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rand: reorganize (step 1)

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Hungry Blue Dev 2020-06-02 00:43:56 +05:30 committed by GitHub
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19 changed files with 3833 additions and 160 deletions
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15
vlib/hash/wyhash/rand.v
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@ -1,15 +0,0 @@
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module wyhash
pub fn rand_u64(seed &u64) u64 {
mut seed0 := seed
unsafe{
mut seed1 := *seed0
seed1 += wyp0
*seed0 = seed1
return wymum(seed1^wyp1, seed1)
}
return 0
}

2
vlib/hash/wyhash/wyhash.v
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@ -92,7 +92,7 @@ fn wyrotr(v u64, k u32) u64 {
}
[inline]
fn wymum(a, b u64) u64 {
pub fn wymum(a, b u64) u64 {
/*
mut r := u128(a)
r = r*b

13
vlib/hash/wyhash/wyhash_test.v
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@ -27,16 +27,3 @@ fn test_wyhash() {
assert got == test.expected
}
}
fn test_rand_u64() {
seed := u64(111)
mut rand_nos := []u64{}
for _ in 0..40 {
rand_no := wyhash.rand_u64(&seed)
for r in rand_nos {
assert rand_no != r
}
rand_nos << rand_no
}
assert true
}

320
vlib/rand/mt19937.v Normal file
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@ -0,0 +1,320 @@
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
import math.bits
/*
C++ functions for MT19937, with initialization improved 2002/2/10.
Coded by Takuji Nishimura and Makoto Matsumoto.
This is a faster version by taking Shawn Cokus's optimization,
Matthe Bellew's simplification, Isaku Wada's real version.
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The names of its contributors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Any feedback is very welcome.
http://www.math.keio.ac.jp/matumoto/emt.html
email: matumoto@math.keio.ac.jp
*/
const (
nn = 312
mm = 156
matrix_a = 0xB5026F5AA96619E9
um = 0xFFFFFFFF80000000
lm = 0x7FFFFFFF
inv_f64_limit = 1.0 / 9007199254740992.0
)
// A generator that uses the Mersenne Twister algorithm with period 2^19937
pub struct MT19937RNG {
mut:
state []u64 = calculate_state(time_seed_array(2), mut []u64{len: nn})
mti int = nn
next_rnd u32 = 0
has_next bool = false
}
fn calculate_state(seed_data []u32, mut state []u64) []u64 {
lo := u64(seed_data[0])
hi := u64(seed_data[1])
state[0] = u64((hi << 32) | lo)
for j := 1; j < nn; j++ {
state[j] = u64(6364136223846793005) * (state[j - 1] ^ (state[j - 1] >> 62)) + u64(j)
}
return state
}
// seed() - Set the seed, needs only two u32s in little endian format as [lower, higher]
pub fn (mut rng MT19937RNG) seed(seed_data []u32) {
if seed_data.len != 2 {
eprintln('mt19937 needs only two 32bit integers as seed: [lower, higher]')
exit(1)
}
rng.state = calculate_state(seed_data, mut rng.state)
rng.mti = nn
rng.next_rnd = 0
rng.has_next = false
}
// rng.u32() - return a pseudorandom 32bit int in [0, 2**32)
[inline]
pub fn (mut rng MT19937RNG) u32() u32 {
if rng.has_next {
rng.has_next = false
return rng.next_rnd
}
ans := rng.u64()
rng.next_rnd = u32(ans >> 32)
rng.has_next = true
return u32(ans & 0xffffffff)
}
// rng.u64() - return a pseudorandom 64bit int in [0, 2**64)
[inline]
pub fn (mut rng MT19937RNG) u64() u64 {
mag01 := [u64(0), u64(matrix_a)]
mut x := u64(0)
mut i := int(0)
if rng.mti >= nn {
for i = 0; i < nn - mm; i++ {
x = (rng.state[i] & um) | (rng.state[i + 1] & lm)
rng.state[i] = rng.state[i + mm] ^ (x >> 1) ^ mag01[int(x & 1)]
}
for i < nn - 1 {
x = (rng.state[i] & um) | (rng.state[i + 1] & lm)
rng.state[i] = rng.state[i + (mm - nn)] ^ (x >> 1) ^ mag01[int(x & 1)]
i++
}
x = (rng.state[nn - 1] & um) | (rng.state[0] & lm)
rng.state[nn - 1] = rng.state[mm - 1] ^ (x >> 1) ^ mag01[int(x & 1)]
rng.mti = 0
}
x = rng.state[rng.mti]
rng.mti++
x ^= (x >> 29) & 0x5555555555555555
x ^= (x << 17) & 0x71D67FFFEDA60000
x ^= (x << 37) & 0xFFF7EEE000000000
x ^= (x >> 43)
return x
}
// rng.int() - return a 32-bit signed (possibly negative) int
[inline]
pub fn (mut rng MT19937RNG) int() int {
return int(rng.u32())
}
// rng.i64() - return a 64-bit signed (possibly negative) i64
[inline]
pub fn (mut rng MT19937RNG) i64() i64 {
return i64(rng.u64())
}
// rng.int31() - return a 31bit positive pseudorandom integer
[inline]
pub fn (mut rng MT19937RNG) int31() int {
return int(rng.u32() >> 1)
}
// rng.int63() - return a 63bit positive pseudorandom integer
[inline]
pub fn (mut rng MT19937RNG) int63() i64 {
return i64(rng.u64() >> 1)
}
// rng.u32n(max) - return a 32bit u32 in [0, max)
[inline]
pub fn (mut rng MT19937RNG) u32n(max u32) u32 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
// Check SysRNG in system_rng.c.v for explanation
bit_len := bits.len_32(max)
if bit_len == 32 {
for {
value := rng.u32()
if value < max {
return value
}
}
} else {
mask := (u32(1) << (bit_len + 1)) - 1
for {
value := rng.u32() & mask
if value < max {
return value
}
}
}
return u32(0)
}
// rng.u64n(max) - return a 64bit u64 in [0, max)
[inline]
pub fn (mut rng MT19937RNG) u64n(max u64) u64 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
bit_len := bits.len_64(max)
if bit_len == 64 {
for {
value := rng.u64()
if value < max {
return value
}
}
} else {
mask := (u64(1) << (bit_len + 1)) - 1
for {
value := rng.u64() & mask
if value < max {
return value
}
}
}
return u64(0)
}
// rng.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng MT19937RNG) u32_in_range(min, max u32) u32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u32n(max - min)
}
// rng.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng MT19937RNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u64n(max - min)
}
// rng.intn(max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng MT19937RNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(rng.u32n(max))
}
// rng.i64n(max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng MT19937RNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(rng.u64n(max))
}
// rng.int_in_range(min, max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng MT19937RNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.intn(max - min)
}
// rng.i64_in_range(min, max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng MT19937RNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.i64n(max - min)
}
// rng.f32() - return a 32bit real in [0, 1)
[inline]
pub fn (mut rng MT19937RNG) f32() f32 {
return f32(rng.f64())
}
// rng.f64() - return 64bit real in [0, 1)
[inline]
pub fn (mut rng MT19937RNG) f64() f64 {
return f64(rng.u64() >> 11) * inv_f64_limit
}
// rng.f32n(max) - return 64bit real in [0, max)
[inline]
pub fn (mut rng MT19937RNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f32() * max
}
// rng.f64n(max) - return 64bit real in [0, max)
[inline]
pub fn (mut rng MT19937RNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f64() * max
}
// rng.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (mut rng MT19937RNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f32n(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng MT19937RNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f64n(max - min)
}

