fruit/libguf
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
libguf/src/guf_rand.h
jun ae7814fe7c Comment guf_rand
2025-03-29 16:16:06 +01:00

991 lines
36 KiB
C
Raw Blame History

/*
is parametrized: yes
*/
#if defined(GUF_RAND_IMPL_STATIC)
#define GUF_RAND_KWRDS static
#else
#define GUF_RAND_KWRDS
#endif
#ifndef GUF_RAND_H
#define GUF_RAND_H
#include "guf_common.h"
/*
- guf_rand32 functions use the xoshiro128** 1.1 generator [1] (rng-state of 4 32-bit integers, i.e. 128 bits)
- guf_rand64 functions use the xoshiro256** 1.0 generator [2] (rng-state of 4 64-bit integers, i.e. 256 bits)
- guf_rand functions use either guf_rand32 or guf_rand64 depending on GUF_RAND_32_BIT (which is set globally in guf_common.h depending on the platform's word-size)
[1] xoshiro128** 1.1 (public domain) written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
cf. https://prng.di.unimi.it/xoshiro128starstar.c (last-retrieved 2025-02-11)
[2] xoshiro256** 1.0 (public domain) written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
cf. https://prng.di.unimi.it/xoshiro256starstar.c (last-retrieved 2025-02-11)
*/
// State for xoshiro128** 1.1
typedef struct guf_rand32_state {
uint32_t s[4]; // Must not be all zero.
} guf_rand32_state;
// State for xoshiro256** 1.0
#ifdef UINT64_MAX
typedef struct guf_rand64_state {
uint64_t s[4]; // Must not be all zero.
} guf_rand64_state;
#endif
#ifdef GUF_RAND_32_BIT
// Use guf_rand32_state (i.e. xoshiro128** 1.1) as default.
#define GUF_RAND_MAX UINT32_MAX
typedef guf_rand32_state guf_randstate;
typedef uint32_t guf_rand_seed_t;
#else
// Use guf_rand64_state (i.e. xoshiro256** 1.0) as default.
#ifndef UINT64_MAX
#error "guf_rand.h: Platform does not support uint64_t (define GUF_RAND_32_BIT to fix)"
#endif
#define GUF_RAND_MAX UINT64_MAX
typedef guf_rand64_state guf_randstate;
typedef uint64_t guf_rand_seed_t;
#endif
/*
- guf_randstate_init(state, seed) -> void
Initialise the rng-state from a single 64-bit (or 32-bit) seed.
The seed is scrambled by guf_rand_splitmix64/32 internally.
Non-permissible states, i.e. states where all four state-integers turn out to be zero,
will be automatically corrected, which means all seeds passed to guf_randstate_init are permissible.
(If you want to initialise the guf_randstate struct manually, you have to ensure yourself the four state-integers aren't all zero.)
*/
GUF_RAND_KWRDS void guf_randstate_init(guf_randstate *state, guf_rand_seed_t seed);
#ifdef UINT64_MAX
GUF_RAND_KWRDS void guf_rand64_state_init(guf_rand64_state *state, uint64_t seed);
#endif
GUF_RAND_KWRDS void guf_rand32_state_init(guf_rand32_state *state, uint32_t seed);
/*
- guf_randstate_jump(state)
-> void; advance the rng-state as if 2^128 (or 2^64 for rand32_state) calls to guf_rand_u32 had occured.
Can be used to generate 2^128 (or 2^64 for rand32_state) non-overlapping subsequences for parallel computations.
*/
GUF_RAND_KWRDS void guf_randstate_jump(guf_randstate *state); // Equivalent to 2^128 (or 2^64) calls to guf_rand_u32
#ifdef UINT64_MAX
GUF_RAND_KWRDS void guf_rand64_state_jump(guf_rand64_state *state); // Equivalent to 2^128 calls to guf_rand64_u64
#endif
GUF_RAND_KWRDS void guf_rand32_state_jump(guf_rand32_state *state); // Equivalent to 2^64 calls to guf_rand32_u32
// Uniform distributions in default ranges:
/*
- guf_rand_splitmix64(state) -> uint64_t in range [0, UINT64_MAX]
(Very simple rng with only 64-bits of state; used for "scrambling" 64-bit seeds in guf_randstate_init.)
- guf_rand_splitmix32(state) -> uint32_t in range [0, UINT32_MAX]
(Very simple rng with only 32-bits of state; used for "scrambling" 32-bit seeds in guf_randstate_init.)
*/
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint64_t guf_rand_splitmix64(uint64_t *state);
#endif
GUF_RAND_KWRDS uint32_t guf_rand_splitmix32(uint32_t *state);
/*
- guf_rand_u32(state) -> uint32_t in range [0, UINT32_MAX]
*/
GUF_RAND_KWRDS uint32_t guf_rand_u32(guf_randstate *state);
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint32_t guf_rand64_u32(guf_rand64_state *state);
#endif
GUF_RAND_KWRDS uint32_t guf_rand32_u32(guf_rand32_state *state);
/*
- guf_rand_u64(state) -> uint64_t (or uint_least64_t) in range [0, UINT64_MAX]
NOTE: May be slow on 32-bit platforms.
NOTE: If uint64_t is not available (optional according to the standards), use uint_least64_t (always available in C99 and above).
