+    for op in all_ops:
+        if op.type not in {
+                'batch_norm', 'fused_bn_add_activation', 'layer_norm'
+        }:
+            continue
+        for in_name in op.input_names:
+            if in_name not in {'X', 'Z'}:
+                for in_var_name in op.input(in_name):
+                    bn_params.add(in_var_name)
+    global_block = main_program.global_block()
+    all_parameters = global_block.all_parameters()
+    var_scope = scope if scope is not None else global_scope()
+    for param in all_parameters:
+        if param.name not in bn_params:
+            param_t = var_scope.find_var(param.name).get_tensor()
+            data = np.array(param_t)
+            param_t.set(np.float16(data), place)
+
+
 def rewrite_program(main_prog, amp_lists):
     """
     Traverse all ops in current block and insert cast op according to 

python/paddle/fluid/contrib/optimizer.py

@@ -14,11 +14,13 @@
 from paddle.fluid.optimizer import Optimizer
 from paddle.fluid.regularizer import L1DecayRegularizer
 from paddle.fluid.regularizer import L2DecayRegularizer
-from paddle.fluid.regularizer import append_regularization_ops
-from paddle.fluid import framework
 from paddle.fluid import core
+from paddle.fluid import framework
 from paddle.fluid.framework import program_guard
-from paddle.fluid.clip import append_gradient_clip_ops
+from paddle.fluid import unique_name
+from paddle.fluid import layers
+from paddle.fluid.layer_helper import LayerHelper
+import warnings
 
 __all__ = ['Momentum']
 
@@ -61,6 +63,9 @@ class Momentum(Optimizer):
             some derived class of ``GradientClipBase`` . There are three cliping strategies 
             ( :ref:`api_fluid_clip_GradientClipByGlobalNorm` , :ref:`api_fluid_clip_GradientClipByNorm` , 
             :ref:`api_fluid_clip_GradientClipByValue` ). Default None, meaning there is no gradient clipping.
+        multi_precision (bool, optional): Whether to use multi-precision during weight updating. Default is false.
+        rescale_grad (float, optional): Multiply the gradient with `rescale_grad` before updating. \
+            Often choose to be ``1.0/batch_size``.
         name (str, optional): This parameter is used by developers to print debugging information. \
             For details, please refer to :ref:`api_guide_Name`. Default is None.
 
@@ -105,6 +110,8 @@ class Momentum(Optimizer):
                  use_nesterov=False,
                  regularization=None,
                  grad_clip=None,
+                 multi_precision=False,
+                 rescale_grad=1.0,
                  name=None):
         assert learning_rate is not None
         assert momentum is not None
@@ -124,11 +131,68 @@ class Momentum(Optimizer):
         if (isinstance(regularization, L2DecayRegularizer)):
             self._regularization_method = "l2_decay"
             self._regularization_coeff = regularization._regularization_coeff
+        self._multi_precision = multi_precision
+        self._rescale_grad = rescale_grad
+        self._master_weights = {}
+
+    def _create_master_weight(self, param):
+        assert isinstance(self.helper, LayerHelper)
+
+        var_name = param.name + "_fp32_master"
+        var_name = unique_name.generate(var_name)
+        var = layers.create_global_var(
+            name=var_name,
+            shape=param.shape,
+            value=0,
+            dtype='float32',
+            persistable=True)
+        block = self.helper.startup_program.global_block()
+        block.append_op(
+            type="cast",
+            inputs={"X": [param]},
+            outputs={"Out": [var]},
+            attrs={
+                "in_dtype": param.dtype,
+                "out_dtype": core.VarDesc.VarType.FP32
+            })
+        self._master_weights[param.name] = var
+        return var
+
+    def _get_accumulator(self, name, param):
+        """Utility function to fetch an accumulator for a parameter
+
+        Args:
+            name: name of the accumulator
+            param: parameter variable for which accumulator is to be fetched
+
+        Returns:
+            accumulator variable for the parameter
+        """
+        if self._name is not None:
+            name = self._name + "_" + name
+        find_master = self._multi_precision and param.dtype == core.VarDesc.VarType.FP16
+        target_param = self._master_weights[
+            param.name] if find_master else param
+        target_name = target_param.name
+        if (name not in self._accumulators or
+                target_name not in self._accumulators[name]):
+            raise Exception("Accumulator {} does not exist for parameter {}".
+                            format(name, target_name))
+        return self._accumulators[name][target_name]
 