340
vlib/rand/mt19937_test.v Normal file
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@ -0,0 +1,340 @@
import rand
import math
const (
range_limit = 40
value_count = 1000
seeds = [[u32(0xcafebabe), u32(0xdeadbeef)], [u32(0xc0de), u32(0xfeed)]]
)
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn mt19937_basic_test() {
rng := rand.MT19937RNG{}
rng.seed([u32(0xdeadbeef)])
target := [956529277, 3842322136, 3319553134, 1843186657, 2704993644, 595827513, 938518626,
1676224337, 3221315650, 1819026461]
for i := 0; i < 10; i++ {
assert target[i] == rng.u32()
}
}
fn gen_randoms(seed_data []u32, bound int) []u64 {
bound_u64 := u64(bound)
mut randoms := [u64(0)].repeat(20)
mut rnd := rand.MT19937RNG{}
rnd.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rnd.u64n(bound_u64)
}
return randoms
}
fn test_mt19937_reproducibility() {
seed_data := rand.time_seed_array(2)
randoms1 := gen_randoms(seed_data, 1000)
randoms2 := gen_randoms(seed_data, 1000)
assert randoms1.len == randoms2.len
len := randoms1.len
for i in 0 .. len {
assert randoms1[i] == randoms2[i]
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_mt19937_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.MT19937RNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_mt19937_uniformity_u64() {
ranges := [14019545, 80240, 130]
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.MT19937RNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_mt19937_uniformity_f64() {
// The f64 version
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
check_uniformity_f64(rng)
}
}
fn test_mt19937_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_mt19937_u64n() {
max := u64(379091181005)
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_mt19937_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_mt19937_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_mt19937_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_mt19937_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_mt19937_intn() {
max := 2525642
for seed in seeds {
rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_mt19937_i64n() {
max := i64(3246727724653636)
for seed in seeds {
rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_mt19937_int_in_range() {
min := -4252
max := 1034
for seed in seeds {
rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_mt19937_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_mt19937_f32() {
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_mt19937_f64() {
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_mt19937_f32n() {
max := f32(357.0)
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32n(max)
assert value >= 0.0
assert value < max
}
}
}
fn test_mt19937_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64n(max)
assert value >= 0.0
assert value < max
}
}
}
fn test_mt19937_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_mt19937_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := rand.MT19937RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64_in_range(min, max)
assert value >= min
assert value < max
}
}
}

236
vlib/rand/musl_rng.v Normal file
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@ -0,0 +1,236 @@
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
import math.bits
// Ported from https://git.musl-libc.org/cgit/musl/tree/src/prng/rand_r.c
pub struct MuslRNG {
mut:
state u32 = time_seed_32()
}
pub fn (mut rng MuslRNG) seed(seed_data []u32) {
if seed_data.len != 1 {
eprintln('MuslRNG needs only one unsigned 32 bit integer as a seed.')
exit(1)
}
rng.state = seed_data[0]
}
[inline]
fn temper(prev u32) u32 {
mut x := prev
x ^= x >> 11
x ^= (x << 7) & 0x9D2C5680
x ^= (x << 15) & 0xEFC60000
x ^= (x >> 18)
return x
}
// rng.u32() - return a pseudorandom 32 bit unsigned u32
[inline]
pub fn (mut rng MuslRNG) u32() u32 {
rng.state = rng.state * 1103515245 + 12345
// We are not dividing by 2 (or shifting right by 1)
// because we want all 32-bits of random data
return temper(rng.state)
}
// rng.u64() - return a pseudorandom 64 bit unsigned u64
[inline]
pub fn (mut rng MuslRNG) u64() u64 {
return u64(rng.u32()) | (u64(rng.u32()) << 32)
}
// rn.u32n(max) - return a pseudorandom 32 bit unsigned u32 in [0, max)
[inline]
pub fn (mut rng MuslRNG) u32n(max u32) u32 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
// Check SysRNG in system_rng.c.v for explanation
bit_len := bits.len_32(max)
if bit_len == 32 {
for {
value := rng.u32()
if value < max {
return value
}
}
} else {
mask := (u32(1) << (bit_len + 1)) - 1
for {
value := rng.u32() & mask
if value < max {
return value
}
}
}
return u32(0)
}
// rn.u64n(max) - return a pseudorandom 64 bit unsigned u64 in [0, max)
[inline]
pub fn (mut rng MuslRNG) u64n(max u64) u64 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
bit_len := bits.len_64(max)
if bit_len == 64 {
for {
value := rng.u64()
if value < max {
return value
}
}
} else {
mask := (u64(1) << (bit_len + 1)) - 1
for {
value := rng.u64() & mask
if value < max {
return value
}
}
}
return u64(0)
}
// rn.u32_in_range(min, max) - return a pseudorandom 32 bit unsigned u32 in [min, max)
[inline]
pub fn (mut rng MuslRNG) u32_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u32n(max - min)
}
// rn.u64_in_range(min, max) - return a pseudorandom 64 bit unsigned u64 in [min, max)
[inline]
pub fn (mut rng MuslRNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u64n(max - min)
}
// rng.int() - return a 32-bit signed (possibly negative) int
[inline]
pub fn (mut rng MuslRNG) int() int {
return int(rng.u32())
}
// rng.i64() - return a 64-bit signed (possibly negative) i64
[inline]
pub fn (mut rng MuslRNG) i64() i64 {
return i64(rng.u64())
}
// rng.int31() - return a 31bit positive pseudorandom integer
[inline]
pub fn (mut rng MuslRNG) int31() int {
return int(rng.u32() >> 1)
}
// rng.int63() - return a 63bit positive pseudorandom integer
[inline]
pub fn (mut rng MuslRNG) int63() i64 {
return i64(rng.u64() >> 1)
}
// rng.intn(max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng MuslRNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(rng.u32n(max))
}
// rng.i64n(max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng MuslRNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(rng.u64n(max))
}
// rng.int_in_range(min, max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng MuslRNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.intn(max - min)
}
// rng.i64_in_range(min, max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng MuslRNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.i64n(max - min)
}
// rng.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng MuslRNG) f32() f32 {
return f32(rng.u32()) / max_u32_as_f32
}
// rng.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng MuslRNG) f64() f64 {
return f64(rng.u64()) / max_u64_as_f64
}
// rng.f32n() returns a pseudorandom f32 value in [0, max)
[inline]
pub fn (mut rng MuslRNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f32() * max
}
// rng.f64n() returns a pseudorandom f64 value in [0, max)
[inline]
pub fn (mut rng MuslRNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f64() * max
}
// rng.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (mut rng MuslRNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f32n(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng MuslRNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f64n(max - min)
}

330
vlib/rand/musl_rng_test.v Normal file
View File

@ -0,0 +1,330 @@
import rand
import math
const (
range_limit = 40
value_count = 1000
seeds = [[u32(42)], [u32(256)]]
)
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn gen_randoms(seed_data []u32, bound int) []u64 {
bound_u64 := u64(bound)
mut randoms := [u64(0)].repeat(20)
mut rnd := rand.MuslRNG{}
rnd.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rnd.u64n(bound_u64)
}
return randoms
}
fn test_musl_reproducibility() {
seed_data := rand.time_seed_array(1)
randoms1 := gen_randoms(seed_data, 1000)
randoms2 := gen_randoms(seed_data, 1000)
assert randoms1.len == randoms2.len
len := randoms1.len
for i in 0 .. len {
assert randoms1[i] == randoms2[i]
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_musl_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.MuslRNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_musl_uniformity_u64() {
ranges := [14019545, 80240, 130]
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.MuslRNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_musl_uniformity_f64() {
// The f64 version
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
check_uniformity_f64(rng)
}
}
fn test_musl_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_musl_u64n() {
max := u64(379091181005)
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_musl_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_musl_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_musl_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_musl_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_musl_intn() {
max := 2525642
for seed in seeds {
rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_musl_i64n() {
max := i64(3246727724653636)
for seed in seeds {
rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_musl_int_in_range() {
min := -4252
max := 1034
for seed in seeds {
rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_musl_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_musl_f32() {
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_musl_f64() {
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_musl_f32n() {
max := f32(357.0)
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < max
}
}
}
fn test_musl_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < max
}
}
}
fn test_musl_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= min
assert value < max
}
}
}
fn test_musl_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := rand.MuslRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= min
assert value < max
}
}
}