*/
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint64_t guf_rand_u64(guf_randstate *state);
GUF_RAND_KWRDS uint64_t guf_rand32_u64(guf_rand32_state *state);
GUF_RAND_KWRDS uint64_t guf_rand64_u64(guf_rand64_state *state);
#else
GUF_RAND_KWRDS uint_least64_t guf_rand_u64(guf_randstate *state)
GUF_RAND_KWRDS uint_least64_t guf_rand32_u64(guf_rand32_state *state);
#endif
/*
- guf_rand_f64(state) -> double in range [0.0, 1.0)
NOTE: May be slow on 32-bit platforms (as it calls guf_rand_u64)
*/
GUF_RAND_KWRDS double guf_rand_f64(guf_randstate *state);
#ifdef UINT64_MAX
GUF_RAND_KWRDS double guf_rand64_f64(guf_rand64_state *state);
#endif
GUF_RAND_KWRDS double guf_rand32_f64(guf_rand32_state *state);
/*
- guf_rand_f32(state) -> float in range [0.f, 1.f)
*/
GUF_RAND_KWRDS float guf_rand_f32(guf_randstate *state);
#ifdef UINT64_MAX
GUF_RAND_KWRDS float guf_rand64_f32(guf_rand64_state *state);
#endif
GUF_RAND_KWRDS float guf_rand32_f32(guf_rand32_state *state);
// Uniform distributions in custom ranges:
/*
- guf_randrange_f32(state, min, end) -> float in range [min, end) (contrary to the integer equivalents, end is *not* inclusive)
- guf_randrange_f64(state, min, end) -> double in range [min, end) (contrary to the integer equivalents, end is *not* inclusive)
NOTE: f64 versions may be slow on 32-bit platforms.
*/
GUF_RAND_KWRDS float guf_randrange_f32(guf_randstate *state, float min, float end);
GUF_RAND_KWRDS double guf_randrange_f64(guf_randstate *state, double min, double end);
#ifdef UINT64_MAX
GUF_RAND_KWRDS float guf_rand64_range_f32(guf_rand64_state *state, float min, float end);
GUF_RAND_KWRDS double guf_rand64_range_f64(guf_rand64_state *state, double min, double end);
#endif
GUF_RAND_KWRDS float guf_rand32_range_f32(guf_rand32_state *state, float min, float end);
GUF_RAND_KWRDS double guf_rand32_range_f64(guf_rand32_state *state, double min, double end);
/*
- guf_randrange_i32(state, min, max) -> int32_t in range [min, max] (contrary to the float equivalents, max *is* inclusive)
- guf_randrange_u32(state, min, max) -> uint32_t in range [min, max] (contrary to the float equivalents, max *is* inclusive)
NOTE: guf_randrange_u32 may be slow on 32-bit platforms (as it calls guf_rand_f64).
This does not apply to guf_randrange_i32 (as it doesn't call guf_rand_f64).
*/
GUF_RAND_KWRDS int32_t guf_randrange_i32(guf_randstate *state, int32_t min, int32_t max);
GUF_RAND_KWRDS uint32_t guf_randrange_u32(guf_randstate *state, uint32_t min, uint32_t max); // NOTE: may be slow on 32-bit platforms.
#ifdef UINT64_MAX
GUF_RAND_KWRDS int32_t guf_rand64_range_i32(guf_rand64_state *state, int32_t min, int32_t max);
GUF_RAND_KWRDS uint32_t guf_rand64_range_u32(guf_rand64_state *state, uint32_t min, uint32_t max);
#endif
GUF_RAND_KWRDS int32_t guf_rand32_range_i32(guf_rand32_state *state, int32_t min, int32_t max);
GUF_RAND_KWRDS uint32_t guf_rand32_range_u32(guf_rand32_state *state, uint32_t min, uint32_t max); // NOTE: may be slow on 32-bit platforms.
/*
- guf_randrange_i64(state, min, max) -> int64_t in range [min, max] (contrary to the float equivalents, max *is* inclusive)
NOTE: The Generic version is only available if GUF_RAND_32_BIT is undefined and the platform supports uint64_t.
(The specific guf_rand64_range_i64 version is available as long as the platform supports uint64_t.)
*/
#if defined(UINT64_MAX) && !defined(GUF_RAND_32_BIT)
GUF_RAND_KWRDS int64_t guf_randrange_i64(guf_randstate *state, int64_t min, int64_t max);
#endif
#ifdef UINT64_MAX
GUF_RAND_KWRDS int64_t guf_rand64_range_i64(guf_rand64_state *state, int64_t min, int64_t max);
#endif
// Bernoulli-trials:
/*
- guf_rand_bernoulli_trial(state, p) -> return true with a probability of p, false with a probability of (1 - p)
NOTE: p will be clamped to be in range [0.0, 1.0]
NOTE: The f64 versions may be slow on 32-bit platforms.