     def _create_accumulators(self, block, parameters):
         assert isinstance(block, framework.Block)
 
         for p in parameters:
+            if self._multi_precision and p.dtype == core.VarDesc.VarType.FP16:
+                master_p = self._create_master_weight(p)
+                self._add_accumulator(self._velocity_acc_str, master_p)
+                continue
+            if p.dtype == core.VarDesc.VarType.FP16 and not self._multi_precision:
+                warnings.warn(
+                    "Accumulating with FP16 in optimizer can lead to poor accuracy or slow convergence."
+                    "Consider using multi_precision=True option of the Momentum optimizer."
+                )
             self._add_accumulator(self._velocity_acc_str, p)
 
     def _append_optimize_op(self, block, param_and_grad):
@@ -136,6 +200,10 @@ class Momentum(Optimizer):
 
         velocity_acc = self._get_accumulator(self._velocity_acc_str,
                                              param_and_grad[0])
+        find_master = self._multi_precision and param_and_grad[
+            0].dtype == core.VarDesc.VarType.FP16
+        master_weight = (self._master_weights[param_and_grad[0].name]
+                         if find_master else None)
         lr = self._create_param_lr(param_and_grad)
 
         if framework.in_dygraph_mode():
@@ -151,7 +219,9 @@ class Momentum(Optimizer):
             "mu": self._momentum,
             "use_nesterov": self._use_nesterov,
             "regularization_method": self._regularization_method,
-            "regularization_coeff": self._regularization_coeff
+            "regularization_coeff": self._regularization_coeff,
+            "multi_precision": find_master,
+            "rescale_grad": self._rescale_grad
         }
         inputs = {
             "Param": [param_and_grad[0]],
@@ -159,11 +229,15 @@ class Momentum(Optimizer):
             "Velocity": [velocity_acc],
             "LearningRate": [lr]
         }
-
         outputs = {
             "ParamOut": [param_and_grad[0]],
             "VelocityOut": [velocity_acc]
         }
+
+        if find_master:
+            inputs["MasterParam"] = master_weight
+            outputs["MasterParamOut"] = master_weight
+
         # create the momentum optimize op
         momentum_op = block.append_op(
             type=self.type,

python/paddle/fluid/contrib/tests/CMakeLists.txt

 file(GLOB TEST_OPS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "test_*.py")
 string(REPLACE ".py" "" TEST_OPS "${TEST_OPS}")
 
+list(REMOVE_ITEM TEST_OPS test_multi_precision_fp16_train)
+
 foreach(src ${TEST_OPS})
         py_test(${src} SRCS ${src}.py)
 endforeach()
+
+py_test_modules(test_multi_precision_fp16_train MODULES test_multi_precision_fp16_train ENVS FLAGS_cudnn_deterministic=true FLAGS_cudnn_batchnorm_spatial_persistent=true FLAGS_conv_workspace_size_limit=1000)
+
 set_tests_properties(test_image_classification_fp16 PROPERTIES TIMEOUT 120)
 set_tests_properties(test_weight_decay_extend PROPERTIES TIMEOUT 120)
+set_tests_properties(test_multi_precision_fp16_train PROPERTIES TIMEOUT 120)

