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std::mersenne_twister_engine<UIntType,w,n,m,r,a,u,d,s,b,t,c,l,f>::mersenne_twister_engine

From cppreference.com
 
 
 
Pseudo-random number generation
Uniform random bit generators
Engines and engine adaptors
Non-deterministic generator
Distributions
Uniform distributions
Bernoulli distributions
Poisson distributions
Normal distributions
Sampling distributions
Seed Sequences
(C++11)
C library
 
std::mersenne_twister_engine
Member functions
mersenne_twister_engine::mersenne_twister_engine
(C++11)
Generation
Characteristics
Non-member functions
(C++11)(C++11)(until C++20)
(C++11)(C++11)
 
mersenne_twister_engine() : mersenne_twister_engine(default_seed) {}
(1) (since C++11)
explicit mersenne_twister_engine( result_type value );
(2) (since C++11)
template< class Sseq >
explicit mersenne_twister_engine( Sseq& s );
(3) (since C++11)
mersenne_twister_engine( const mersenne_twister_engine& );
(4) (since C++11)
(implicitly declared)

Constructs the pseudo-random number engine.

1) Default constructor. Seeds the engine with default_seed.
2) Constructs the engine and initializes the state (n values X
i
of type result_type) as follows: value mod 2w
is used to initialize X
0
and the rest are initialized iteratively, for i=1-n,...,-1, each X
i
is initialized to [f·(X
i-1
xor(X
i-1
rshift(w-2)))+i mod n] mod 2w
3) Constructs the engine and initializes the state by calling s.generate(a, a+n*k) where a is an array of length n*k and k is ceil(w/32) and then, iteratively for i=-n,...,-1, setting each element of the engine state X
i
to k-1
j=0
a
k(i+n)+j}·232j
) mod 2w
, and finally if the most significant w-r bits of X
0
are zero, and if all other X
i
are zero, replacing X
0
with 2w-1
.

Note: initialization requirements are based on the 2002 version of Mersenne Twister, mt19937ar.c

The overload (3) only participates in overload resolution if Sseq qualifies as a SeedSequence. In particular, it is excluded from the set of candidate functions if Sseq is convertible to result_type.

Contents

[edit] Parameters

value - seed value to use in the initialization of the internal state
s - seed sequence to use in the initialization of the internal state

[edit] Complexity

linear in n (the state size)

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
P0935R0 C++11 default constructor was explicit made implicit

[edit] See also

(C++11)
sets the current state of the engine
(public member function) [edit]