播种default_random_engine？ [英] seeding default_random_engine?

问题描述

我使用的Visual Studio 2010不支持< chrono> ，所以我必须种子 default_random_engine 。因此，我决定以 rand 种子如下

  srand（（unsigned int）time（NULL））; 
 std :: default_random_engine engine（rand（））; 
 std :: normal_distribution< double> randn（0.0，0.3）; 
  

而不是以下

  unsigned seed = std :: chrono :: system_clock :: now（）。time_since_epoch（）。count（）; 
 std :: default_random_engine engine（seed）; 
 std :: normal_distribution< double> randn（0.0，0.3）; 
  

我得到我想要获得的两种方法。我的问题是有任何注意事项，我应该注意使用rand（）？ （注意：我不能使用< chrono>

解决方案

我建议从 std :: random_device 获取种子， ：

  std :: default_random_engine engine（std :: random_device {}（））; 
   
 
 
这将为您提供比 std :: time  。
 
I'm using visual studio 2010 which doesn't support <chrono>, so I have to seed default_random_engine. Thus, I've decided to seed it with rand as following
srand((unsigned int)time(NULL));
std::default_random_engine engine(rand());
std::normal_distribution<double> randn(0.0, 0.3);
instead of the following
unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
std::default_random_engine engine(seed);
std::normal_distribution<double> randn(0.0, 0.3);
I'm getting what I'm expecting to acquire for both methods. My question is are there any considerations should I pay attention to by using rand()? (Note: I have no choice to use <chrono>
解决方案
I recommend grabbing a seed from std::random_device:
std::default_random_engine engine(std::random_device{}());
which should provide you with significantly more entropy than std::time.

                        
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