python/paddle/fluid/contrib/tests/test_multi_precision_fp16_train.py

+#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# 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.
+
+from __future__ import print_function
+
+import paddle
+import paddle.fluid as fluid
+import contextlib
+import unittest
+import numpy as np
+from paddle.fluid.contrib.mixed_precision.fp16_utils import cast_model_to_fp16
+from paddle.fluid.contrib.mixed_precision.fp16_utils import cast_parameters_to_fp16
+
+paddle.enable_static()
+
+
+def resnet_cifar10(input, depth=32):
+    def conv_bn_layer(input,
+                      ch_out,
+                      filter_size,
+                      stride,
+                      padding,
+                      act='relu',
+                      bias_attr=False):
+        tmp = fluid.layers.conv2d(
+            input=input,
+            filter_size=filter_size,
+            num_filters=ch_out,
+            stride=stride,
+            padding=padding,
+            act=None,
+            bias_attr=bias_attr)
+        return fluid.layers.batch_norm(input=tmp, act=act)
+
+    def shortcut(input, ch_in, ch_out, stride):
+        if ch_in != ch_out:
+            return conv_bn_layer(input, ch_out, 1, stride, 0, None)
+        else:
+            return input
+
+    def basicblock(input, ch_in, ch_out, stride):
+        tmp = conv_bn_layer(input, ch_out, 3, stride, 1)
+        tmp = conv_bn_layer(tmp, ch_out, 3, 1, 1, act=None, bias_attr=True)
+        short = shortcut(input, ch_in, ch_out, stride)
+        return fluid.layers.elementwise_add(x=tmp, y=short, act='relu')
+
+    def layer_warp(block_func, input, ch_in, ch_out, count, stride):
+        tmp = block_func(input, ch_in, ch_out, stride)
+        for i in range(1, count):
+            tmp = block_func(tmp, ch_out, ch_out, 1)
+        return tmp
+
+    assert (depth - 2) % 6 == 0
+    n = (depth - 2) // 6
+    conv1 = conv_bn_layer(
+        input=input, ch_out=16, filter_size=3, stride=1, padding=1)
+    res1 = layer_warp(basicblock, conv1, 16, 16, n, 1)
+    res2 = layer_warp(basicblock, res1, 16, 32, n, 2)
+    res3 = layer_warp(basicblock, res2, 32, 64, n, 2)
+    pool = fluid.layers.pool2d(
+        input=res3, pool_size=8, pool_type='avg', pool_stride=1)
+    return pool
+
+
+def compile(program, loss_name=None):
+    build_strategy = paddle.static.BuildStrategy()
+    exec_strategy = paddle.static.ExecutionStrategy()
+
+    exec_strategy.num_threads = 1
+    exec_strategy.num_iteration_per_drop_scope = 10000
+
+    build_strategy.fuse_bn_act_ops = True
+    build_strategy.fuse_elewise_add_act_ops = True
+    build_strategy.fuse_bn_add_act_ops = True
+
+    compiled_program = paddle.static.CompiledProgram(
+        program).with_data_parallel(
+            loss_name=loss_name,
+            build_strategy=build_strategy,
+            exec_strategy=exec_strategy)
+
+    return compiled_program
+
+
+def train(use_pure_fp16=True, use_nesterov=False):
+    classdim = 10
+    data_shape = [3, 32, 32]
+    BATCH_SIZE = 128
+    PASS_NUM = 1
+
+    train_program = fluid.Program()
+    startup_prog = fluid.Program()
+    train_program.random_seed = 123
+    startup_prog.random_seed = 456
+    with fluid.program_guard(train_program, startup_prog):
+        images = fluid.layers.data(
+            name='pixel', shape=data_shape, dtype='float32')
+        label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+        net = resnet_cifar10(images, 32)
+
+        logits = fluid.layers.fc(input=net, size=classdim, act="softmax")
+        if use_pure_fp16:
+            cast_model_to_fp16(fluid.default_main_program())
+            logits_fp32 = fluid.layers.cast(x=logits, dtype="float32")
+        else:
+            logits_fp32 = logits
+        cost = fluid.layers.softmax_with_cross_entropy(
+            logits_fp32, label, return_softmax=False)
+        sum_cost = fluid.layers.reduce_sum(cost)
+
+        # Test program
+        test_program = train_program.clone(for_test=True)
+
+        optimizer = fluid.contrib.optimizer.Momentum(
+            learning_rate=0.001,
+            momentum=0.9,
+            use_nesterov=use_nesterov,
+            regularization=fluid.regularizer.L2Decay(1e-4),
+            multi_precision=use_pure_fp16,
+            rescale_grad=1.0 / BATCH_SIZE)
+
+        optimizer.minimize(sum_cost)
+
+    # no shuffle for unit test
+    train_reader = paddle.batch(
+        paddle.dataset.cifar.train10(), batch_size=BATCH_SIZE)
+
+    test_reader = paddle.batch(
+        paddle.dataset.cifar.test10(), batch_size=BATCH_SIZE)
+
+    place = fluid.CUDAPlace(0)
+    exe = fluid.Executor(place)
+    feeder = fluid.DataFeeder(place=place, feed_list=[images, label])
+
+    def train_loop(main_program):
+        exe.run(startup_prog)
+        if use_pure_fp16:
+            cast_parameters_to_fp16(place, train_program, fluid.global_scope())
+        compiled_program = compile(train_program, sum_cost.name)
+        loss = 0.0
+        for pass_id in range(PASS_NUM):
+            train_loss_list = []