- guf_rand_flip(state) -> return true with a probability of 50 %, i.e. fair coin flip (bernoulli trial with p == 0.5)
*/
GUF_RAND_KWRDS bool guf_rand_bernoulli_trial_f32(guf_randstate *state, float p);
GUF_RAND_KWRDS bool guf_rand_bernoulli_trial_f64(guf_randstate *state, double p);
GUF_RAND_KWRDS bool guf_rand_flip(guf_randstate *state);
#ifdef UINT64_MAX
GUF_RAND_KWRDS bool guf_rand64_bernoulli_trial_f32(guf_rand64_state *state, float p);
GUF_RAND_KWRDS bool guf_rand64_bernoulli_trial_f64(guf_rand64_state *state, double p);
GUF_RAND_KWRDS bool guf_rand64_flip(guf_rand64_state *state);
#endif
GUF_RAND_KWRDS bool guf_rand32_bernoulli_trial_f32(guf_rand32_state *state, float p);
GUF_RAND_KWRDS bool guf_rand32_bernoulli_trial_f64(guf_rand32_state *state, double p);
GUF_RAND_KWRDS bool guf_rand32_flip(guf_rand32_state *state);
// Normal distributions:
/*
- guf_rand_normal_sample_f32/f64(state, mean, std_dev, result, n)
-> void; put n float/double samples following the given normal-distribution into result (result is allocated by the caller and must have enough space to hold at least n samples)
- guf_rand_normal_sample_one_f32/f64(state, mean, std_dev)
-> return one float/double sample following the given normal-distribution
- NOTE: the f64 versions may be slow on 32-bit platforms.
*/
GUF_RAND_KWRDS void guf_rand_normal_sample_f64(guf_randstate *state, double mean, double std_dev, double *result, ptrdiff_t n);
GUF_RAND_KWRDS void guf_rand_normal_sample_f32(guf_randstate *state, float mean, float std_dev, float *result, ptrdiff_t n);
GUF_RAND_KWRDS double guf_rand_normal_sample_one_f64(guf_randstate *state, double mean, double std_dev);
GUF_RAND_KWRDS float guf_rand_normal_sample_one_f32(guf_randstate *state, float mean, float std_dev);
#ifdef UINT64_MAX
GUF_RAND_KWRDS void guf_rand64_normal_sample_f32(guf_rand64_state *state, float mean, float std_dev, float *result, ptrdiff_t n);
GUF_RAND_KWRDS void guf_rand64_normal_sample_f64(guf_rand64_state *state, double mean, double std_dev, double *result, ptrdiff_t n);
GUF_RAND_KWRDS float guf_rand64_normal_sample_one_f32(guf_rand64_state *state, float mean, float std_dev);
GUF_RAND_KWRDS double guf_rand64_normal_sample_one_f64(guf_rand64_state *state, double mean, double std_dev);
#endif
GUF_RAND_KWRDS void guf_rand32_normal_sample_f32(guf_rand32_state *state, float mean, float std_dev, float *result, ptrdiff_t n);
GUF_RAND_KWRDS void guf_rand32_normal_sample_f64(guf_rand32_state *state, double mean, double std_dev, double *result, ptrdiff_t n);
GUF_RAND_KWRDS float guf_rand32_normal_sample_one_f32(guf_rand32_state *state, float mean, float std_dev);
GUF_RAND_KWRDS double guf_rand32_normal_sample_one_f64(guf_rand32_state *state, double mean, double std_dev);
#endif
#if defined(GUF_RAND_IMPL) || defined(GUF_RAND_IMPL_STATIC)
#include <math.h>
#include <float.h>
#include "guf_common.h"
#include "guf_assert.h"
#include "guf_math.h"
#ifdef UINT64_MAX
/*
splitmix64 written in 2015 by Sebastiano Vigna (vigna@acm.org) (released as public domain)
cf. https://prng.di.unimi.it/splitmix64.c (last-retrieved 2025-02-11)
*/
GUF_RAND_KWRDS uint64_t guf_rand_splitmix64(uint64_t *state)
{
GUF_ASSERT(state);
uint64_t z = ((*state) += 0x9e3779b97f4a7c15);
z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
return z ^ (z >> 31);
}
#endif
/*
splitmix32 written in 2016 by Kaito Udagawa (released under CC0 <http://creativecommons.org/publicdomain/zero/1.0/>)
cf. https://github.com/umireon/my-random-stuff/blob/master/xorshift/splitmix32.c (last-retrieved 2025-03-28)
*/
GUF_RAND_KWRDS uint32_t guf_rand_splitmix32(uint32_t *state)
{
GUF_ASSERT(state);
uint32_t z = (*state += 0x9e3779b9);
z = (z ^ (z >> 16)) * 0x85ebca6b;
z = (z ^ (z >> 13)) * 0xc2b2ae35;
return z ^ (z >> 16);
}
GUF_RAND_KWRDS void guf_rand32_state_init(guf_rand32_state *state, uint32_t seed)
{
for (size_t i = 0; i < GUF_ARR_SIZE(state->s); ++i) {
state->s[i] = guf_rand_splitmix32(&seed);
}
if (!state->s[0] && !state->s[1] && !state->s[2] && !state->s[3]) { // State must not be only zeroes:
state->s[0] = 0x9e3779b9; // arbitrary constant != 0
seed = state->s[0];
for (size_t i = 1; i < GUF_ARR_SIZE(state->s); ++i) {
