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

[rand.dist.norm.lognormal]

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]

29.5.9.5.2 Class template lognormal_distribution [rand.dist.norm.lognormal]

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A lognormal_distribution random number distribution produces random numbers x>0 distributed according to the probability density function in Formula 29.14.

p(x|m,s)=1sx√2πâ‹exp(−(lnx−m)22s2)(29.14)

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namespace std {templateclass lognormal_distribution {public:// typesusing result_type = RealType; using param_type = unspecified; // constructor and reset functions lognormal_distribution() : lognormal_distribution(0.0) {}explicit lognormal_distribution(RealType m, RealType s = 1.0); explicit lognormal_distribution(const param_type& parm); void reset(); // equality operatorsfriend bool operator==(const lognormal_distribution& x, const lognormal_distribution& y); // generating functionstemplate result_type operator()(URBG& g); template result_type operator()(URBG& g, const param_type& parm); // property functions RealType m() const; RealType s() 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 lognormal_distribution& x); template<class charT, class traits>friend basic_istream<charT, traits>&operator>>(basic_istream<charT, traits>& is, lognormal_distribution& x); };}

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explicit lognormal_distribution(RealType m, RealType s = 1.0);

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Preconditions: 0<s.

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Remarks: m and s correspond to the respective parameters of the distribution.

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RealType m() const;

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

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RealType s() const;

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