使用模板提升随机性

Question

所以我尝试将 Boost.Random mt19937 生成器与模板一起使用。我的 c++ 有点生疏了，但据我所知（文档和 Boost 一样总是含糊不清）它应该采用一个模板参数来指定它的返回类型（浮点数/双精度）。

我现在不知道问题出在哪里......这一切都与<double> 或<float> 一起工作并停止使用模板。

代码如下：

template <class T>
class SpikingMatrixHelper {
public:
    SpikingMatrixHelper(const int seed);
    T generateNumber(const T, const T) const;
private:
    boost::mt19937 gen;
};

template <class T>
SpikingMatrixHelper<T>::SpikingMatrixHelper(const int seed) : gen(seed) {}

template <class T>
T SpikingMatrixHelper<T>::generateNumber(const T min, const T max) const {
    boost::uniform_real<T> dist(min, max);
    boost::variate_generator<boost::mt19937&, boost::uniform_real<T> > g(gen, dist);
    return g();
}

这会引发variate_generator 构造

/path/ [line] error: no matching function for call to ‘boost::variate_generator<boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>&, boost::uniform_real<double> >::variate_generator(const mt19937&, boost::uniform_real<double>&)’
/path/ [line] note: candidates are:
/usr/include/boost/random/variate_generator.hpp:133:3: note: boost::variate_generator<Engine, Distribution>::variate_generator(Engine, Distribution) [with Engine = boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>&, Distribution = boost::uniform_real<double>]
/usr/include/boost/random/variate_generator.hpp:133:3: note:   no known conversion for argument 1 from ‘const mt19937 {aka const boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>}’ to ‘boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>&’
/usr/include/boost/random/variate_generator.hpp:114:7: note: boost::variate_generator<boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>&, boost::uniform_real<double> >::variate_generator(const boost::variate_generator<boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u>&, boost::uniform_real<double> >&)
/usr/include/boost/random/variate_generator.hpp:114:7: note:   candidate expects 1 argument, 2 provided

正如我所说，自从我完成 c++ 以来已经有一段时间了，并且 Boost 文档还有很多要求，所以任何提示都非常感谢......

Answer 1

generateNumber 不能是 const - 它置换了 Mersenne Twister。将其设为mutable，或将函数设为非const。