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|
import math
import rand
import rand.pcg32
import rand.seed
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 := pcg32.PCG32RNG{}
rng.seed(seed_data)
for i in 0 .. 20 {
randoms[i] = rng.u32n(u32(bound))
}
return randoms
}
fn test_pcg32_reproducibility() {
seed_data := seed.time_seed_array(4)
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 {
r1 := randoms1[i]
r2 := randoms2[i]
assert r1 == r2
}
}
// 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 := pcg32.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(mut rng pcg32.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 := pcg32.PCG32RNG{}
rng.seed(seed)
for range in ranges {
check_uniformity_u64(mut rng, u64(range))
}
}
}
fn check_uniformity_f64(mut rng pcg32.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 := pcg32.PCG32RNG{}
rng.seed(seed)
check_uniformity_f64(mut rng)
}
}
fn test_pcg32_u32n() {
max := u32(16384)
for seed in seeds {
mut rng := pcg32.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 := pcg32.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 := u32(484468466)
min := u32(316846)
for seed in seeds {
mut rng := pcg32.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.u32_in_range(u32(min), u32(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 := pcg32.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 := int(0x7FFFFFFF)
sign_mask := int(0x80000000)
for seed in seeds {
mut rng := pcg32.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 := pcg32.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 {
mut rng := pcg32.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 {
mut rng := pcg32.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 {
mut rng := pcg32.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 {
mut rng := pcg32.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 := pcg32.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 := pcg32.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 := pcg32.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32n(max)
assert value >= 0.0
assert value < max
}
}
}
fn test_pcg32_f64n() {
max := 1.52e6
for seed in seeds {
mut rng := pcg32.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64n(max)
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 := pcg32.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f32_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_pcg32_f64_in_range() {
min := -548.7
max := 5015.2
for seed in seeds {
mut rng := pcg32.PCG32RNG{}
rng.seed(seed)
for _ in 0 .. range_limit {
value := rng.f64_in_range(min, max)
assert value >= min
assert value < max
}
}
}
fn test_change_default_random_generator() {
rand.set_rng(pcg32.PCG32RNG{})
}
|