state->s[i] = guf_rand_splitmix32(&seed);
}
}
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS void guf_rand64_state_init(guf_rand64_state *state, uint64_t seed)
{
for (size_t i = 0; i < GUF_ARR_SIZE(state->s); ++i) {
state->s[i] = guf_rand_splitmix64(&seed);
}
if (!state->s[0] && !state->s[1] && !state->s[2] && !state->s[3]) { // State must not be only zeroes:
state->s[0] = 0x9e3779b97f4a7c15; // arbitrary constant != 0
seed = state->s[0];
for (size_t i = 1; i < GUF_ARR_SIZE(state->s); ++i) {
state->s[i] = guf_rand_splitmix64(&seed);
}
}
}
#endif
GUF_RAND_KWRDS void guf_randstate_init(guf_randstate *state, guf_rand_seed_t seed)
{
#ifdef GUF_RAND_32_BIT
guf_rand32_state_init(state, seed);
#else
guf_rand64_state_init(state, seed);
#endif
}
GUF_RAND_KWRDS uint32_t guf_rand32_u32(guf_rand32_state *state)
{
GUF_ASSERT(state);
GUF_ASSERT(state->s[0] || state->s[1] || state->s[2] || state->s[3]);
/*
xoshiro128** 1.1 (public domain) written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
cf. https://prng.di.unimi.it/xoshiro128starstar.c (last-retrieved 2025-02-11)
*/
const uint32_t result = guf_rotl_u32(state->s[1] * 5, 7) * 9;
const uint32_t t = state->s[1] << 9;
state->s[2] ^= state->s[0];
state->s[3] ^= state->s[1];
state->s[1] ^= state->s[2];
state->s[0] ^= state->s[3];
state->s[2] ^= t;
state->s[3] = guf_rotl_u32(state->s[3], 11);
return result;
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint32_t guf_rand64_u32(guf_rand64_state *state)
{
return (uint32_t)(guf_rand64_u64(state) >> 32);
}
#endif
GUF_RAND_KWRDS uint32_t guf_rand_u32(guf_randstate *state)
{
GUF_ASSERT(state);
GUF_ASSERT(state->s[0] || state->s[1] || state->s[2] || state->s[3]);
#ifdef GUF_RAND_32_BIT
return guf_rand32_u32(state);
#else
return guf_rand64_u32(state);
#endif
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint64_t guf_rand64_u64(guf_rand64_state *state)
{
GUF_ASSERT(state);
GUF_ASSERT(state->s[0] || state->s[1] || state->s[2] || state->s[3]);
/*
xoshiro256** 1.0 (public domain) written in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org)
cf. https://prng.di.unimi.it/xoshiro256starstar.c (last-retrieved 2025-02-11)
*/
const uint64_t result = guf_rotl_u64(state->s[1] * 5, 7) * 9;
const uint64_t t = state->s[1] << 17;
state->s[2] ^= state->s[0];
state->s[3] ^= state->s[1];
state->s[1] ^= state->s[2];
state->s[0] ^= state->s[3];
state->s[2] ^= t;
state->s[3] = guf_rotl_u64(state->s[3], 45);
return result;
}
#endif
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint64_t guf_rand32_u64(guf_rand32_state *state)
#else
GUF_RAND_KWRDS uint_least64_t guf_rand32_u64(guf_rand32_state *state)
#endif
{
GUF_ASSERT(state);
GUF_ASSERT(state->s[0] || state->s[1] || state->s[2] || state->s[3]);
const uint32_t lower_bits = guf_rand32_u32(state);
const uint32_t upper_bits = guf_rand32_u32(state);
#ifdef UINT64_MAX
return ((uint64_t)upper_bits << 32) | (uint64_t)lower_bits; // TODO: not sure if that's a good idea...
#else
return ((uint_least64_t)upper_bits << 32) | (uint_least64_t)lower_bits; // TODO: not sure if that's a good idea...
#endif
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint64_t guf_rand_u64(guf_randstate *state)
#else
GUF_RAND_KWRDS uint_least64_t guf_rand_u64(guf_randstate *state)
#endif
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_u64(state);
#else
return guf_rand64_u64(state);
#endif
}
/*
Equivalent to 2^64 calls to guf_rand32_u32; can be used to generate 2^64
non-overlapping subsequences for parallel computations.
*/
GUF_RAND_KWRDS void guf_rand32_state_jump(guf_rand32_state *state)
{
GUF_ASSERT(state);
static const uint32_t JUMP[] = { 0x8764000b, 0xf542d2d3, 0x6fa035c3, 0x77f2db5b };
uint32_t s0 = 0;
uint32_t s1 = 0;
uint32_t s2 = 0;
uint32_t s3 = 0;
for (size_t i = 0; i < sizeof JUMP / sizeof *JUMP; ++i) {
for (int b = 0; b < 32; ++b) {
if (JUMP[i] & UINT32_C(1) << b) {
s0 ^= state->s[0];
s1 ^= state->s[1];
s2 ^= state->s[2];
s3 ^= state->s[3];
}
guf_rand32_u32(state);
}
}
state->s[0] = s0;
state->s[1] = s1;
state->s[2] = s2;
state->s[3] = s3;
}
#ifdef UINT64_MAX
/*
Equivalent to 2^128 calls to guf_rand64_u64(); can be used to generate 2^128
non-overlapping subsequences for parallel computations.