260
vlib/rand/pcg32.v
View File

@ -1,68 +1,234 @@
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
// Ported from http://www.pcg-random.org/download.html
// and https://github.com/imneme/pcg-c-basic/blob/master/pcg_basic.c
pub struct Pcg32 {
// Ported from http://www.pcg-random.org/download.html,
// https://github.com/imneme/pcg-c-basic/blob/master/pcg_basic.c, and
// https://github.com/imneme/pcg-c-basic/blob/master/pcg_basic.h
pub struct PCG32RNG {
mut:
state u64
inc u64
state u64 = u64(0x853c49e6748fea9b) ^ time_seed_64()
inc u64 = u64(0xda3e39cb94b95bdb) ^ time_seed_64()
}
/**
* new_pcg32 - a Pcg32 PRNG generator
* @param initstate - the initial state of the PRNG.
* @param initseq - the stream/step of the PRNG.
* @return a new Pcg32 PRNG instance
*/
pub fn new_pcg32(initstate u64, initseq u64) Pcg32 {
mut rng := Pcg32{
}
rng.state = u64(0)
rng.inc = (initseq<<u64(1)) | u64(1)
rng.next()
rng.state += initstate
rng.next()
// TODO: Remove in Phase 2 of reorganizing Random
pub fn new_pcg32(init_state, init_seq u64) PCG32RNG {
rng := PCG32RNG{}
rng.seed([u32(init_state), u32(init_state >> 32), u32(init_seq), u32(init_seq >> 32)])
return rng
}
/**
* Pcg32.next - update the PRNG state and get back the next random number
* @return the generated pseudo random number
*/
[inline]
pub fn (mut rng Pcg32) next() u32 {
oldstate := rng.state
rng.state = oldstate * (6364136223846793005) + rng.inc
xorshifted := u32(((oldstate>>u64(18)) ^ oldstate)>>u64(27))
rot := u32(oldstate>>u64(59))
return ((xorshifted>>rot) | (xorshifted<<((-rot) & u32(31))))
pub fn (mut rng PCG32RNG) bounded_next(bound u32) u32 {
return rng.u32n(bound)
}
/**
* Pcg32.bounded_next - update the PRNG state. Get the next number < bound
* @param bound - the returned random number will be < bound
* @return the generated pseudo random number
*/
// rng.seed(seed_data) - seed the PCG32RNG with 4 u32 values.
// The first 2 represent the 64-bit initial state as [lower 32 bits, higher 32 bits]
// The last 2 represent the 64-bit stream/step of the PRNG.
pub fn (mut rng PCG32RNG) seed(seed_data []u32) {
if seed_data.len != 4 {
eprintln('PCG32RNG needs 4 u32s to be seeded. First two the initial state and the last two the stream/step. Both in little endian format: [lower, higher]')
exit(1)
}
init_state := u64(seed_data[0]) | (u64(seed_data[1]) << 32)
init_seq := u64(seed_data[2]) | (u64(seed_data[3]) << 32)
rng.state = u64(0)
rng.inc = (init_seq << u64(1)) | u64(1)
rng.u32()
rng.state += init_state
rng.u32()
}
// rng.u32() - return a pseudorandom 32 bit unsigned u32
[inline]
pub fn (mut rng Pcg32) bounded_next(bound u32) u32 {
pub fn (mut rng PCG32RNG) u32() u32 {
oldstate := rng.state
rng.state = oldstate * (6364136223846793005) + rng.inc
xorshifted := u32(((oldstate >> u64(18)) ^ oldstate) >> u64(27))
rot := u32(oldstate >> u64(59))
return ((xorshifted >> rot) | (xorshifted << ((-rot) & u32(31))))
}
// rng.u64() - return a pseudorandom 64 bit unsigned u64
[inline]
pub fn (mut rng PCG32RNG) u64() u64 {
return u64(rng.u32()) | (u64(rng.u32()) << 32)
}
// rn.u32n(max) - return a pseudorandom 32 bit unsigned u32 in [0, max)
[inline]
pub fn (mut rng PCG32RNG) u32n(max u32) u32 {
if max == 0 {
eprintln('max must be positive')
exit(1)
}
// To avoid bias, we need to make the range of the RNG a multiple of
// bound, which we do by dropping output less than a threshold.
threshold := (-bound % bound)
// max, which we do by dropping output less than a threshold.
threshold := (-max % max)
// Uniformity guarantees that loop below will terminate. In practice, it
// should usually terminate quickly; on average (assuming all bounds are
// should usually terminate quickly; on average (assuming all max's are
// equally likely), 82.25% of the time, we can expect it to require just
// one iteration. In practice, bounds are typically small and only a
// one iteration. In practice, max's are typically small and only a
// tiny amount of the range is eliminated.
for {
r := rng.next()
r := rng.u32()
if r >= threshold {
return (r % bound)
return (r % max)
}
}
return u32(0)
}
// rn.u64n(max) - return a pseudorandom 64 bit unsigned u64 in [0, max)
[inline]
pub fn (mut rng PCG32RNG) u64n(max u64) u64 {
if max == 0 {
eprintln('max must be positive')
exit(1)
}
threshold := (-max % max)
for {
r := rng.u64()
if r >= threshold {
return (r % max)
}
}
return u64(0)
}
// rn.u32_in_range(min, max) - return a pseudorandom 32 bit unsigned u32 in [min, max)
[inline]
pub fn (mut rng PCG32RNG) u32_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u32n(max - min)
}
// rn.u64_in_range(min, max) - return a pseudorandom 64 bit unsigned u64 in [min, max)
[inline]
pub fn (mut rng PCG32RNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u64n(max - min)
}
// rng.int() - return a 32-bit signed (possibly negative) int
[inline]
pub fn (mut rng PCG32RNG) int() int {
return int(rng.u32())
}
// rng.i64() - return a 64-bit signed (possibly negative) i64
[inline]
pub fn (mut rng PCG32RNG) i64() i64 {
return i64(rng.u64())
}
// rng.int31() - return a 31bit positive pseudorandom integer
[inline]
pub fn (mut rng PCG32RNG) int31() int {
return int(rng.u32() >> 1)
}
// rng.int63() - return a 63bit positive pseudorandom integer
[inline]
pub fn (mut rng PCG32RNG) int63() i64 {
return i64(rng.u64() >> 1)
}
// rng.intn(max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng PCG32RNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(rng.u32n(max))
}
// rng.i64n(max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng PCG32RNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(rng.u64n(max))
}
// rng.int_in_range(min, max) - return a 32bit positive int in [0, max)
[inline]
pub fn (mut rng PCG32RNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.intn(max - min)
}
// rng.i64_in_range(min, max) - return a 64bit positive i64 in [0, max)
[inline]
pub fn (mut rng PCG32RNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min.')
exit(1)
}
return min + rng.i64n(max - min)
}
// rng.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng PCG32RNG) f32() f32 {
return f32(rng.u32()) / max_u32_as_f32
}
// rng.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng PCG32RNG) f64() f64 {
return f64(rng.u64()) / max_u64_as_f64
}
// rng.f32n() returns a pseudorandom f32 value in [0, max)
[inline]
pub fn (mut rng PCG32RNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f32() * max
}
// rng.f64n() returns a pseudorandom f64 value in [0, max)
[inline]
pub fn (mut rng PCG32RNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f64() * max
}
// rng.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (mut rng PCG32RNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f32n(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng PCG32RNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f64n(max - min)
}

