cppdraft_translate/cppdraft/rand/dist/uni.md

[rand.dist.uni]

29 Numerics library [numerics]

29.5 Random number generation [rand]

29.5.9 Random number distribution class templates [rand.dist]

29.5.9.2 Uniform distributions [rand.dist.uni]

29.5.9.2.1 Class template uniform_int_distribution [rand.dist.uni.int]

1

#

A uniform_int_distribution random number distribution produces random integers i,a ≤ i ≤ b, distributed according to the constant discrete probability function in Formula 29.2.

P(i|a,b)=1/(b−a+1)(29.2)

🔗

namespace std {templateclass uniform_int_distribution {public:// typesusing result_type = IntType; using param_type = unspecified; // constructors and reset functions uniform_int_distribution() : uniform_int_distribution(0) {}explicit uniform_int_distribution(IntType a, IntType b = numeric_limits::max()); explicit uniform_int_distribution(const param_type& parm); void reset(); // equality operatorsfriend bool operator==(const uniform_int_distribution& x, const uniform_int_distribution& y); // generating functionstemplate result_type operator()(URBG& g); template result_type operator()(URBG& g, const param_type& parm); // property functions result_type a() const; result_type b() 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, // hostedconst uniform_int_distribution& x); template<class charT, class traits>friend basic_istream<charT, traits>&operator>>(basic_istream<charT, traits>& is, // hosted uniform_int_distribution& x); };}

🔗

explicit uniform_int_distribution(IntType a, IntType b = numeric_limits<IntType>::max());

2

#

Preconditions: a ≤ b.

3

#

Remarks: a and b correspond to the respective parameters of the distribution.

🔗

result_type a() const;

4

#

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

🔗

result_type b() const;

5

#

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

29.5.9.2.2 Class template uniform_real_distribution [rand.dist.uni.real]

1

#

A uniform_real_distribution random number distribution produces random numbers x,a≤x<b, distributed according to the constant probability density function in Formula 29.3.

p(x|a,b)=1/(b−a)(29.3)

[Note 1:

This implies that p(x | a,b) is undefined when a == b.

— end note]

🔗

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

🔗

explicit uniform_real_distribution(RealType a, RealType b = 1.0);

2

#

Preconditions: a ≤ b andb−a≤numeric_limits::max().

3

#

Remarks: a and b correspond to the respective parameters of the distribution.

🔗

result_type a() const;

4

#

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

🔗

result_type b() const;

5

#

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