RandomNumberDistribution

A RandomNumberDistribution is a function object returning random numbers according to a probability density function p(x) or a discrete probability distribution P(x
i).

Requirements

D is a class meeting the RandomNumberDistribution requirements. It shall also satisfy the CopyConstructible and CopyAssignable requirements.
T is the associated result_type.
P is the associated param_type. It shall satisfy the CopyConstructible, CopyAssignable, and EqualityComparable requirements. It also has constructors that take the same arguments of the same types as the constructors of D and has member functions identical to the parameter-returning getters of D
d is an object of D and x,y are potentially const objects of D.
p is a possibly constant value of P.
g,g1,g2 are lvalues meeting the UniformRandomNumberGenerator concept.
os is an lvalue of std::basic_ostream.
is is an lvalue of std::basic_istream.

Expression	Type	Notes	Complexity
`D::result_type`	`T`	An arithmetic type	compile-time
`D::param_type`	`P`		compile-time
`D()`			constant
`D(p)`			Same as `p`'s construction
`d.reset()`	`void`	Resets the internal state of the distribution object. After a call to this function, the next call to `operator()` on the distribution object will not be dependent on previous calls to `operator()`.	constant
`x.param()`	`P`		No worse than `D(p)`
`d.param(p)`	`void`		No worse than `D(p)`
`d(g)`	`T`	`d(g, d.param())`	Same as `d(g, d.param())`
`d(g,p)`	`T`	When called with the same `g` and `p` parameter it returns a sequence of numbers distributed according to p(x;`p`) or P(x i;`p`)	Amortized constant number of invocations of `g`
`x.min()`	`T`	The greatest lower bound returned by `operator()`	constant
`x.max()`	`T`	The least upper bound returned by `operator()`	constant
`x == y`	`bool`		constant
`x != y`	`bool`	`!(x == y)`	constant
`os << x`	Reference to the type of `os`	Writes a textual representation of the distribution parameters and internal state to `os` as textual representation. The formatting flags and fill character of `os` are unchanged.
`is >> d`	Reference to the type of `is`	Restores the distribution parameters and internal state with data read from `is`. The formatting flags of `is` are unchanged. The data must have been written using a stream with the same locale, `CharT` and `Traits` template parameters, otherwise the behavior is undefined. If bad input is encountered, `is.setstate(std::ios::failbit)` is called, which may throw `std::ios_base::failure`. `d` is unchanged in that case.

Notes

The parameters of a distribution object may be changed either permanently, by using d.param(p) or just for the duration of a single operator() call, by using d(g,p).

Links:

http://en.cppreference.com/w/cpp/concept/RandomNumberDistribution

doc_CPP

2016-10-11 09:59:54

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