*/
GUF_RAND_KWRDS void guf_rand64_state_jump(guf_rand64_state *state)
{
static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
uint64_t s0 = 0;
uint64_t s1 = 0;
uint64_t s2 = 0;
uint64_t s3 = 0;
for (size_t i = 0; i < sizeof JUMP / sizeof *JUMP; ++i) {
for (int b = 0; b < 64; ++b) {
if (JUMP[i] & UINT64_C(1) << b) {
s0 ^= state->s[0];
s1 ^= state->s[1];
s2 ^= state->s[2];
s3 ^= state->s[3];
}
guf_rand64_u64(state);
}
}
state->s[0] = s0;
state->s[1] = s1;
state->s[2] = s2;
state->s[3] = s3;
}
#endif
/*
Equivalent to 2^128 calls to guf_rand() (or 2^64 calls if GUF_RAND_32_BIT); it can be used to generate 2^128 (or 2^64)
non-overlapping subsequences for parallel computations.
*/
GUF_RAND_KWRDS void guf_randstate_jump(guf_randstate *state)
{
GUF_ASSERT(state);
#ifdef GUF_RAND_32_BIT
guf_rand32_state_jump(state);
#else
guf_rand64_state_jump(state);
#endif
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS double guf_rand64_f64(guf_rand64_state *state)
{
// cf. https://prng.di.unimi.it/ and https://dotat.at/@/2023-06-23-random-double.html (last-retrieved 2025-02-11)
return (guf_rand64_u64(state) >> 11) * 0x1.0p-53; // 11 == 64 - 53 (double has a 53-bit mantissa/significand)
}
#endif
GUF_RAND_KWRDS double guf_rand32_f64(guf_rand32_state *state)
{
// cf. https://prng.di.unimi.it/ and https://dotat.at/@/2023-06-23-random-double.html (last-retrieved 2025-02-11)
return (guf_rand32_u64(state) >> 11) * 0x1.0p-53; // 11 == 64 - 53 (double has a 53-bit mantissa/significand)
}
// Generate double in the unit interval [0, 1)
GUF_RAND_KWRDS double guf_rand_f64(guf_randstate *state)
{
// cf. https://prng.di.unimi.it/ and https://dotat.at/@/2023-06-23-random-double.html (last-retrieved 2025-02-11)
return (guf_rand_u64(state) >> 11) * 0x1.0p-53; // 11 == 64 - 53 (double has a 53-bit mantissa/significand)
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS float guf_rand64_f32(guf_rand64_state *state)
{
return (guf_rand64_u64(state) >> 40) * 0x1.0p-24f; // 40 == 64 - 24; (float has a 24-bit mantissa/significand)
}
#endif
GUF_RAND_KWRDS float guf_rand32_f32(guf_rand32_state *state)
{
return (guf_rand32_u32(state) >> 8) * 0x1.0p-24f; // 8 == 32 - 24; (float has a 24-bit mantissa/significand)
}
// Generate float in the unit interval [0, 1)
GUF_RAND_KWRDS float guf_rand_f32(guf_randstate *state)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_f32(state);
#else
return guf_rand64_f32(state);
#endif
}
GUF_RAND_KWRDS bool guf_rand32_bernoulli_trial_f32(guf_rand32_state *state, float p)
{
p = guf_clamp_f32(p, 0, 1);
return guf_rand32_f32(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS bool guf_rand64_bernoulli_trial_f32(guf_rand64_state *state, float p)
{
p = guf_clamp_f32(p, 0, 1);
return guf_rand64_f32(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
#endif
GUF_RAND_KWRDS bool guf_rand_bernoulli_trial_f32(guf_randstate *state, float p)
{
p = guf_clamp_f32(p, 0, 1);
return guf_rand_f32(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
GUF_RAND_KWRDS bool guf_rand32_bernoulli_trial_f64(guf_rand32_state *state, double p)
{
p = guf_clamp_f64(p, 0, 1);
return guf_rand32_f64(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS bool guf_rand64_bernoulli_trial_f64(guf_rand64_state *state, double p)
{
p = guf_clamp_f64(p, 0, 1);
return guf_rand64_f64(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
#endif
GUF_RAND_KWRDS bool guf_rand_bernoulli_trial_f64(guf_randstate *state, double p)
{
p = guf_clamp_f64(p, 0, 1);
return guf_rand_f64(state) < p; // never true for p = 0, always true for p = 1 since guf_rand_f64 is in range [0, 1)
}
GUF_RAND_KWRDS bool guf_rand32_flip(guf_rand32_state *state)
{
return guf_rand32_bernoulli_trial_f32(state, 0.5f);
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS bool guf_rand64_flip(guf_rand64_state *state)
{
return guf_rand64_bernoulli_trial_f64(state, 0.5);
}
#endif
