diff options
Diffstat (limited to 'v_windows/v/vlib/rand/sys/system_rng_test.v')
| -rw-r--r-- | v_windows/v/vlib/rand/sys/system_rng_test.v | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/v_windows/v/vlib/rand/sys/system_rng_test.v b/v_windows/v/vlib/rand/sys/system_rng_test.v new file mode 100644 index 0000000..638ed10 --- /dev/null +++ b/v_windows/v/vlib/rand/sys/system_rng_test.v @@ -0,0 +1,354 @@ +import math +import rand.sys + +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 sys.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] + mut r1 := sys.SysRNG{} + mut r2 := sys.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] + mut rng := sys.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 sys.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] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for range in ranges { + check_uniformity_u64(rng, u64(range)) + } + } +} + +fn check_uniformity_f64(rng sys.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] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + check_uniformity_f64(rng) + } +} + +fn test_sys_rng_u32n() { + max := u32(16384) + for seed in seeds { + seed_data := [seed] + mut rng := sys.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] + mut rng := sys.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 := u32(484468466) + min := u32(316846) + for seed in seeds { + seed_data := [seed] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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 := int(0x7FFFFFFF) + sign_mask := int(0x80000000) + for seed in seeds { + seed_data := [seed] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.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] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f32n(max) + assert value >= 0.0 + assert value < max + } + } +} + +fn test_sys_rng_f64n() { + max := 1.52e6 + for seed in seeds { + seed_data := [seed] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f64n(max) + 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] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f32_in_range(min, max) + 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] + mut rng := sys.SysRNG{} + rng.seed(seed_data) + for _ in 0 .. range_limit { + value := rng.f64_in_range(min, max) + assert value >= min + assert value < max + } + } +} |