340
vlib/rand/pcg32_test.v
View File

@ -1,36 +1,328 @@
import rand
import time
import math
fn show_u32s(a []u32){
mut res := []string{}
for x in a {
res << x.str()
}
print('[')
print(res.join(', '))
println(']')
}
fn gen_randoms(initstate i64, initseq i64, bound int) []u32 {
mut randoms := [u32(0)].repeat(20)
mut rnd := rand.new_pcg32( u64(initstate), u64(initseq) )
for i in 0..20 {
randoms[i] = rnd.bounded_next(u32(bound))
const (
range_limit = 40
value_count = 1000
seeds = [[u32(42), 242, 267, 14195], [u32(256), 340, 1451, 1505]]
)
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn gen_randoms(seed_data []u32, bound int) []u32 {
mut randoms := []u32{len: 20}
mut rng := rand.PCG32RNG{}
rng.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rng.u32n(u32(bound))
}
return randoms
}
fn test_pcg32_reproducibility() {
t := time.ticks()
tseq := t % 23237671
println('t: $t | tseq: $tseq')
randoms1 := gen_randoms(t, tseq, 1000)
randoms2 := gen_randoms(t, tseq, 1000)
randoms1 := gen_randoms(rand.time_seed_array(4), 1000)
randoms2 := gen_randoms(rand.time_seed_array(4), 1000)
assert randoms1.len == randoms2.len
show_u32s(randoms1)
show_u32s(randoms2)
len := randoms1.len
for i in 0..len {
for i in 0 .. len {
assert randoms1[i] == randoms2[i]
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_pcg32_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.PCG32RNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_pcg32_uniformity_u64() {
ranges := [14019545, 80240, 130]
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.PCG32RNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_pcg32_uniformity_f64() {
// The f64 version
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
check_uniformity_f64(rng)
}
}
fn test_pcg32_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_pcg32_u64n() {
max := u64(379091181005)
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_pcg32_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_pcg32_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_pcg32_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_pcg32_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_pcg32_intn() {
max := 2525642
for seed in seeds {
rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_pcg32_i64n() {
max := i64(3246727724653636)
for seed in seeds {
rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_pcg32_int_in_range() {
min := -4252
max := 1034
for seed in seeds {
rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_pcg32_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_pcg32_f32() {
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_pcg32_f64() {
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_pcg32_f32n() {
max := f32(357.0)
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < max
}
}
}
fn test_pcg32_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < max
}
}
}
fn test_pcg32_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= min
assert value < max
}
}
}
fn test_pcg32_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := rand.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= min
assert value < max
}
}
}

133
vlib/rand/rand.v
View File

@ -3,8 +3,12 @@
// that can be found in the LICENSE file.
module rand
fn C.rand() int
// TODO: Remove these functions once done:
// 1. C.rand()
// 2. seed()
// 3. next()
// 4. rand_r()
// fn C.rand() int
pub fn seed(s int) {
C.srand(s)
}
@ -23,32 +27,155 @@ pub fn rand_r(seed &int) int {
return ns & 0x7fffffff
}
const (
default_rng = new_default({})
)
pub struct PRNGConfigStruct {
seed []u32 = time_seed_array(2)
}
pub fn new_default(config PRNGConfigStruct) &WyRandRNG {
rng := &WyRandRNG{}
rng.seed(config.seed)
return rng
}
// u32() - returns a uniformly distributed pseudorandom 32-bit unsigned u32
pub fn u32() u32 {
return default_rng.u32()
}
// u64() - returns a uniformly distributed pseudorandom 64-bit unsigned u64
pub fn u64() u64 {
return default_rng.u64()
}
// u32n(max) - returns a uniformly distributed pseudorandom 32-bit unsigned u32 in [0, max)
pub fn u32n(max u32) u32 {
return default_rng.u32n(max)
}
// u64n(max) - returns a uniformly distributed pseudorandom 64-bit unsigned u64 in [0, max)
pub fn u64n(max u64) u64 {
return default_rng.u64n(max)
}
// u32n() - returns a uniformly distributed pseudorandom 32-bit unsigned u32 in [min, max)
pub fn u32_in_range(min, max u32) u32 {
return default_rng.u32_in_range(min, max)
}
// u64_in_range(min, max) - returns a uniformly distributed pseudorandom 64-bit unsigned u64 in [min, max)
pub fn u64_in_range(min, max u64) u64 {
return default_rng.u64_in_range(min, max)
}
// int() - returns a uniformly distributed pseudorandom 32-bit signed (possibly negative) int
pub fn int() int {
return default_rng.int()
}
// intn(max) - returns a uniformly distributed pseudorandom 32-bit signed positive int in [0, max)
pub fn intn(max int) int {
return default_rng.intn(max)
}
// int_in_range(min, max) - returns a uniformly distributed pseudorandom
// 32-bit signed int in [min, max)
pub fn int_in_range(min, max int) int {
return default_rng.int_in_range(min, max)
}
// int31() - returns a uniformly distributed pseudorandom 31-bit signed positive int
pub fn int31() int {
return default_rng.int31()
}
// i64() - returns a uniformly distributed pseudorandom 64-bit signed (possibly negative) i64
pub fn i64() i64 {
return default_rng.i64()
}
// i64n(max) - returns a uniformly distributed pseudorandom 64-bit signed positive i64 in [0, max)
pub fn i64n(max i64) i64 {
return default_rng.i64n(max)
}
// i64_in_range(min, max) - returns a uniformly distributed pseudorandom
// 64-bit signed int in [min, max)
pub fn i64_in_range(min, max i64) i64 {
return default_rng.i64_in_range(min, max)
}
// int63() - returns a uniformly distributed pseudorandom 63-bit signed positive int
pub fn int63() i64 {
return default_rng.int63()
}
// f32() - returns a uniformly distributed 32-bit floating point in [0, 1)
pub fn f32() f32 {
return default_rng.f32()
}
// f64() - returns a uniformly distributed 64-bit floating point in [0, 1)
pub fn f64() f64 {
return default_rng.f64()
}
// f32n() - returns a uniformly distributed 32-bit floating point in [0, max)
pub fn f32n(max f32) f32 {
return default_rng.f32n(max)
}
// f64n() - returns a uniformly distributed 64-bit floating point in [0, max)
pub fn f64n(max f64) f64 {
return default_rng.f64n(max)
}
// f32_in_range(min, max) - returns a uniformly distributed 32-bit floating point in [min, max)
pub fn f32_in_range(min, max f32) f32 {
return default_rng.f32_in_range(min, max)
}
// f64_in_range(min, max) - returns a uniformly distributed 64-bit floating point in [min, max)
pub fn f64_in_range(min, max f64) f64 {
return default_rng.f64_in_range(min, max)
}
// rand_f32 return a random f32 between 0 and max
[deprecated]
pub fn rand_f32(max f32) f32 {
return rand_uniform_f32() * max
}
// rand_f32 return a random f32 in range min and max
[deprecated]
pub fn rand_f32_in_range(min, max f32) f32 {
return min + rand_uniform_f32() * (max - min)
}
// rand_f64 return a random f64 between 0 (inclusive) and max (exclusive)
[deprecated]
pub fn rand_f64(max f64) f64 {
return rand_uniform_f64() * max
}
// rand_f64 return a random f64 in range min (inclusive) and max (exclusive)
[deprecated]
pub fn rand_f64_in_range(min, max f64) f64 {
return min + rand_uniform_f64() * (max - min)
}
// rand_uniform_f32 returns a uniformly distributed f32 in the range 0 (inclusive) and 1 (exclusive)
[deprecated]
pub fn rand_uniform_f32() f32 {
return f32(C.rand()) / f32(C.RAND_MAX)
}
// rand_uniform_f64 returns a uniformly distributed f64 in the range 0 (inclusive) and 1 (exclusive)
[deprecated]
pub fn rand_uniform_f64() f64 {
return f64(C.rand()) / f64(C.RAND_MAX)
}
}

