From 70825506d1561d53c1efdfc5a50ef8cb8a4c4f9f Mon Sep 17 00:00:00 2001
From: dongzhihong <dzhwinter@gmail.com>
Date: Wed, 9 Aug 2017 00:28:04 +0800
Subject: [PATCH] "remove context random seeding "

---
 paddle/platform/device_context.cc |  7 ++-----
 paddle/platform/device_context.h  | 14 ++------------
 2 files changed, 4 insertions(+), 17 deletions(-)

diff --git a/paddle/platform/device_context.cc b/paddle/platform/device_context.cc
index f80c36b5b23..a928e097787 100644
--- a/paddle/platform/device_context.cc
+++ b/paddle/platform/device_context.cc
@@ -21,12 +21,10 @@ Eigen::DefaultDevice* DeviceContext::get_eigen_device<Eigen::DefaultDevice>()
 }
 
 CPUDeviceContext::CPUDeviceContext() {
-  random_seed_ = std::chrono::system_clock::now().time_since_epoch().count();
   eigen_device_.reset(new Eigen::DefaultDevice());
 }
 
 CPUDeviceContext::CPUDeviceContext(CPUPlace place) {
-  random_seed_ = std::chrono::system_clock::now().time_since_epoch().count();
   eigen_device_.reset(new Eigen::DefaultDevice());
 }
 
@@ -44,7 +42,6 @@ Eigen::GpuDevice* DeviceContext::get_eigen_device<Eigen::GpuDevice>() const {
 }
 
 CUDADeviceContext::CUDADeviceContext(GPUPlace place) : place_(place) {
-  random_seed_ = std::chrono::system_clock::now().time_since_epoch().count();
   SetDeviceId(place_.device);
   // TODO(qijun) Pass a created cuda stream to Eigen::CudaStreamDevice directly
   // here will cause segment fault. We must implement a class derived from
@@ -111,8 +108,8 @@ curandGenerator_t CUDADeviceContext::curand_generator() {
     SetDeviceId(place_.device);
     PADDLE_ENFORCE(dynload::curandCreateGenerator(&curand_generator_,
                                                   CURAND_RNG_PSEUDO_DEFAULT));
-    PADDLE_ENFORCE(dynload::curandSetPseudoRandomGeneratorSeed(
-        curand_generator_, random_seed_));
+    PADDLE_ENFORCE(
+        dynload::curandSetPseudoRandomGeneratorSeed(curand_generator_, seed_));
   }
   return curand_generator_;
 }
diff --git a/paddle/platform/device_context.h b/paddle/platform/device_context.h
index 450213c34af..08b5b2cff90 100644
--- a/paddle/platform/device_context.h
+++ b/paddle/platform/device_context.h
@@ -21,7 +21,6 @@ limitations under the License. */
 #include "paddle/platform/gpu_info.h"
 #define EIGEN_USE_GPU
 #endif
-#include <chrono>
 #include <memory>
 #include "paddle/platform/place.h"
 #include "unsupported/Eigen/CXX11/Tensor"
@@ -40,7 +39,6 @@ class DeviceContext {
 
 class CPUDeviceContext : public DeviceContext {
  public:
-  typedef std::mt19937 random_generator_type;
   CPUDeviceContext();
   explicit CPUDeviceContext(CPUPlace);
   virtual ~CPUDeviceContext() {}
@@ -49,16 +47,7 @@ class CPUDeviceContext : public DeviceContext {
 
   Place GetPlace() const override;
 
-  random_generator_type& RandGenerator() {
-    if (!rand_generator_) {
-      rand_generator_.reset(new random_generator_type(random_seed_));
-    }
-    return *rand_generator_.get();
-  }
-
  private:
-  unsigned random_seed_;
-  std::unique_ptr<random_generator_type> rand_generator_;
   std::unique_ptr<Eigen::DefaultDevice> eigen_device_;
 };
 
@@ -97,7 +86,8 @@ class CUDADeviceContext : public DeviceContext {
   std::unique_ptr<Eigen::CudaStreamDevice> eigen_stream_;
 
  private:
-  unsigned random_seed_;
+  uint64_t seed_;
+
   // clang-format off
   cudnnHandle_t     cudnn_handle_     = nullptr;
   cublasHandle_t    cublas_handle_    = nullptr;
-- 
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