From 62efc896e1fb1e895414d77d4193891fdee4ca99 Mon Sep 17 00:00:00 2001
From: wanghaoshuang <wanghaoshuang@baidu.com>
Date: Thu, 7 Dec 2017 17:02:49 +0800
Subject: [PATCH] Refine code 1. Add copyright info 2. Overload structure for
 customized random seed

---
 paddle/operators/math/sampler.cc | 31 +++++++++++++++++++++++++++----
 paddle/operators/math/sampler.h  | 16 ++++++++++++++--
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/paddle/operators/math/sampler.cc b/paddle/operators/math/sampler.cc
index 52628c3b0..4f1cbfe31 100644
--- a/paddle/operators/math/sampler.cc
+++ b/paddle/operators/math/sampler.cc
@@ -1,3 +1,17 @@
+/* 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 "sampler.h"
 
 namespace paddle {
@@ -7,8 +21,13 @@ Sampler::~Sampler() {}
 
 UniformSampler::UniformSampler(int64 range)
     : Sampler(range), inv_range_(1.0 / range) {
-  std::random_device r;
-  random_engine_ = std::make_shared<std::mt19937>(r());
+  random_engine_ = std::make_shared<std::mt19937>(seed_);
+  dist_ = std::make_shared<std::uniform_int_distribution<>>(0, range);
+}
+
+UniformSampler::UniformSampler(int64 range, unsigned int seed)
+    : Sampler(range, seed), inv_range_(1.0 / range) {
+  random_engine_ = std::make_shared<std::mt19937>(seed_);
   dist_ = std::make_shared<std::uniform_int_distribution<>>(0, range);
 }
 
@@ -18,11 +37,15 @@ float UniformSampler::Probability(int64 value) const { return inv_range_; }
 
 LogUniformSampler::LogUniformSampler(int64 range)
     : Sampler(range), log_range_(log(range + 1)) {
-  std::random_device r;
-  random_engine_ = std::make_shared<std::mt19937>(r());
+  random_engine_ = std::make_shared<std::mt19937>(seed_);
   dist_ = std::make_shared<std::uniform_real_distribution<>>(0, 1);
 }
 
+LogUniformSampler::LogUniformSampler(int64 range, unsigned int seed)
+    : Sampler(range, seed), log_range_(log(range + 1)) {
+  random_engine_ = std::make_shared<std::mt19937>(seed_);
+  dist_ = std::make_shared<std::uniform_real_distribution<>>(0, 1);
+}
 int64 LogUniformSampler::Sample() const {
   // Got Log Uniform distribution from uniform distribution by
   // inverse_transform_sampling method
diff --git a/paddle/operators/math/sampler.h b/paddle/operators/math/sampler.h
index bcd7bead3..8f82089e7 100644
--- a/paddle/operators/math/sampler.h
+++ b/paddle/operators/math/sampler.h
@@ -20,14 +20,21 @@ namespace paddle {
 namespace operators {
 namespace math {
 
-// TODO: Support for GPU
+// TODO(wanghaoshuang): Support for GPU
 
 /**
 * Sample integers from [0, range).
 */
 class Sampler {
  public:
-  explicit Sampler(int64 range) : range_(range) { /* check range > 0*/
+  explicit Sampler(int64 range) : range_(range) {
+    PADDLE_ENFORCE_GT(range, 0);
+    std::random_device r;
+    seed_ = r();
+  }
+  explicit Sampler(int64 range, unsigned int seed)
+      : range_(range), seed_(seed) {
+    PADDLE_ENFORCE_GT(range, 0);
   }
   virtual ~Sampler();
   // Sample a single value
@@ -39,6 +46,7 @@ class Sampler {
 
  protected:
   const int64 range_;
+  unsigned int seed_;
 };
 
 /**
@@ -50,6 +58,8 @@ class UniformSampler : public Sampler {
  public:
   explicit UniformSampler(int64 range);
 
+  explicit UniformSampler(int64 range, unsigned int seed);
+
   ~UniformSampler() override {}
 
   int64 Sample() const override;
@@ -71,6 +81,8 @@ class LogUniformSampler : public Sampler {
  public:
   explicit LogUniformSampler(int64 range);
 
+  explicit LogUniformSampler(int64 range, unsigned int seed);
+
   ~LogUniformSampler() override {}
 
   int64 Sample() const override;
-- 
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