std::philox_engine<UIntType,w,n,r,consts>::philox_engine

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Numerics library

Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array (valarray)
Pseudo-random number generation
Factor operations
gcd (C++17)	lcm (C++17)
Interpolations
midpoint (C++20)	lerp (C++20)
Saturation arithmetic
add_sat (C++26) sub_sat (C++26) saturate_cast (C++26)	mul_sat (C++26) div_sat (C++26)
Generic numeric operations
iota (C++11) ranges::iota (C++23) accumulate inner_product adjacent_difference partial_sum	reduce (C++17) transform_reduce (C++17) inclusive_scan (C++17) exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
Bit operations
has_single_bit (C++20)     bit_cast (C++20) bit_ceil (C++20) bit_floor (C++20) bit_width (C++20) rotl (C++20) rotr (C++20)	popcount (C++20) countl_zero (C++20) countl_one (C++20) countr_zero (C++20) countr_one (C++20) byteswap (C++23) endian (C++20)

 

Pseudo-random number generation

Uniform random bit generators   uniform_random_bit_generator (C++20) Random number engines linear_congruential_engine (C++11) mersenne_twister_engine (C++11) subtract_with_carry_engine (C++11) philox_engine (C++26) Random number engine adaptors discard_block_engine (C++11) independent_bits_engine (C++11) shuffle_order_engine (C++11) Predefined random number generators Non-deterministic random numbers random_device (C++11) Utilities generate_canonical (C++11) seed_seq (C++11) Random number algorithms ranges::generate_random (C++26) C random library rand    srand    RAND_MAX

Random number distributions Uniform distributions uniform_int_distribution (C++11) uniform_real_distribution (C++11) generate_canonical (C++11) Bernoulli distributions bernoulli_distribution (C++11) binomial_distribution (C++11) negative_binomial_distribution (C++11) geometric_distribution (C++11) Poisson distributions poisson_distribution (C++11) exponential_distribution (C++11) gamma_distribution (C++11) weibull_distribution (C++11) extreme_value_distribution (C++11) Normal distributions normal_distribution (C++11) lognormal_distribution (C++11) chi_squared_distribution (C++11) cauchy_distribution (C++11) fisher_f_distribution (C++11) student_t_distribution (C++11) Sampling distributions discrete_distribution (C++11) piecewise_constant_distribution (C++11) piecewise_linear_distribution (C++11)

 

std::philox_engine

Member functions

philox_engine::philox_engine

philox_engine::seed

philox_engine::set_counter

Generation

philox_engine::operator()

philox_engine::discard

Characteristics

philox_engine::min

philox_engine::max

Non-member functions

operator== (C++26)

operator<<operator>> (C++26)(C++26)

 

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:

• All elements of the sequence X are set to zero.
• The first element of the sequence K is set to \(\scriptsize value \mod 2^w \)value mod 2w
  , 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:

• 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:

1. Creates an invented array object a of length n / 2 * p.
2. Calls seq.generate(a + 0, a + n / 2 * p).
3. For each integer k in [​0​, n / 2), sets \(\scriptsize K_k \)K
   k to \(\scriptsize (\sum^{p-1}_{i=0} a_{k \cdot p+i} \cdot 2^{32i}) \mod 2^w \)(∑p-1
   i=0 a
   k·p+i·232i
   ) mod 2w
   .

• 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.

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

3) If SeedSeq is not std::seed_seq, throws the exceptions thrown by the seq.generate call.

See also

seed	sets the current state of the engine (public member function)
set_counter	sets the current counter of the engine (public member function)