+            for batch_id, data in enumerate(train_reader()):
+                loss, = exe.run(compiled_program,
+                                feed=feeder.feed(data),
+                                fetch_list=[sum_cost])
+                print('PassID {0:1}, Train Batch ID {1:04}, train loss {2:2.4}'.
+                      format(pass_id, batch_id + 1, float(loss)))
+                train_loss_list.append(float(loss))
+
+                if batch_id >= 4:  # For speeding up CI
+                    test_loss_list = []
+                    for tid, test_data in enumerate(test_reader()):
+                        loss_t, = exe.run(program=test_program,
+                                          feed=feeder.feed(test_data),
+                                          fetch_list=[sum_cost])
+                        test_loss_list.append(float(loss_t))
+                        print(
+                            'PassID {0:1}, Test Batch ID {1:04}, test loss {2:2.4}'.
+                            format(pass_id, tid + 1, float(loss_t)))
+                        if tid >= 4:
+                            break  # For speeding up CI
+                    return train_loss_list, test_loss_list
+
+    return train_loop(train_program)
+
+
+class TestImageMultiPrecision(unittest.TestCase):
+    def test_resnet_pure_fp16(self):
+        if not fluid.core.is_compiled_with_cuda():
+            return
+
+        def do_test(use_nesterov=False):
+            suffix = "with Nesterov" if use_nesterov else "without Nesterov"
+            with self.scope_prog_guard():
+                print("-----------------FP16 Train {}-----------------".format(
+                    suffix))
+                train_loss_fp16, test_loss_fp16 = train(
+                    use_pure_fp16=True, use_nesterov=use_nesterov)
+            with self.scope_prog_guard():
+                print("-----------------FP32 Train {}-----------------".format(
+                    suffix))
+                train_loss_fp32, test_loss_fp32 = train(
+                    use_pure_fp16=False, use_nesterov=use_nesterov)
+
+            self.assertTrue(
+                np.allclose(
+                    np.array(train_loss_fp16),
+                    np.array(train_loss_fp32),
+                    rtol=1e-02,
+                    atol=1e-05,
+                    equal_nan=True),
+                msg='Failed to train in pure FP16.')
+            self.assertTrue(
+                np.allclose(
+                    np.array(test_loss_fp16),
+                    np.array(test_loss_fp32),
+                    rtol=1e-02,
+                    atol=1e-05,
+                    equal_nan=True),
+                msg='Failed to test in pure FP16.')
+
+        do_test(use_nesterov=False)
+        do_test(use_nesterov=True)
+
+    @contextlib.contextmanager
+    def scope_prog_guard(self):
+        prog = fluid.Program()
+        startup_prog = fluid.Program()
+        scope = fluid.core.Scope()
+        with fluid.scope_guard(scope):
+            with fluid.program_guard(prog, startup_prog):
+                yield
+
+
+class TestAmpWithNonIterableDataLoader(unittest.TestCase):
+    def decorate_with_data_loader(self):
+        main_prog = paddle.static.Program()
+        start_prog = paddle.static.Program()
+        with paddle.static.program_guard(main_prog, start_prog):
+            with paddle.fluid.unique_name.guard():
+                image = fluid.layers.data(
+                    name='image', shape=[3, 224, 224], dtype='float32')
+                label = fluid.layers.data(
+                    name='label', shape=[1], dtype='int64')
+                py_reader = fluid.io.DataLoader.from_generator(
+                    feed_list=[image, label],
+                    capacity=4,
+                    iterable=False,
+                    use_double_buffer=False)
+                zero_var = fluid.layers.fill_constant(
+                    shape=[1], dtype='int64', value=0)
+                one_var = fluid.layers.fill_constant(
+                    shape=[1], dtype='int64', value=1)
+                with fluid.layers.control_flow.Switch() as switch:
+                    with switch.case(label != zero_var):
+                        fluid.layers.assign(input=zero_var, output=label)
+                    with switch.default():
+                        fluid.layers.assign(input=one_var, output=label)
+
+                net = resnet_cifar10(image)
+                logits = fluid.layers.fc(input=net, size=10, act="softmax")
+
+        block = main_prog.global_block()
+        for op in block.ops:
+            if op.type == "mul":
+                op._set_attr('in_dtype', fluid.core.VarDesc.VarType.FP32)
+                op._set_attr('out_dtype', fluid.core.VarDesc.VarType.FP32)
+                op._set_attr('dtype', fluid.core.VarDesc.VarType.FP32)
+
+        cast_model_to_fp16(main_prog)
+
+    def test_non_iterable_dataloader(self):
+        self.decorate_with_data_loader()
+
+
+if __name__ == '__main__':
+    unittest.main()

