C++ concepts: UniformRandomNumberGenerator

 

C++

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Technical Specifications

 

C++ concepts

Basic
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable (C++11) MoveConstructible (C++11) Destructible
Layout
TrivialType (C++11) TriviallyCopyable (C++11)	StandardLayoutType (C++11) PODType
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EqualityComparable LessThanComparable Swappable (C++11) ValueSwappable (C++11)	NullablePointer (C++11) Hash (C++11) Allocator
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Iterator OutputIterator InputIterator	ForwardIterator BidirectionalIterator RandomAccessIterator ContiguousIterator (C++17)
Stream I/O
FormattedInputFunction UnformattedInputFunction	FormattedOutputFunction UnformattedOutputFunction
Random Numbers
SeedSequence (C++11) RandomNumberEngine (C++11)	RandomNumberDistribution (C++11) UniformRandomNumberGenerator (C++11) RandomNumberEngineAdaptor (C++11)
Concurrency
BasicLockable (C++11) Lockable (C++11) TimedLockable (C++11)	Mutex (C++11) TimedMutex (C++11) SharedMutex (C++17) SharedTimedMutex (C++14)
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CharTraits pos_type off_type Clock (C++11) BitmaskType	UnaryTypeTrait (C++11) BinaryTypeTrait (C++11) TransformationTrait (C++11) TrivialClock (C++11) LiteralType (C++11)

 

A uniform random number generator is a function object returning unsigned integer values such that each value in the range of possible results has (ideally) equal probability. Any uniform random number generator may be plugged into any random number distribution.

Requirements

The type G satisfies UniformRandomNumberGenerator if

Given

• T, the type named by G::result_type
• g, a value of type G

The following expressions must be valid and have their specified effects

Expression	Return type	Requirements
G::result_type	T	T is an unsigned integer type
G::min()	T	Returns the smallest value that G's operator() may return. The value is strictly less than G::max().
G::max()	T	Returns the largest value that G's operator() may return. The value is strictly greater than G::min()
g()	T	Returns a value in the closed interval [G::min(), G::max()]. Has amortized constant complexity.

Notes

All RandomNumberEngines satisfy this concept.

Standard library

The following standard library facilities expect a UniformRandomNumberGenerator type.

random_shuffleshuffle (until C++17)(C++11)	randomly re-orders elements in a range (function template)
generate_canonical (C++11)	evenly distributes real values of given precision across [0, 1) (function template)
uniform_int_distribution (C++11)	produces integer values evenly distributed across a range (class template)
uniform_real_distribution (C++11)	produces real values evenly distributed across a range (class template)
all other random number distributions

The following standard library facilities satisfy UniformRandomNumberGenerator without additionally satisfying RandomNumberEngine:

random_device

non-deterministic random number generator using hardware entropy source (class)