151
vlib/rand/random_numbers_test.v
View File

@ -1,4 +1,5 @@
import rand
import math
const (
rnd_count = 40
@ -53,7 +54,7 @@ fn assert_randoms_equal(r1, r2 []int) {
}
}
fn test_rand_f32() {
fn test_rand_f32_old() {
for seed in seeds {
rand.seed(seed)
for _ in 0 .. rnd_count {
@ -64,7 +65,7 @@ fn test_rand_f32() {
}
}
fn test_rand_f32_in_range() {
fn test_rand_f32_in_range_old() {
for seed in seeds {
rand.seed(seed)
for _ in 0 .. rnd_count {
@ -75,7 +76,7 @@ fn test_rand_f32_in_range() {
}
}
fn test_rand_f64() {
fn test_rand_f64_old() {
for seed in seeds {
rand.seed(seed)
for _ in 0 .. rnd_count {
@ -86,7 +87,7 @@ fn test_rand_f64() {
}
}
fn test_rand_f64_in_range() {
fn test_rand_f64_in_range_old() {
for seed in seeds {
rand.seed(seed)
for _ in 0 .. rnd_count {
@ -118,3 +119,145 @@ fn test_rand_uniform_f64() {
}
}
}
fn test_rand_u32n() {
max := u32(4287502)
for _ in 0 .. rnd_count {
assert rand.u32n(max) < max
}
}
fn test_rand_u64n() {
max := u64(23442353534587502)
for _ in 0 .. rnd_count {
assert rand.u64n(max) < max
}
}
fn test_rand_u32_in_range() {
min := u32(5256)
max := u32(4287502)
for _ in 0 .. rnd_count {
value := rand.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
fn test_rand_u64_in_range() {
min := u64(4265266246)
max := u64(23442353534587502)
for _ in 0 .. rnd_count {
value := rand.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
fn test_rand_intn() {
max := 720948723
for _ in 0 .. rnd_count {
value := rand.intn(max)
assert value >= 0
assert value < max
}
}
fn test_rand_i64n() {
max := i64(209487239094)
for _ in 0 .. rnd_count {
value := rand.i64n(max)
assert value >= 0
assert value < max
}
}
fn test_rand_int_in_range() {
min := -34058
max := -10542
for _ in 0 .. rnd_count {
value := rand.int_in_range(min, max)
assert value >= min
assert value < max
}
}
fn test_rand_i64_in_range() {
min := i64(-5026245)
max := i64(209487239094)
for _ in 0 .. rnd_count {
value := rand.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
fn test_rand_int31() {
for _ in 0 .. rnd_count {
value := rand.int31()
assert value >= 0
assert value <= math.max_i32
}
}
fn test_rand_int63() {
for _ in 0 .. rnd_count {
value := rand.int63()
assert value >= 0
assert value <= math.max_i64
}
}
fn test_rand_f32() {
for _ in 0 .. rnd_count {
value := rand.f32()
assert value >= 0.0
assert value < 1.0
}
}
fn test_rand_f64() {
for _ in 0 .. rnd_count {
value := rand.f64()
assert value >= 0.0
assert value < 1.0
}
}
fn test_rand_f32n() {
max := f32(34.52)
for _ in 0 .. rnd_count {
value := rand.f32n(max)
assert value >= 0.0
assert value < max
}
}
fn test_rand_f64n() {
max := 3495.2
for _ in 0 .. rnd_count {
value := rand.f64n(max)
assert value >= 0.0
assert value < max
}
}
fn test_rand_f32_in_range() {
min := f32(-10.4)
max := f32(43.2)
for _ in 0 .. rnd_count {
value := rand.f32_in_range(min, max)
assert value >= min
assert value < max
}
}
fn test_rand_f64_in_range() {
min := -10980.4
max := -2.0
for _ in 0 .. rnd_count {
value := rand.f64_in_range(min, max)
assert value >= min
assert value < max
}
}

232
vlib/rand/splitmix64.v
View File

@ -1,52 +1,222 @@
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
// Ported from http://xoshiro.di.unimi.it/splitmix64.c
struct Splitmix64 {
pub struct SplitMix64RNG {
mut:
state u64
state u64 = time_seed_64()
has_extra bool = false
extra u32
}
/**
* new_splitmix64 - a Splitmix64 PRNG generator
* @param seed the initial seed of the PRNG.
* @return a new Splitmix64 PRNG instance
*/
pub fn new_splitmix64(seed u64) Splitmix64 {
return Splitmix64{
seed}
// rng.seed(seed_data) sets the seed of the accepting SplitMix64RNG to the given data
// in little-endian format (i.e. lower 32 bits are in [0] and higher 32 bits in [1]).
pub fn (mut rng SplitMix64RNG) seed(seed_data []u32) {
if seed_data.len != 2 {
eprintln('SplitMix64RNG needs 2 32-bit unsigned integers as the seed.')
exit(1)
}
rng.state = seed_data[0] | (u64(seed_data[1]) << 32)
rng.has_extra = false
}
/**
* Splitmix64.next - update the PRNG state and get back the next random number
* @return the generated pseudo random number
*/
// rng.u32() updates the PRNG state and returns the next pseudorandom u32
[inline]
pub fn (mut rng Splitmix64) next() u64 {
pub fn (mut rng SplitMix64RNG) u32() u32 {
if rng.has_extra {
rng.has_extra = false
return rng.extra
}
full_value := rng.u64()
lower := u32(full_value & lower_mask)
upper := u32(full_value >> 32)
rng.extra = upper
rng.has_extra = true
return lower
}
// rng.u64() updates the PRNG state and returns the next pseudorandom u64
[inline]
pub fn (mut rng SplitMix64RNG) u64() u64 {
rng.state += (0x9e3779b97f4a7c15)
mut z := rng.state
z = (z ^ ((z>>u64(30)))) * (0xbf58476d1ce4e5b9)
z = (z ^ ((z>>u64(27)))) * (0x94d049bb133111eb)
return z ^ (z>>(31))
z = (z ^ ((z >> u64(30)))) * (0xbf58476d1ce4e5b9)
z = (z ^ ((z >> u64(27)))) * (0x94d049bb133111eb)
return z ^ (z >> (31))
}
/**
* Splitmix64.bounded_next - Get the next random number < bound
* @param bound - the returned random number will be < bound
* @return the generated pseudo random number
*/
// rng.u32n(bound) returns a pseudorandom u32 less than the bound
[inline]
pub fn (mut rng Splitmix64) bounded_next(bound u64) u64 {
pub fn (mut rng SplitMix64RNG) u32n(bound u32) u32 {
// This function is kept similar to the u64 version
if bound == 0 {
eprintln('max must be non-zero')
exit(1)
}
threshold := -bound % bound
for {
r := rng.next()
r := rng.u32()
if r >= threshold {
return r % bound
}
}
return u32(0)
}
// rng.u64n(bound) returns a pseudorandom u64 less than the bound
[inline]
pub fn (mut rng SplitMix64RNG) u64n(bound u64) u64 {
// See pcg32.v for explanation of comment. This algorithm
// existed before the refactoring.
if bound == 0 {
eprintln('max must be non-zero')
exit(1)
}
threshold := -bound % bound
for {
r := rng.u64()
if r >= threshold {
return r % bound
}
}
return u64(0)
}
// rng.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) u32_in_range(min, max u32) u32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u32n(max - min)
}
// rng.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u64n(max - min)
}
// rng.int() returns a pseudorandom 32-bit int (which may be negative)
[inline]
pub fn (mut rng SplitMix64RNG) int() int {
return int(rng.u32())
}
// rng.i64() returns a pseudorandom 64-bit i64 (which may be negative)
[inline]
pub fn (mut rng SplitMix64RNG) i64() i64 {
return i64(rng.u64())
}
// rng.int31() returns a pseudorandom 31-bit int which is non-negative
[inline]
pub fn (mut rng SplitMix64RNG) int31() int {
return int(rng.u32() & u31_mask) // Set the 32nd bit to 0.
}
// rng.int63() returns a pseudorandom 63-bit int which is non-negative
[inline]
pub fn (mut rng SplitMix64RNG) int63() i64 {
return i64(rng.u64() & u63_mask) // Set the 64th bit to 0.
}
// rng.intn(max) returns a pseudorandom int that lies in [0, max)
[inline]
pub fn (mut rng SplitMix64RNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(rng.u32n(max))
}
// rng.i64n(max) returns a pseudorandom int that lies in [0, max)
[inline]
pub fn (mut rng SplitMix64RNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(rng.u64n(max))
}
// rng.int_in_range(min, max) returns a pseudorandom int that lies in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
// This supports negative ranges like [-10, -5) because the difference is positive
return min + rng.intn(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.i64n(max - min)
}
// rng.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng SplitMix64RNG) f32() f32 {
return f32(rng.u32()) / max_u32_as_f32
}
// rng.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng SplitMix64RNG) f64() f64 {
return f64(rng.u64()) / max_u64_as_f64
}
// rng.f32n() returns a pseudorandom f32 value in [0, max)
[inline]
pub fn (mut rng SplitMix64RNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f32() * max
}
// rng.f64n() returns a pseudorandom f64 value in [0, max)
[inline]
pub fn (mut rng SplitMix64RNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f64() * max
}
// rng.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f32n(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng SplitMix64RNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f64n(max - min)
}

