C++11多随机数引擎适配器

Question

是否可以在C++11中同时使用由STL提供的随机引擎和多个适配器？

例如，使用带有废块发动机适配器的Mersenne引擎(来自基引擎生成的大小P的每个块，适配器只保留R号，丢弃其余的)和洗牌订购引擎适配器 (以不同的顺序传递随机数引擎的输出)。

为不知道的人使用的引擎适配器示例：

//some code here to create a valid seed sequence
mt19937 eng(mySeedSequence);
discard_block_engine<mt19937,11,5> discardWrapper(eng);
shuffle_order_engine<mt19937,50> shuffleWrapper(eng);

for (int i=0; i<100; ++i) {
  //for every 5 calls to "discardWrapper()", the twister engine 
  //advances by 11 states (6 random numbers are thrown away)
  cout << discardWrapper() << endl;
}

for (int i=0; i<100; ++i) {
  //essentially 50 random numbers are generated from the Twister
  //engine and put into a maintained table, one is then picked from
  //the table, not necessarily in the order you would expect if you
  //knew the internal state of the engine
  cout << shuffleWrapper() << endl;
}

Answer 1

是的，你能做到的。您只需要根据另一个适配器类型定义一个适配器类型：

typedef std::discard_block_engine<std::mt19937, 11, 5> discard_engine_t;
typedef std::shuffle_order_engine<discard_engine_t, 50> shuffle_engine_t;

std::mt19937 mt_eng;
discard_engine_t discard_eng(mt_eng);
shuffle_engine_t shuffle_eng(discard_eng);