GUF_RAND_KWRDS bool guf_rand_flip(guf_randstate *state)
{
#ifdef GUF_RAND_32_BIT
return guf_rand_bernoulli_trial_f32(state, 0.5f);
#else
return guf_rand_bernoulli_trial_f64(state, 0.5);
#endif
}
GUF_RAND_KWRDS double guf_rand32_range_f64(guf_rand32_state *state, double min, double end)
{
if (min == (double)INFINITY) {
min = DBL_MAX;
} else if (min == (double)-INFINITY) {
min = -DBL_MAX;
}
if (end == (double)INFINITY) {
end = DBL_MAX;
} else if (end == (double)-INFINITY) {
end = -DBL_MAX;
}
GUF_ASSERT_RELEASE(end >= min);
return guf_rand32_f64(state) * (end - min) + min;
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS double guf_rand64_range_f64(guf_rand64_state *state, double min, double end)
{
if (min == (double)INFINITY) {
min = DBL_MAX;
} else if (min == (double)-INFINITY) {
min = -DBL_MAX;
}
if (end == (double)INFINITY) {
end = DBL_MAX;
} else if (end == (double)-INFINITY) {
end = -DBL_MAX;
}
GUF_ASSERT_RELEASE(end >= min);
return guf_rand64_f64(state) * (end - min) + min;
}
#endif
// returns uniformly-distributed random double in range [min, end) (or min if min == end)
GUF_RAND_KWRDS double guf_randrange_f64(guf_randstate *state, double min, double end)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_range_f64(state, min, end);
#else
return guf_rand64_range_f64(state, min, end);
#endif
}
// returns uniformly-distributed random float in range [min, end) (or min if min == end)
GUF_RAND_KWRDS float guf_rand32_range_f32(guf_rand32_state *state, float min, float end)
{
if (min == INFINITY) {
min = FLT_MAX;
} else if (min == -INFINITY) {
min = -FLT_MAX;
}
if (end == INFINITY) {
end = FLT_MAX;
} else if (end == -INFINITY) {
end = -FLT_MAX;
}
GUF_ASSERT_RELEASE(end >= min);
return guf_rand32_f32(state) * (end - min) + min;
}
#ifdef UINT64_MAX
// returns uniformly-distributed random float in range [min, end) (or min if min == end)
GUF_RAND_KWRDS float guf_rand64_range_f32(guf_rand64_state *state, float min, float end)
{
if (min == INFINITY) {
min = FLT_MAX;
} else if (min == -INFINITY) {
min = -FLT_MAX;
}
if (end == INFINITY) {
end = FLT_MAX;
} else if (end == -INFINITY) {
end = -FLT_MAX;
}
GUF_ASSERT_RELEASE(end >= min);
return guf_rand64_f32(state) * (end - min) + min;
}
#endif
// returns uniformly-distributed random float in range [min, end) (or min if min == end)
GUF_RAND_KWRDS float guf_randrange_f32(guf_randstate *state, float min, float end)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_range_f32(state, min, end);
#else
return guf_rand64_range_f32(state, min, end);
#endif
}
#ifdef UINT64_MAX
// returns uniformly-distributed random int32_t in range [min, max] (max is inclusive as opposed to the f32/f64 versions)
GUF_RAND_KWRDS int32_t guf_rand64_range_i32(guf_rand64_state *state, int32_t min, int32_t max)
{
GUF_ASSERT_RELEASE(max >= min);
if (min == max) {
return min;
}
const double delta = (double)max - (double)min;
// cf. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random (last-retrieved 2025-02-12)
const double result = floor(guf_rand64_f64(state) * (delta + 1.0) + min);
GUF_ASSERT(result >= min && result <= max);
return (int32_t)result;
}
#endif
// returns uniformly-distributed random int32_t in range [min, max] (max is inclusive as opposed to the f32/f64 versions)
GUF_RAND_KWRDS int32_t guf_rand32_range_i32(guf_rand32_state *state, int32_t min, int32_t max)
{
GUF_ASSERT_RELEASE(max >= min);
if (min == max) {
return min;
}
const uint32_t rand_max_i32 = UINT32_MAX >> 1; // 2^31 - 1 (== INT32_MAX)
const uint32_t delta = guf_absdiff_i32(max, min);
if (delta > rand_max_i32) {
guf_panic(GUF_ERR_INT_OVERFLOW, GUF_ERR_MSG("in function guf_rand32_range_i32: interval [min, max] larger than INT32_MAX"));
return -1;
}
/*
We don't use the same approach as in guf_rand64_range_i32 because a 32-bit float only has a 24-bit mantissa
(and using double like in guf_rand64_range_i32 would require 64-bit arithmetic due to guf_rand32_f64).
