SHiP::random::PhiloxRng Class Reference

#include <philox_rng.hpp>

Public Member Functions
	PhiloxRng (std::uint32_t seed, std::uint32_t key_hi=0xBEEFCAFE, std::uint64_t substream=0)
	key_hi selects an independent stream, so different generators seeded
double	uniform ()
	Uniform in [0, 1), with 32 bits of resolution.
double	uniform (double lo, double hi)
	Uniform in [lo, hi), with 32 bits of resolution.
double	uniform53 ()
	Uniform in [0, 1) with full double resolution: combines two consecutive 32-bit Philox words into a 64-bit integer and keeps the top 53 bits.
double	uniform53 (double lo, double hi)
	Uniform in [lo, hi) with full double resolution.
double	gaussian (double mean, double sigma, Precision precision=Precision::Bits32)
	Gaussian deviate by the Box–Muller transform, cosine branch only (two uniforms per deviate).
double	gamma_wh (double alpha, double scale=1, Precision precision=Precision::Bits32)
double	beta_dist_approx (double alpha, double zeta, Precision precision=Precision::Bits32)

Constructor & Destructor Documentation

PhiloxRng()

SHiP::random::PhiloxRng::PhiloxRng ( std::uint32_t  seed, std::uint32_t  key_hi = 0xBEEFCAFE, std::uint64_t  substream = 0  )

inlineexplicit

key_hi selects an independent stream, so different generators seeded

counter range. Use it for per-event sub-streams of one seed without perturbing the key (a key derived as seed ^ event would collide across seeds: XOR is not injective in (seed, event)).

Member Function Documentation

beta_dist_approx()

double SHiP::random::PhiloxRng::beta_dist_approx ( double  alpha, double  zeta, Precision  precision = Precision::Bits32  )

inline

gamma_wh()

double SHiP::random::PhiloxRng::gamma_wh ( double  alpha, double  scale = 1, Precision  precision = Precision::Bits32  )

inline

gaussian()

double SHiP::random::PhiloxRng::gaussian ( double  mean, double  sigma, Precision  precision = Precision::Bits32  )

inline

Gaussian deviate by the Box–Muller transform, cosine branch only (two uniforms per deviate).

The first draw is flipped from [0, 1) to (0, 1] to keep the log argument nonzero.

uniform() [1/2]

double SHiP::random::PhiloxRng::uniform ( )

inline

Uniform in [0, 1), with 32 bits of resolution.

uniform() [2/2]

double SHiP::random::PhiloxRng::uniform ( double  lo, double  hi  )

inline

Uniform in [lo, hi), with 32 bits of resolution.

uniform53() [1/2]

double SHiP::random::PhiloxRng::uniform53 ( )

inline

Uniform in [0, 1) with full double resolution: combines two consecutive 32-bit Philox words into a 64-bit integer and keeps the top 53 bits.

Use it when the sampled range spans many orders of magnitude (e.g. ps-scale jitter within a multi-second spill), where uniform() is too coarse. If only one word is left in the buffer, it is skipped.

uniform53() [2/2]

double SHiP::random::PhiloxRng::uniform53 ( double  lo, double  hi  )

inline

Uniform in [lo, hi) with full double resolution.

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The documentation for this class was generated from the following file:

• include/SHiP/random/philox_rng.hpp