std::linear_congruential_engine<UIntType,a,c,m>:: linear_congruential_engine
From cppreference.com
<
cpp
|
numeric
|
random
|
linear congruential engine
|
linear_congruential_engine
(
)
:
linear_congruential_engine
(
default_seed
)
{
}
|
(1) | (since C++11) |
|
explicit
linear_congruential_engine
(
result_type value
)
;
|
(2) | (since C++11) |
|
template
<
class
SeedSeq
>
explicit linear_congruential_engine ( SeedSeq & seq ) ; |
(3) | (since C++11) |
|
linear_congruential_engine
(
const
linear_congruential_engine
&
other
)
;
|
(4) |
(since C++11)
(implicitly declared) |
Constructs the pseudo-random number engine.
1)
The default constructor.
-
If the default-constructed engine is of type
std::minstd_rand0, the 10000th consecutive invocation of it produces the value 1043618065 . -
If the default-constructed engine is of type
std::minstd_rand, the 10000th consecutive invocation of it produces the value 399268537 .
2)
Constructs the engine with a seed value
value
. The engine's initial
state
is determined as follows:
- If c % m == 0 and value % m == 0 are both true , the state is 1 .
- Otherwise, the state is value % m .
3)
Constructs the engine with a seed sequence
seq
. Given
std::
size_t
(
std::
log2
(
m
)
/
32
)
+
1
as
k
, the engine's initial
state
is determined as follows:
- Creates an invented array object a of length k + 3 .
- Calls seq. generate ( a + 0 , a + k + 3 ) .
- Let S be (∑ k-1j=0 a j+3 ·2 32j ) mod m .
- If both c % m == 0 and S == 0 are true , sets the engine's state to 1 . Otherwise, sets the engine’s state to S .
This overload participates in overload resolution only if
SeedSeq
meets the requirements of
SeedSequence
.
4)
The copy constructor. Upon construction,
*
this
==
other
is
true
.
Parameters
| value | - | seed value to use in the initialization of the internal state |
| seq | - | seed sequence to use in the initialization of the internal state |
Complexity
1,2)
Constant.
3)
Same as the complexity of the
seq.generate
call.
4)
Constant.
Exceptions
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2181 | C++11 |
overload
(
3
)
would not throw even if the
seq.generate
call throws
|
propagates the exception |
| P0935R0 | C++11 | the default constructor was explicit | made implicit |
See also
|
sets the current state of the engine
(public member function) |