python/paddle/fluid/incubate/fleet/parameter_server/ir/pserver_pass.py

@@ -246,7 +246,8 @@ def _append_pserver_ops(optimize_block, opt_op, endpoint, grad_to_block_id,
     for key in opt_op.input_names:
         new_shape = None
         if key in [
-                "Param", "Grad", "LearningRate", "Beta1Tensor", "Beta2Tensor"
+                "Param", "Grad", "LearningRate", "MasterParam", "Beta1Tensor",
+                "Beta2Tensor"
         ]:
             continue
         var = origin_program.global_block().vars[opt_op.input(key)[0]]

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

@@ -59,7 +59,7 @@ class TestMomentumOp1(OpTest):
         param = np.random.random((123, 321)).astype(self.dtype)
         grad = np.random.random((123, 321)).astype(self.dtype)
         velocity = np.zeros((123, 321)).astype(self.dtype)
-        learning_rate = np.array([0.001]).astype(self.dtype)
+        learning_rate = np.array([0.001]).astype(np.float32)
         mu = 0.0001
         use_nesterov = False
 
@@ -217,7 +217,7 @@ class TestSparseMomentumOp(unittest.TestCase):
                                         0.0).astype("float32")
         velocity_out.set(velocity_out_np_array, place)
 
-        # create and initialize LeraningRate Variable
+        # create and initialize LearningRate Variable
         lr = scope.var('LearningRate').get_tensor()
         lr_array = np.full((1), 2.0).astype("float32")
         lr.set(lr_array, place)
@@ -278,6 +278,115 @@ class TestSparseMomentumOp2(TestSparseMomentumOp):
         self.use_nesterov = True
 
