# 28 Numerics library [numerics]

## 28.5 Random number generation [rand]

### 28.5.9 Random number distribution class templates [rand.dist]

#### 28.5.9.5.5 Class template fisher_f_distribution[rand.dist.norm.f]

A fisher_f_distribution random number distribution produces random numbers x  ≥ 0 distributed according to the probability density function
namespace std { template<class RealType = double> class fisher_f_distribution { public: // types using result_type = RealType; using param_type = unspecified; // constructor and reset functions fisher_f_distribution() : fisher_f_distribution(1.0) {} explicit fisher_f_distribution(RealType m, RealType n = 1.0); explicit fisher_f_distribution(const param_type& parm); void reset(); // equality operators friend bool operator==(const fisher_f_distribution& x, const fisher_f_distribution& y); // generating functions template<class URBG> result_type operator()(URBG& g); template<class URBG> result_type operator()(URBG& g, const param_type& parm); // property functions RealType m() const; RealType n() const; param_type param() const; void param(const param_type& parm); result_type min() const; result_type max() const; // inserters and extractors template<class charT, class traits> friend basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& os, const fisher_f_distribution& x); template<class charT, class traits> friend basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>& is, fisher_f_distribution& x); }; }
```explicit fisher_f_distribution(RealType m, RealType n = 1); ```
Preconditions: and .
Remarks: m and n correspond to the respective parameters of the distribution.
```RealType m() const; ```
Returns: The value of the m parameter with which the object was constructed.
```RealType n() const; ```
Returns: The value of the n parameter with which the object was constructed.