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https://github.com/vlang/v.git
synced 2023-08-10 21:13:21 +03:00
rand: simplify rand.PRNG, move to optional types for error handling (#13570)
This commit is contained in:
@@ -5,7 +5,6 @@ module sys
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import math.bits
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import rand.seed
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import rand.constants
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// Implementation note:
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// ====================
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@@ -76,204 +75,6 @@ pub fn (r SysRNG) u64() u64 {
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return result
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}
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// r.u32n(max) returns a pseudorandom u32 value that is guaranteed to be less than max
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[inline]
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pub fn (r SysRNG) u32n(max u32) u32 {
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if max == 0 {
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eprintln('max must be positive integer')
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exit(1)
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}
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// Owing to the pigeon-hole principle, we can't simply do
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// val := rng.u32() % max.
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// It'll wreck the properties of the distribution unless
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// max evenly divides 2^32. So we divide evenly to
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// the closest power of two. Then we loop until we find
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// an int in the required range
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bit_len := bits.len_32(max)
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if bit_len == 32 {
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for {
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value := r.u32()
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if value < max {
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return value
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}
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}
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} else {
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mask := (u32(1) << (bit_len + 1)) - 1
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for {
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value := r.u32() & mask
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if value < max {
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return value
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}
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}
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}
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return u32(0)
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}
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// r.u64n(max) returns a pseudorandom u64 value that is guaranteed to be less than max
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[inline]
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pub fn (r SysRNG) u64n(max u64) u64 {
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if max == 0 {
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eprintln('max must be positive integer')
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exit(1)
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}
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// Similar procedure for u64s
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bit_len := bits.len_64(max)
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if bit_len == 64 {
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for {
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value := r.u64()
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if value < max {
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return value
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}
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}
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} else {
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mask := (u64(1) << (bit_len + 1)) - 1
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for {
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value := r.u64() & mask
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if value < max {
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return value
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}
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}
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}
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return u64(0)
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}
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// r.u32n(min, max) returns a pseudorandom u32 value that is guaranteed to be in [min, max)
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[inline]
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pub fn (r SysRNG) u32_in_range(min u32, max u32) u32 {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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return min + r.u32n(max - min)
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}
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// r.u64n(min, max) returns a pseudorandom u64 value that is guaranteed to be in [min, max)
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[inline]
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pub fn (r SysRNG) u64_in_range(min u64, max u64) u64 {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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return min + r.u64n(max - min)
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}
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// r.int() returns a pseudorandom 32-bit int (which may be negative)
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[inline]
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pub fn (r SysRNG) int() int {
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return int(r.u32())
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}
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// r.i64() returns a pseudorandom 64-bit i64 (which may be negative)
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[inline]
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pub fn (r SysRNG) i64() i64 {
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return i64(r.u64())
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}
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// r.int31() returns a pseudorandom 31-bit int which is non-negative
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[inline]
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pub fn (r SysRNG) int31() int {
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return int(r.u32() & constants.u31_mask) // Set the 32nd bit to 0.
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}
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// r.int63() returns a pseudorandom 63-bit int which is non-negative
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[inline]
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pub fn (r SysRNG) int63() i64 {
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return i64(r.u64() & constants.u63_mask) // Set the 64th bit to 0.
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}
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// r.intn(max) returns a pseudorandom int that lies in [0, max)
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[inline]
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pub fn (r SysRNG) intn(max int) int {
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if max <= 0 {
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eprintln('max has to be positive.')
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exit(1)
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}
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return int(r.u32n(u32(max)))
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}
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// r.i64n(max) returns a pseudorandom i64 that lies in [0, max)
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[inline]
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pub fn (r SysRNG) i64n(max i64) i64 {
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if max <= 0 {
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eprintln('max has to be positive.')
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exit(1)
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}
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return i64(r.u64n(u64(max)))
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}
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// r.int_in_range(min, max) returns a pseudorandom int that lies in [min, max)
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[inline]
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pub fn (r SysRNG) int_in_range(min int, max int) int {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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// This supports negative ranges like [-10, -5) because the difference is positive
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return min + r.intn(max - min)
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}
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// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
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[inline]
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pub fn (r SysRNG) i64_in_range(min i64, max i64) i64 {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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return min + r.i64n(max - min)
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}
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// r.f32() returns a pseudorandom f32 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
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[inline]
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pub fn (r SysRNG) f32() f32 {
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return f32(r.u32()) / constants.max_u32_as_f32
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}
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// r.f64() returns a pseudorandom f64 value between 0.0 (inclusive) and 1.0 (exclusive) i.e [0, 1)
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[inline]
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pub fn (r SysRNG) f64() f64 {
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return f64(r.u64()) / constants.max_u64_as_f64
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}
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// r.f32n() returns a pseudorandom f32 value in [0, max)
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[inline]
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pub fn (r SysRNG) f32n(max f32) f32 {
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if max <= 0 {
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eprintln('max has to be positive.')
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exit(1)
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}
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return r.f32() * max
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}
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// r.f64n() returns a pseudorandom f64 value in [0, max)
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[inline]
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pub fn (r SysRNG) f64n(max f64) f64 {
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if max <= 0 {
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eprintln('max has to be positive.')