cf. https://c-faq.com/lib/randrange.html (last-retrieved 2025-02-11)
https://stackoverflow.com/a/6852396 (last-retrieved 2025-02-11)
*/
const uint32_t num_rand_vals = rand_max_i32 + 1u; // 2^31
const uint32_t num_bins = (delta + 1u);
const uint32_t bin_size = num_rand_vals / num_bins; // bin_size = floor(num_rand_vals / num_bins)
const uint32_t limit = num_rand_vals - (num_rand_vals % num_bins); // limit == bin_size * num_bins
GUF_ASSERT(limit == bin_size * num_bins);
/*
since (num_rand_vals % num_bins) is at most 2^30 + 1 (I think...), the minimum limit is 2^31 - (2^30 + 1),
which means in the worst case, the chance of having to iterate (i.e. step >= limit)
is 1 - (2^31 - (2^30 + 1)) / 2^31 == 0.5
*/
uint32_t step;
do {
step = guf_rand32_u32(state) >> 1; // [0, 2^31 - 1]
} while (step >= limit);
step = step / bin_size;
GUF_ASSERT(!guf_add_is_overflow_i32(min, step));
const int32_t rnd = min + (int32_t)step;
GUF_ASSERT(rnd >= min && rnd <= max);
return rnd;
}
// returns uniformly-distributed random int32_t in range [min, max] (max is inclusive as opposed to the f32/f64 versions)
GUF_RAND_KWRDS int32_t guf_randrange_i32(guf_randstate *state, int32_t min, int32_t max)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_range_i32(state, min, max);
#else
return guf_rand64_range_i32(state, min, max);
#endif
}
GUF_RAND_KWRDS uint32_t guf_rand32_range_u32(guf_rand32_state *state, uint32_t min, uint32_t max)
{
/*
The method used in guf_rand32_range_i32 above (which uses only 32-bit integer arithmetic) could overflow here,
so we use the floating-point method since we have to use 64-bit arithmetic anyways.
*/
GUF_ASSERT_RELEASE(max >= min);
if (min == max) {
return min;
}
const double delta = (double)max - (double)min;
const double result = floor(guf_rand32_f64(state) * (delta + 1.0) + min); // NOTE: guf_rand32_f64 is slow for 32-bit platforms...
GUF_ASSERT(result >= min && result <= max);
return (uint32_t)result;
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS uint32_t guf_rand64_range_u32(guf_rand64_state *state, uint32_t min, uint32_t max)
{
GUF_ASSERT_RELEASE(max >= min);
if (min == max) {
return min;
}
const double delta = (double)max - (double)min;
const double result = floor(guf_rand64_f64(state) * (delta + 1.0) + min);
GUF_ASSERT(result >= min && result <= max);
return (uint32_t)result;
}
#endif
GUF_RAND_KWRDS uint32_t guf_randrange_u32(guf_randstate *state, uint32_t min, uint32_t max)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_range_u32(state, min, max);
#else
return guf_rand64_range_u32(state, min, max);
#endif
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS int64_t guf_rand64_range_i64(guf_rand64_state *state, int64_t min, int64_t max)
{
GUF_ASSERT_RELEASE(max >= min);
if (min == max) {
return min;
}
const uint64_t rand_max_i64 = UINT64_MAX >> 1; // 2^63 - 1 (== INT64_MAX)
const uint64_t delta = guf_absdiff_i64(max, min);
if (delta > rand_max_i64) {
guf_panic(GUF_ERR_INT_OVERFLOW, GUF_ERR_MSG("in function guf_randrange_i64: interval [min, max] larger than INT64_MAX"));
return -1;
}
/*
We should not use the same approach as in guf_rand64_range_i32 because (max - min) might be close to 2^63 - 1
cf. https://c-faq.com/lib/randrange.html (last-retrieved 2025-02-11)
https://stackoverflow.com/a/6852396 (last-retrieved 2025-02-11)
*/
const uint64_t num_rand_vals = rand_max_i64 + 1u; // 2^63
const uint64_t num_bins = (delta + 1u);
const uint64_t bin_size = num_rand_vals / num_bins; // bin_size = floor(num_rand_vals / num_bins)
const uint64_t limit = num_rand_vals - (num_rand_vals % num_bins); // limit == bin_size * num_bins
GUF_ASSERT(limit == bin_size * num_bins);
/*
since (num_rand_vals % num_bins) is at most 2^62 + 1 (I think...), the minimum limit is 2^63 - (2^62 + 1),
which means in the worst case, the chance of having to iterate (i.e. step >= limit)
is 1 - (2^63 - (2^62 + 1)) / 2^63 == 0.5
*/
uint64_t step;
do {
step = guf_rand64_u64(state) >> 1; // [0, 2^63 - 1]
} while (step >= limit);
step = step / bin_size;
GUF_ASSERT(!guf_add_is_overflow_i64(min, step));
const int64_t rnd = min + (int64_t)step;
GUF_ASSERT(rnd >= min && rnd <= max);
return rnd;
}
#endif
#if !defined(GUF_RAND_32_BIT) && defined(UINT64_MAX)
// returns uniformly-distributed random int64_t in range [min, max] (max is inclusive as opposed to the f32/f64 versions)
GUF_RAND_KWRDS int64_t guf_randrange_i64(guf_randstate *state, int64_t min, int64_t max)
{
return guf_rand64_range_i64(state, min, max);
}
#endif
// Box-Müller-transform transcribed from wikipedia, cf. https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform (last-retrieved 2025-02-12)
