std::philox_engine<UIntType,w,n,r,consts>:: philox_engine
From cppreference.com
<
cpp
|
numeric
|
random
|
philox engine
|
philox_engine
(
)
:
philox_engine
(
default_seed
)
{
}
|
(1) | (since C++26) |
|
explicit
philox_engine
(
result_type value
)
;
|
(2) | (since C++26) |
|
template
<
class
SeedSeq
>
explicit philox_engine ( SeedSeq & seq ) ; |
(3) | (since C++26) |
|
philox_engine
(
const
philox_engine
&
other
)
;
|
(4) |
(since C++26)
(implicitly declared) |
Constructs the pseudo-random number engine.
1)
The default constructor.
-
If the default-constructed engine is of type
std::philox4x32, the 10000th consecutive invocation of it produces the value 1955073260 . -
If the default-constructed engine is of type
std::philox4x64, the 10000th consecutive invocation of it produces the value 3409172418970261260 .
2)
Constructs the engine with a seed value
value
. The engine's initial
state
is determined as follows:
[1]
- All elements of the sequence X are set to zero.
- The first element of the sequence K is set to value mod 2 w , the remaining elements are set to zero.
- The value of j is set to n - 1 .
3)
Constructs the engine with a seed sequence
seq
. The engine's initial
state
is determined as follows:
[1]
- All elements of the sequence X are set to zero.
- Given ( w - 1 ) / 32 + 1 as p , the elements of the sequence K are set by the following steps:
- Creates an invented array object a of length n / 2 * p .
- Calls seq. generate ( a + 0 , a + n / 2 * p ) .
-
For each integer
k
in
[ 0 ,n / 2), sets K k to (∑ p-1i=0 a k·p+i ·2 32i ) mod 2 w .
- The value of j is set to n - 1 .
This overload participates in overload resolution only if
SeedSeq
meets the requirements of
SeedSequence
.
4)
The copy constructor. Upon construction,
*
this
==
other
is
true
.
- ↑ 1.0 1.1 The buffer Y is intentionally not being set. As j is being set to n - 1 , the next state transition always generates new random values and stores them in Y .
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
See also
|
sets the current state of the engine
(public member function) |
|
|
sets the current counter of the engine
(public member function) |