cppdraft_translate/cppdraft/rand/dist/norm/normal.md

[rand.dist.norm.normal]

29 Numerics library [numerics]

29.5 Random number generation [rand]

29.5.9 Random number distribution class templates [rand.dist]

29.5.9.5 Normal distributions [rand.dist.norm]

29.5.9.5.1 Class template normal_distribution [rand.dist.norm.normal]

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A normal_distribution random number distribution produces random numbers x distributed according to the probability density function in Formula 29.13.

p(x|μ,σ)=1σ√2πâ‹exp(−(x−μ)22σ2)(29.13)

The distribution parameters μ and σ are also known as this distribution's mean and standard deviation.

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namespace std {templateclass normal_distribution {public:// typesusing result_type = RealType; using param_type = unspecified; // constructors and reset functions normal_distribution() : normal_distribution(0.0) {}explicit normal_distribution(RealType mean, RealType stddev = 1.0); explicit normal_distribution(const param_type& parm); void reset(); // equality operatorsfriend bool operator==(const normal_distribution& x, const normal_distribution& y); // generating functionstemplate result_type operator()(URBG& g); template result_type operator()(URBG& g, const param_type& parm); // property functions RealType mean() const; RealType stddev() const; param_type param() const; void param(const param_type& parm); result_type min() const; result_type max() const; // inserters and extractorstemplate<class charT, class traits>friend basic_ostream<charT, traits>&operator<<(basic_ostream<charT, traits>& os, const normal_distribution& x); template<class charT, class traits>friend basic_istream<charT, traits>&operator>>(basic_istream<charT, traits>& is, normal_distribution& x); };}

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explicit normal_distribution(RealType mean, RealType stddev = 1.0);

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Preconditions: 0<stddev.

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Remarks: mean and stddev correspond to the respective parameters of the distribution.

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RealType mean() const;

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Returns: The value of the mean parameter with which the object was constructed.

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RealType stddev() const;

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Returns: The value of the stddev parameter with which the object was constructed.