GUF_RAND_KWRDS void guf_rand32_normal_sample_f64(guf_rand32_state *state, double mean, double std_dev, double *result, ptrdiff_t n)
{
GUF_ASSERT_RELEASE(result);
GUF_ASSERT_RELEASE(n >= 0);
const double TAU = 2.0 * GUF_PI;
ptrdiff_t i = 0;
while (i < n) {
double u1, u2;
do {
u1 = guf_rand32_f64(state);
} while (u1 == 0);
u2 = guf_rand32_f64(state);
const double mag = std_dev * sqrt(-2.0 * log(u1));
result[i++] = mag * cos(TAU * u2) + mean;
if (i < n) {
result[i++] = mag * sin(TAU * u2) + mean;
}
}
}
#ifdef UINT64_MAX
// Box-Müller-transform transcribed from wikipedia, cf. https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform (last-retrieved 2025-02-12)
GUF_RAND_KWRDS void guf_rand64_normal_sample_f64(guf_rand64_state *state, double mean, double std_dev, double *result, ptrdiff_t n)
{
GUF_ASSERT_RELEASE(result);
GUF_ASSERT_RELEASE(n >= 0);
const double TAU = 2.0 * GUF_PI;
ptrdiff_t i = 0;
while (i < n) {
double u1, u2;
do {
u1 = guf_rand64_f64(state);
} while (u1 == 0);
u2 = guf_rand64_f64(state);
const double mag = std_dev * sqrt(-2.0 * log(u1));
result[i++] = mag * cos(TAU * u2) + mean;
if (i < n) {
result[i++] = mag * sin(TAU * u2) + mean;
}
}
}
#endif
// Box-Müller-transform transcribed from wikipedia, cf. https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform (last-retrieved 2025-02-12)
GUF_RAND_KWRDS void guf_rand_normal_sample_f64(guf_randstate *state, double mean, double std_dev, double *result, ptrdiff_t n)
{
#ifdef GUF_RAND_32_BIT
guf_rand32_normal_sample_f64(state, mean, std_dev, result, n);
#else
guf_rand64_normal_sample_f64(state, mean, std_dev, result, n);
#endif
}
GUF_RAND_KWRDS void guf_rand32_normal_sample_f32(guf_rand32_state *state, float mean, float std_dev, float *result, ptrdiff_t n)
{
GUF_ASSERT_RELEASE(result);
GUF_ASSERT_RELEASE(n >= 0);
const float TAU = 2.f * (float)GUF_PI;
ptrdiff_t i = 0;
while (i < n) {
float u1, u2;
do {
u1 = guf_rand32_f32(state);
} while (u1 == 0);
u2 = guf_rand32_f32(state);
const float mag = std_dev * sqrtf(-2.f * logf(u1));
result[i++] = mag * cosf(TAU * u2) + mean;
if (i < n) {
result[i++] = mag * sinf(TAU * u2) + mean;
}
}
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS void guf_rand64_normal_sample_f32(guf_rand64_state *state, float mean, float std_dev, float *result, ptrdiff_t n)
{
GUF_ASSERT_RELEASE(result);
GUF_ASSERT_RELEASE(n >= 0);
const float TAU = 2.f * (float)GUF_PI;
ptrdiff_t i = 0;
while (i < n) {
float u1, u2;
do {
u1 = guf_rand64_f32(state);
} while (u1 == 0);
u2 = guf_rand64_f32(state);
const float mag = std_dev * sqrtf(-2.f * logf(u1));
result[i++] = mag * cosf(TAU * u2) + mean;
if (i < n) {
result[i++] = mag * sinf(TAU * u2) + mean;
}
}
}
#endif
GUF_RAND_KWRDS void guf_rand_normal_sample_f32(guf_randstate *state, float mean, float std_dev, float *result, ptrdiff_t n)
{
#ifdef GUF_RAND_32_BIT
guf_rand32_normal_sample_f32(state, mean, std_dev, result, n);
#else
guf_rand64_normal_sample_f32(state, mean, std_dev, result, n);
#endif
}
GUF_RAND_KWRDS double guf_rand32_normal_sample_one_f64(guf_rand32_state *state, double mean, double std_dev)
{
double result;
guf_rand32_normal_sample_f64(state, mean, std_dev, &result, 1);
return result;
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS double guf_rand64_normal_sample_one_f64(guf_rand64_state *state, double mean, double std_dev)
{
double result;
guf_rand64_normal_sample_f64(state, mean, std_dev, &result, 1);
return result;
}
#endif
GUF_RAND_KWRDS double guf_rand_normal_sample_one_f64(guf_randstate *state, double mean, double std_dev)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_normal_sample_one_f64(state, mean, std_dev);
#else
return guf_rand64_normal_sample_one_f64(state, mean, std_dev);
#endif
}
GUF_RAND_KWRDS float guf_rand32_normal_sample_one_f32(guf_rand32_state *state, float mean, float std_dev)
{
float result;
guf_rand32_normal_sample_f32(state, mean, std_dev, &result, 1);
return result;
}
#ifdef UINT64_MAX
GUF_RAND_KWRDS float guf_rand64_normal_sample_one_f32(guf_rand64_state *state, float mean, float std_dev)
{
float result;
guf_rand64_normal_sample_f32(state, mean, std_dev, &result, 1);
return result;
}
#endif
GUF_RAND_KWRDS float guf_rand_normal_sample_one_f32(guf_randstate *state, float mean, float std_dev)
{
#ifdef GUF_RAND_32_BIT
return guf_rand32_normal_sample_one_f32(state, mean, std_dev);
#else
return guf_rand64_normal_sample_one_f32(state, mean, std_dev);
#endif
}
#undef GUF_RAND_IMPL
#undef GUF_RAND_IMPL_STATIC
#endif /* end impl */
#undef GUF_RAND_KWRDS
Reference in New Issue View Git Blame Copy Permalink