v/vlib/rand/splitmix64_test.v

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import rand
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import math
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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)
)
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fn gen_randoms(seed_data []u32, bound int) []u64 {
bound_u64 := u64(bound)
mut randoms := [u64(0)].repeat(20)
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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() {
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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
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for i in 0 .. len {
assert randoms1[i] == randoms2[i]
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}
}
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// 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
}
}
}
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fn check_uniformity_u64(mut rng rand.SplitMix64RNG, range u64) {
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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 {
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check_uniformity_u64(mut rng, u64(range))
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}
}
}
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fn check_uniformity_f64(mut rng rand.SplitMix64RNG) {
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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)
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check_uniformity_f64(mut rng)
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}
}
fn test_splitmix64_u32n() {
max := 16384
for seed in seeds {
mut rng := rand.SplitMix64RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
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value := rng.u32n(u32(max))
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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 {
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value := rng.u32_in_range(u32(min), u32(max))
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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 {
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mut rng := rand.SplitMix64RNG{}
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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 {
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mut rng := rand.SplitMix64RNG{}
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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 {
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mut rng := rand.SplitMix64RNG{}
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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 {
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mut rng := rand.SplitMix64RNG{}
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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
}
}
}