338
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@ -1,36 +1,330 @@
import rand
import time
import math
fn show_u64s(a []u64){
mut res := []string{}
for x in a {
res << x.str()
}
print('[')
print(res.join(', '))
println(']')
}
const (
range_limit = 40
value_count = 1000
seeds = [[u32(42), 0], [u32(256), 0]]
)
fn gen_randoms(seed i64, bound int) []u64 {
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn gen_randoms(seed_data []u32, bound int) []u64 {
bound_u64 := u64(bound)
mut randoms := [u64(0)].repeat(20)
mut rnd := rand.new_splitmix64( u64(seed) )
for i in 0..20 {
randoms[i] = rnd.bounded_next(u64(bound))
mut rnd := rand.SplitMix64RNG{}
rnd.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rnd.u64n(bound_u64)
}
return randoms
}
fn test_splitmix64_reproducibility() {
t := time.ticks()
println('t: $t')
randoms1 := gen_randoms(t, 1000)
randoms2 := gen_randoms(t, 1000)
seed_data := rand.time_seed_array(2)
randoms1 := gen_randoms(seed_data, 1000)
randoms2 := gen_randoms(seed_data, 1000)
assert randoms1.len == randoms2.len
show_u64s( randoms1 )
show_u64s( randoms2 )
len := randoms1.len
for i in 0..len {
for i in 0 .. len {
assert randoms1[i] == randoms2[i]
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_splitmix64_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.SplitMix64RNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_splitmix64_uniformity_u64() {
ranges := [14019545, 80240, 130]
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.SplitMix64RNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_splitmix64_uniformity_f64() {
// The f64 version
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
check_uniformity_f64(rng)
}
}
fn test_splitmix64_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_splitmix64_u64n() {
max := u64(379091181005)
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_splitmix64_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_splitmix64_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_splitmix64_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_splitmix64_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_splimix64_intn() {
max := 2525642
for seed in seeds {
rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_splimix64_i64n() {
max := i64(3246727724653636)
for seed in seeds {
rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_splimix64_int_in_range() {
min := -4252
max := 230549862
for seed in seeds {
rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_splimix64_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_splitmix64_f32() {
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_splitmix64_f64() {
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_splitmix64_f32n() {
max := f32(357.0)
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < max
}
}
}
fn test_splitmix64_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < max
}
}
}
fn test_splitmix64_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= min
assert value < max
}
}
}
fn test_splitmix64_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= min
assert value < max
}
}
}

291
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// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
import math.bits
// Implementation note:
// ====================
// C.rand() is okay to use within its defined range of C.RAND_MAX.
// (See: https://web.archive.org/web/20180801210127/http://eternallyconfuzzled.com/arts/jsw_art_rand.aspx)
// The problem is, this value varies with the libc implementation. On windows,
// for example, RAND_MAX is usually a measly 32767, whereas on (newer) linux it's generaly
// 2147483647. The repetition period also varies wildly. In order to provide more entropy
// without altering the underlying algorithm too much, this implementation simply
// requests for more random bits until the necessary width for the integers is achieved.
const (
rand_limit = u64(C.RAND_MAX)
rand_bitsize = bits.len_64(rand_limit)
u32_iter_count = calculate_iterations_for(32)
u64_iter_count = calculate_iterations_for(64)
)
fn calculate_iterations_for(bits int) int {
base := bits / rand_bitsize
extra := if bits % rand_bitsize == 0 { 0 } else { 1 }
return base + extra
}
// Size constants to avoid importing the entire math module
const (
max_u32 = 0xFFFFFFFF
max_u64 = 0xFFFFFFFFFFFFFFFF
max_u32_as_f32 = f32(max_u32)
max_u64_as_f64 = f64(max_u64)
)
// Masks for fast modular division
const (
u31_mask = u32(0x7FFFFFFF)
u63_mask = u64(0x7FFFFFFFFFFFFFFF)
)
// C.rand returns a pseudorandom integer from 0 (inclusive) to C.RAND_MAX (exclusive)
fn C.rand() int
// C.srand seeds the internal PRNG with the given int seed.
// fn C.srand(seed int)
// SysRNG is the PRNG provided by default in the libc implementiation that V uses.
pub struct SysRNG {
mut:
seed u32 = time_seed_32()
}
// r.seed() sets the seed of the accepting SysRNG to the given data.
pub fn (mut r SysRNG) seed(seed_data []u32) {
if seed_data.len != 1 {
eprintln('SysRNG needs one 32-bit unsigned integer as the seed.')
exit(1)
}
r.seed = seed_data[0]
C.srand(int(r.seed))
}
// r.default_rand() exposes the default behavior of the system's RNG
// (equivalent to calling C.rand()). Recommended for testing/comparison
// b/w V and other languages using libc and not for regular use.
// This is also a one-off feature of SysRNG, similar to the global seed
// situation. Other generators will not have this.
[inline]
pub fn (r SysRNG) default_rand() int {
return C.rand()
}
// r.u32() returns a pseudorandom u32 value less than 2^32
[inline]
pub fn (r SysRNG) u32() u32 {
mut result := u32(C.rand())
for i in 1 .. u32_iter_count {
result = result ^ (u32(C.rand()) << (rand_bitsize * i))
}
return result
}
// r.u64() returns a pseudorandom u64 value less than 2^64
[inline]
pub fn (r SysRNG) u64() u64 {
mut result := u64(C.rand())
for i in 1 .. u64_iter_count {
result = result ^ (u64(C.rand()) << (rand_bitsize * i))
}
return result
}
// r.u32n(max) returns a pseudorandom u32 value that is guaranteed to be less than max
[inline]
pub fn (r SysRNG) u32n(max u32) u32 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
// Owing to the pigeon-hole principle, we can't simply do
// val := rng.u32() % max.
// It'll wreck the properties of the distribution unless
// max evenly divides 2^32. So we divide evenly to
// the closest power of two. Then we loop until we find
// an int in the required range
bit_len := bits.len_32(max)
if bit_len == 32 {
for {
value := r.u32()
if value < max {
return value
}
}
} else {
mask := (u32(1) << (bit_len + 1)) - 1
for {
value := r.u32() & mask
if value < max {
return value
}
}
}
return u32(0)
}
// r.u64n(max) returns a pseudorandom u64 value that is guaranteed to be less than max
[inline]
pub fn (r SysRNG) u64n(max u64) u64 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
// Similar procedure for u64s
bit_len := bits.len_64(max)
if bit_len == 64 {
for {
value := r.u64()
if value < max {
return value
}
}
} else {
mask := (u64(1) << (bit_len + 1)) - 1
for {
value := r.u64() & mask
if value < max {
return value
}
}
}
return u64(0)
}
// r.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
[inline]
pub fn (r SysRNG) u32_in_range(min, max u32) u32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + r.u32n(max - min)
}
// r.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
[inline]
pub fn (r SysRNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + r.u64n(max - min)
}
// r.int() returns a pseudorandom 32-bit int (which may be negative)
[inline]
pub fn (r SysRNG) int() int {
return int(r.u32())
}
// r.i64() returns a pseudorandom 64-bit i64 (which may be negative)
[inline]
pub fn (r SysRNG) i64() i64 {
return i64(r.u64())
}
// r.int31() returns a pseudorandom 31-bit int which is non-negative
[inline]
pub fn (r SysRNG) int31() int {
return int(r.u32() & u31_mask) // Set the 32nd bit to 0.
}
// r.int63() returns a pseudorandom 63-bit int which is non-negative
[inline]
pub fn (r SysRNG) int63() i64 {
return i64(r.u64() & u63_mask) // Set the 64th bit to 0.
}
// r.intn(max) returns a pseudorandom int that lies in [0, max)
[inline]
pub fn (r SysRNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(r.u32n(max))
}
// r.i64n(max) returns a pseudorandom i64 that lies in [0, max)
[inline]
pub fn (r SysRNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(r.u64n(max))
}
// r.int_in_range(min, max) returns a pseudorandom int that lies in [min, max)
[inline]
pub fn (r SysRNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
// This supports negative ranges like [-10, -5) because the difference is positive
return min + r.intn(max - min)
}
// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (r SysRNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + r.i64n(max - min)
}
// r.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (r SysRNG) f32() f32 {
return f32(r.u32()) / max_u32_as_f32
}
// r.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (r SysRNG) f64() f64 {
return f64(r.u64()) / max_u64_as_f64
}
// r.f32n() returns a pseudorandom f32 value in [0, max)
[inline]
pub fn (r SysRNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return r.f32() * max
}
// r.f64n() returns a pseudorandom f64 value in [0, max)
[inline]
pub fn (r SysRNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return r.f64() * max
}
// r.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (r SysRNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + r.f32n(max - min)
}
// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (r SysRNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + r.f64n(max - min)
}