 
+class TestSparseMomentumOpWithMultiPrecision(unittest.TestCase):
+    def setUp(self):
+        self.init_args()
+        self.regularization_method = ""
+        self.regularization_coeff = 1.0
+
+    def check_with_place(self, place):
+        scope = core.Scope()
+        # create and initialize Grad Variable
+        height = 10
+        rows = [0, 4, 7]
+        row_numel = 12
+        mu = 1.0
+        use_nesterov = self.use_nesterov
+        regularization_method = self.regularization_method
+        regularization_coeff = self.regularization_coeff
+
+        # create and initialize Param Variable
+        param_array = np.full((height, row_numel), 5.0).astype("float32")
+        param_out_array = np.full((height, row_numel), 0.0).astype("float32")
+
+        param = scope.var('Param').get_tensor()
+        param.set(param_array.astype("float16"), place)
+        param_out = scope.var("ParamOut").get_tensor()
+        param_out.set(param_out_array.astype("float16"), place)
+
+        master_param = scope.var('MasterParam').get_tensor()
+        master_param.set(param_array, place)
+        master_param_out = scope.var("MasterParamOut").get_tensor()
+        master_param_out.set(param_out_array, place)
+
+        grad_selected_rows = scope.var('Grad').get_selected_rows()
+        grad_selected_rows.set_height(height)
+        grad_selected_rows.set_rows(rows)
+        grad_np_array = np.ones((len(rows), row_numel)).astype("float32")
+        grad_np_array[0, 0] = 2.0
+        grad_np_array[2, 8] = 4.0
+        grad_tensor = grad_selected_rows.get_tensor()
+        grad_tensor.set(grad_np_array.astype("float16"), place)
+
+        velocity = scope.var('Velocity').get_tensor()
+        velocity_np_array = np.ones((height, row_numel)).astype("float32")
+        velocity.set(velocity_np_array, place)
+        velocity_out = scope.var('VelocityOut').get_tensor()
+        velocity_out_np_array = np.full((height, row_numel),
+                                        0.0).astype("float32")
+        velocity_out.set(velocity_out_np_array, place)
+
+        # create and initialize LearningRate Variable
+        lr = scope.var('LearningRate').get_tensor()
+        lr_array = np.full((1), 2.0).astype("float32")
+        lr.set(lr_array, place)
+
+        # create and run operator
+        op = Operator(
+            "momentum",
+            Param='Param',
+            Grad='Grad',
+            Velocity='Velocity',
+            MasterParam='MasterParam',
+            ParamOut='ParamOut',
+            VelocityOut='VelocityOut',
+            MasterParamOut='MasterParamOut',
+            LearningRate='LearningRate',
+            mu=mu,
+            use_nesterov=use_nesterov,
+            regularization_method=regularization_method,
+            regularization_coeff=regularization_coeff,
+            multi_precision=True,
+            rescale_grad=1.0)
+        op.run(scope, place)
+
+        # get and compare result
+        param_out_np_array = np.array(param_out)
+        velocity_out_np_array = np.array(velocity_out)
+
+        _grad_np_array = np.full((height, row_numel), 0.0).astype("float32")
+        for i in range(len(rows)):
+            _grad_np_array[rows[i]] = grad_np_array[i]
+
+        _param = param_array
+
+        _param_out, _velocity_out = calculate_momentum_by_numpy(
+            param=_param,
+            grad=_grad_np_array,
+            mu=mu,
+            velocity=velocity_np_array,
+            use_nesterov=use_nesterov,
+            learning_rate=lr_array,
+            regularization_method=regularization_method,
+            regularization_coeff=regularization_coeff)
+
+        self.assertTrue((_velocity_out == velocity_out_np_array).all())
+        self.assertTrue((_param_out == param_out_np_array).all())
+
+    def init_args(self):
+        self.use_nesterov = False
+
+    def test_sparse_momentum(self):
+        if core.is_compiled_with_cuda():
+            self.check_with_place(fluid.CUDAPlace(0))
+
+
+class TestSparseMomentumOpWithMultiPrecision2(
+        TestSparseMomentumOpWithMultiPrecision):
+    def init_args(self):
+        self.use_nesterov = True
+
+
 class TestMomentumV2(unittest.TestCase):
     def test_momentum_dygraph(self):
         paddle.disable_static()
@@ -334,7 +443,7 @@ class TestMomentumOpWithDecay(OpTest):
         param = np.random.random((123, 321)).astype(self.dtype)
         grad = np.random.random((123, 321)).astype(self.dtype)
         velocity = np.zeros((123, 321)).astype(self.dtype)
-        learning_rate = np.array([0.001]).astype(self.dtype)
+        learning_rate = np.array([0.001]).astype(np.float32)
         mu = 0.0001
         use_nesterov = self.use_nesterov
         regularization_method = self.regularization_method