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std::linear_congruential_engine - cppreference.com

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template< class UIntType, UIntType a, UIntType c, UIntType m > class linear_congruential_engine;

 (since C++11)

linear_congruential_engine is a random number engine based on Linear congruential generator (LCG).

Template parameters

UIntType - The result type generated by the generator. The effect is undefined if this is not one of unsigned short, unsigned int, unsigned long, or unsigned long long.
a - the multiplier term
c - the increment term
m - the modulus term

When m is not zero, if a >= m or c >= m is true, the program is ill-formed.

Generator properties

The size of the states of linear_congruential_engine is 1, each of them consists of a single integer.

The actual modulus m0 is defined as follows:

  • If m is not zero, m0 is m.
  • If m is zero, m0 is the value of std::numeric_limits<result_type>::max() plus 1 (which means m0 need not be representable as result_type).

The transition algorithm of linear_congruential_engine is TA(xi) = (a·xi+c) mod m0.

The generation algorithm of linear_congruential_engine is GA(xi) = (a·xi+c) mod m0.

The pseudo-random number generated with the current state is also the successor state.

Predefined specializations

The following specializations define the random number engine with two commonly used parameter sets:

Type Definition
minstd_rand0 (C++11) std::linear_congruential_engine<std::uint_fast32_t,
                                16807, 0, 2147483647>

Discovered in 1969 by Lewis, Goodman and Miller, adopted as "Minimal standard" in 1988 by Park and Miller[edit]

minstd_rand (C++11)

std::linear_congruential_engine<std::uint_fast32_t,
                                48271, 0, 2147483647>
Newer "Minimum standard", recommended by Park, Miller, and Stockmeyer in 1993[edit]

Nested types

Type Definition
result_type UIntType

Data members

constexpr UIntType multiplier

[static]

 a
(public static member constant)

constexpr UIntType increment

[static]

 c
(public static member constant)

constexpr UIntType modulus

[static]

 m
(public static member constant)

constexpr UIntType default_seed

[static]

 1u
(public static member constant)

Member functions

Construction and Seeding
constructs the engine
(public member function) [edit]
sets the current state of the engine
(public member function) [edit]
Generation
advances the engine's state and returns the generated value
(public member function) [edit]
advances the engine's state by a specified amount
(public member function) [edit]
Characteristics

[static]

 gets the smallest possible value in the output range
(public static member function) [edit]

[static]

 gets the largest possible value in the output range
(public static member function) [edit]

Non-member functions

Example