15
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// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
// Until there's a portable, JS has a seeded way to produce random numbers
// and not just Math.random(), use any of the existing implementations
// as the System's RNG
type SysRNG WyRandRNG
// In the JS version, we simply return the same int as is normally generated.
[inline]
pub fn (r SysRNG) default_rand() int {
return r.int()
}

354
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import rand
import math
const (
range_limit = 40
value_count = 1000
seeds = [u32(42), 256]
)
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn get_n_randoms(n int, r rand.SysRNG) []int {
mut ints := []int{cap: n}
for _ in 0 .. n {
ints << r.int()
}
return ints
}
fn test_sys_rng_reproducibility() {
// Note that C.srand() sets the seed globally.
// So the order of seeding matters. It is recommended
// to obtain all necessary data first, then set the
// seed for another batch of data.
for seed in seeds {
seed_data := [seed]
r1 := rand.SysRNG{}
r2 := rand.SysRNG{}
r1.seed(seed_data)
ints1 := get_n_randoms(value_count, r1)
r2.seed(seed_data)
ints2 := get_n_randoms(value_count, r2)
assert ints1 == ints2
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_sys_rng_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.SysRNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_sys_rng_uniformity_u64() {
// This assumes that C.rand() produces uniform results to begin with.
// If the failure persists, report an issue on GitHub
ranges := [14019545, 80240, 130]
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.SysRNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_sys_rng_uniformity_f64() {
// The f64 version
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
check_uniformity_f64(rng)
}
}
fn test_sys_rng_u32n() {
max := 16384
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_sys_rng_u64n() {
max := u64(379091181005)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_sys_rng_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_sys_rng_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_sys_rng_intn() {
max := 2525642
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_sys_rng_i64n() {
max := i64(3246727724653636)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_sys_rng_int_in_range() {
min := -4252
max := 23054962
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_sys_rng_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_sys_rng_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_sys_rng_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_sys_rng_f32() {
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_sys_rng_f64() {
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_sys_rng_f32n() {
max := f32(357.0)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < max
}
}
}
fn test_sys_rng_f64n() {
max := 1.52e6
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < max
}
}
}
fn test_sys_rng_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= min
assert value < max
}
}
}
fn test_sys_rng_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
seed_data := [seed]
rng := rand.SysRNG{}
rng.seed(seed_data)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= min
assert value < max
}
}
}

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// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
import time
// Commonly used constants across RNGs
const (
lower_mask = u64(0x00000000ffffffff)
)
// Constants taken from Numerical Recipes
[inline]
fn nr_next(prev u32) u32 {
return prev * 1664525 + 1013904223
}
// utility function that return the required number of u32s generated from system time
[inline]
pub fn time_seed_array(count int) []u32 {
mut seed := u32(time.now().unix_time())
mut seed_data := []u32{cap: count}
for _ in 0 .. count {
seed = nr_next(seed)
seed_data << nr_next(seed)
}
return seed_data
}
[inline]
fn time_seed_32() u32 {
return time_seed_array(1)[0]
}
[inline]
fn time_seed_64() u64 {
seed_data := time_seed_array(2)
lower := u64(seed_data[0])
upper := u64(seed_data[1])
return lower | (upper << 32)
}

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// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module rand
import math.bits
import hash.wyhash
// Redefinition of some constants that we will need for pseudorandom number generation
const (
wyp0 = u64(0xa0761d6478bd642f)
wyp1 = u64(0xe7037ed1a0b428db)
)
// RNG based on the WyHash hashing algorithm
pub struct WyRandRNG {
mut:
state u64 = time_seed_64()
has_extra bool = false
extra u32
}
// seed() - Set the seed, needs only two u32s in little endian format as [lower, higher]
pub fn (mut rng WyRandRNG) seed(seed_data []u32) {
if seed_data.len != 2 {
eprintln('WyRandRNG needs 2 32-bit unsigned integers as the seed.')
exit(1)
}
rng.state = seed_data[0] | (u64(seed_data[1]) << 32)
rng.has_extra = false
}
// rng.u32() updates the PRNG state and returns the next pseudorandom u32
[inline]
pub fn (mut rng WyRandRNG) u32() u32 {
if rng.has_extra {
rng.has_extra = false
return rng.extra
}
full_value := rng.u64()
lower := u32(full_value & lower_mask)
upper := u32(full_value >> 32)
rng.extra = upper
rng.has_extra = true
return lower
}
// rng.u64() updates the PRNG state and returns the next pseudorandom u64
[inline]
pub fn (mut rng WyRandRNG) u64() u64 {
unsafe {
mut seed1 := rng.state
seed1 += wyp0
rng.state = seed1
return wyhash.wymum(seed1 ^ wyp1, seed1)
}
return 0
}
// rng.u32n(max) returns a pseudorandom u32 less than the max
[inline]
pub fn (mut rng WyRandRNG) u32n(max u32) u32 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
// Check SysRNG in system_rng.c.v for explanation
bit_len := bits.len_32(max)
if bit_len == 32 {
for {
value := rng.u32()
if value < max {
return value
}
}
} else {
mask := (u32(1) << (bit_len + 1)) - 1
for {
value := rng.u32() & mask
if value < max {
return value
}
}
}
return u32(0)
}
// rng.u64n(max) returns a pseudorandom u64 less than the max
[inline]
pub fn (mut rng WyRandRNG) u64n(max u64) u64 {
if max == 0 {
eprintln('max must be positive integer')
exit(1)
}
bit_len := bits.len_64(max)
if bit_len == 64 {
for {
value := rng.u64()
if value < max {
return value
}
}
} else {
mask := (u64(1) << (bit_len + 1)) - 1
for {
value := rng.u64() & mask
if value < max {
return value
}
}
}
return u64(0)
}
// rng.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng WyRandRNG) u32_in_range(min, max u32) u32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u32n(max - min)
}
// rng.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
[inline]
pub fn (mut rng WyRandRNG) u64_in_range(min, max u64) u64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.u64n(max - min)
}
// rng.int() returns a pseudorandom 32-bit int (which may be negative)
[inline]
pub fn (mut rng WyRandRNG) int() int {
return int(rng.u32())
}
// rng.i64() returns a pseudorandom 64-bit i64 (which may be negative)
[inline]
pub fn (mut rng WyRandRNG) i64() i64 {
return i64(rng.u64())
}
// rng.int31() returns a pseudorandom 31-bit int which is non-negative
[inline]
pub fn (mut rng WyRandRNG) int31() int {
return int(rng.u32() & u31_mask) // Set the 32nd bit to 0.
}
// rng.int63() returns a pseudorandom 63-bit int which is non-negative
[inline]
pub fn (mut rng WyRandRNG) int63() i64 {
return i64(rng.u64() & u63_mask) // Set the 64th bit to 0.
}
// rng.intn(max) returns a pseudorandom int that lies in [0, max)
[inline]
pub fn (mut rng WyRandRNG) intn(max int) int {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return int(rng.u32n(max))
}
// rng.i64n(max) returns a pseudorandom int that lies in [0, max)
[inline]
pub fn (mut rng WyRandRNG) i64n(max i64) i64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return i64(rng.u64n(max))
}
// rng.int_in_range(min, max) returns a pseudorandom int that lies in [min, max)
[inline]
pub fn (mut rng WyRandRNG) int_in_range(min, max int) int {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
// This supports negative ranges like [-10, -5) because the difference is positive
return min + rng.intn(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng WyRandRNG) i64_in_range(min, max i64) i64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.i64n(max - min)
}
// rng.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng WyRandRNG) f32() f32 {
return f32(rng.u32()) / max_u32_as_f32
}
// rng.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
[inline]
pub fn (mut rng WyRandRNG) f64() f64 {
return f64(rng.u64()) / max_u64_as_f64
}
// rng.f32n() returns a pseudorandom f32 value in [0, max)
[inline]
pub fn (mut rng WyRandRNG) f32n(max f32) f32 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f32() * max
}
// rng.f64n() returns a pseudorandom f64 value in [0, max)
[inline]
pub fn (mut rng WyRandRNG) f64n(max f64) f64 {
if max <= 0 {
eprintln('max has to be positive.')
exit(1)
}
return rng.f64() * max
}
// rng.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
[inline]
pub fn (mut rng WyRandRNG) f32_in_range(min, max f32) f32 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f32n(max - min)
}
// rng.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
[inline]
pub fn (mut rng WyRandRNG) f64_in_range(min, max f64) f64 {
if max <= min {
eprintln('max must be greater than min')
exit(1)
}
return min + rng.f64n(max - min)
}

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import rand
import math
const (
range_limit = 40
value_count = 1000
seeds = [[u32(42), 0], [u32(256), 0]]
)
const (
sample_size = 1000
stats_epsilon = 0.05
inv_sqrt_12 = 1.0 / math.sqrt(12)
)
fn gen_randoms(seed_data []u32, bound int) []u64 {
bound_u64 := u64(bound)
mut randoms := [u64(0)].repeat(20)
mut rnd := rand.WyRandRNG{}
rnd.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rnd.u64n(bound_u64)
}
return randoms
}
fn test_wyrand_reproducibility() {
seed_data := rand.time_seed_array(2)
randoms1 := gen_randoms(seed_data, 1000)
randoms2 := gen_randoms(seed_data, 1000)
assert randoms1.len == randoms2.len
len := randoms1.len
for i in 0 .. len {
assert randoms1[i] == randoms2[i]
}
}
// TODO: use the `in` syntax and remove this function
// after generics has been completely implemented
fn found(value u64, arr []u64) bool {
for item in arr {
if value == item {
return true
}
}
return false
}
fn test_wyrand_variability() {
// If this test fails and if it is certainly not the implementation
// at fault, try changing the seed values. Repeated values are
// improbable but not impossible.
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
mut values := []u64{cap: value_count}
for i in 0 .. value_count {
value := rng.u64()
assert !found(value, values)
assert values.len == i
values << value
}
}
}
fn check_uniformity_u64(rng rand.WyRandRNG, range u64) {
range_f64 := f64(range)
expected_mean := range_f64 / 2.0
mut variance := 0.0
for _ in 0 .. sample_size {
diff := f64(rng.u64n(range)) - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := range_f64 * inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_wyrand_uniformity_u64() {
ranges := [14019545, 80240, 130]
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(rng, range)
}
}
}
fn check_uniformity_f64(rng rand.WyRandRNG) {
expected_mean := 0.5
mut variance := 0.0
for _ in 0 .. sample_size {
diff := rng.f64() - expected_mean
variance += diff * diff
}
variance /= sample_size - 1
sigma := math.sqrt(variance)
expected_sigma := inv_sqrt_12
error := (sigma - expected_sigma) / expected_sigma
assert math.abs(error) < stats_epsilon
}
fn test_wyrand_uniformity_f64() {
// The f64 version
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
check_uniformity_f64(rng)
}
}
fn test_wyrand_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32n(max)
assert value >= 0
assert value < max
}
}
}
fn test_wyrand_u64n() {
max := u64(379091181005)
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_wyrand_u32_in_range() {
max := 484468466
min := 316846
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_wyrand_u64_in_range() {
max := u64(216468454685163)
min := u64(6848646868)
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_wyrand_int31() {
max_u31 := 0x7FFFFFFF
sign_mask := 0x80000000
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int31()
assert value >= 0
assert value <= max_u31
// This statement ensures that the sign bit is zero
assert (value & sign_mask) == 0
}
}
}
fn test_wyrand_int63() {
max_u63 := i64(0x7FFFFFFFFFFFFFFF)
sign_mask := i64(0x8000000000000000)
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int63()
assert value >= 0
assert value <= max_u63
assert (value & sign_mask) == 0
}
}
}
fn test_wyrand_intn() {
max := 2525642
for seed in seeds {
rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.intn(max)
assert value >= 0
assert value < max
}
}
}
fn test_wyrand_i64n() {
max := i64(3246727724653636)
for seed in seeds {
rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64n(max)
assert value >= 0
assert value < max
}
}
}
fn test_wyrand_int_in_range() {
min := -4252
max := 1034
for seed in seeds {
rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.int_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_wyrand_i64_in_range() {
min := i64(-24095)
max := i64(324058)
for seed in seeds {
rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.i64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_wyrand_f32() {
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_wyrand_f64() {
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < 1.0
}
}
}
fn test_wyrand_f32n() {
max := f32(357.0)
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= 0.0
assert value < max
}
}
}
fn test_wyrand_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= 0.0
assert value < max
}
}
}
fn test_wyrand_f32_in_range() {
min := f32(-24.0)
max := f32(125.0)
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32()
assert value >= min
assert value < max
}
}
}
fn test_wyrand_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := rand.WyRandRNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64()
assert value >= min
assert value < max
}
}
}