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exit(1)
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}
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return r.f64() * max
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}
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// r.f32_in_range(min, max) returns a pseudorandom f32 that lies in [min, max)
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[inline]
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pub fn (r SysRNG) f32_in_range(min f32, max f32) f32 {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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return min + r.f32n(max - min)
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}
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// r.i64_in_range(min, max) returns a pseudorandom i64 that lies in [min, max)
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[inline]
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pub fn (r SysRNG) f64_in_range(min f64, max f64) f64 {
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if max <= min {
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eprintln('max must be greater than min')
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exit(1)
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}
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return min + r.f64n(max - min)
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}
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// free should be called when the generator is no longer needed
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[unsafe]
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pub fn (mut rng SysRNG) free() {
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@@ -1,4 +1,5 @@
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import math
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import rand
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import rand.sys
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const (
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@@ -13,7 +14,7 @@ const (
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inv_sqrt_12 = 1.0 / math.sqrt(12)
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)
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fn get_n_randoms(n int, r sys.SysRNG) []int {
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fn get_n_randoms(n int, mut r rand.PRNG) []int {
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mut ints := []int{cap: n}
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for _ in 0 .. n {
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ints << r.int()
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@@ -28,51 +29,40 @@ fn test_sys_rng_reproducibility() {
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// seed for another batch of data.
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for seed in seeds {
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seed_data := [seed]
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mut r1 := sys.SysRNG{}
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mut r2 := sys.SysRNG{}
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mut r1 := &rand.PRNG(&sys.SysRNG{})
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mut r2 := &rand.PRNG(&sys.SysRNG{})
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r1.seed(seed_data)
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ints1 := get_n_randoms(value_count, r1)
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ints1 := get_n_randoms(value_count, mut r1)
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r2.seed(seed_data)
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ints2 := get_n_randoms(value_count, r2)
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ints2 := get_n_randoms(value_count, mut r2)
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assert ints1 == ints2
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}
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}
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// TODO: use the `in` syntax and remove this function
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// after generics has been completely implemented
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fn found(value u64, arr []u64) bool {
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for item in arr {
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if value == item {
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return true
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}
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}
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return false
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}
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fn test_sys_rng_variability() {
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// If this test fails and if it is certainly not the implementation
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// at fault, try changing the seed values. Repeated values are
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// improbable but not impossible.
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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mut values := []u64{cap: value_count}
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for i in 0 .. value_count {
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value := rng.u64()
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assert !found(value, values)
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assert value !in values
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assert values.len == i
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values << value
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}
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}
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}
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fn check_uniformity_u64(rng sys.SysRNG, range u64) {
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fn check_uniformity_u64(mut rng rand.PRNG, range u64) {
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range_f64 := f64(range)
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expected_mean := range_f64 / 2.0
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mut variance := 0.0
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for _ in 0 .. sample_size {
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diff := f64(rng.u64n(range)) - expected_mean
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diff := f64(rng.u64n(range) or { panic("Couldn't obtain u64") }) - expected_mean
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variance += diff * diff
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}
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variance /= sample_size - 1
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@@ -88,15 +78,15 @@ fn test_sys_rng_uniformity_u64() {
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ranges := [14019545, 80240, 130]
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for range in ranges {
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check_uniformity_u64(rng, u64(range))
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check_uniformity_u64(mut rng, u64(range))
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}
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}
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}
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fn check_uniformity_f64(rng sys.SysRNG) {
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fn check_uniformity_f64(mut rng rand.PRNG) {
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expected_mean := 0.5
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mut variance := 0.0
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for _ in 0 .. sample_size {
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@@ -114,9 +104,9 @@ fn test_sys_rng_uniformity_f64() {
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// The f64 version
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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check_uniformity_f64(rng)
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check_uniformity_f64(mut rng)
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}
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}
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@@ -124,10 +114,10 @@ fn test_sys_rng_u32n() {
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max := u32(16384)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.u32n(max)
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value := rng.u32n(max) or { panic("Couldn't obtain u32") }
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assert value >= 0
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assert value < max
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}
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@@ -138,10 +128,10 @@ fn test_sys_rng_u64n() {
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max := u64(379091181005)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.u64n(max)
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value := rng.u64n(max) or { panic("Couldn't obtain u64") }
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assert value >= 0
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assert value < max
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}
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@@ -153,10 +143,10 @@ fn test_sys_rng_u32_in_range() {
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min := u32(316846)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.u32_in_range(min, max)
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value := rng.u32_in_range(min, max) or { panic("Couldn't obtain u32 in range") }
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assert value >= min
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assert value < max
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}
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@@ -168,10 +158,10 @@ fn test_sys_rng_u64_in_range() {
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min := u64(6848646868)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.u64_in_range(min, max)
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value := rng.u64_in_range(min, max) or { panic("Couldn't obtain u64 in range") }
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assert value >= min
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assert value < max
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}
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@@ -182,10 +172,10 @@ fn test_sys_rng_intn() {
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max := 2525642
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.intn(max)
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value := rng.intn(max) or { panic("Couldn't obtain int") }
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assert value >= 0
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assert value < max
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}
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@@ -196,10 +186,10 @@ fn test_sys_rng_i64n() {
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max := i64(3246727724653636)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.i64n(max)
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value := rng.i64n(max) or { panic("Couldn't obtain i64") }
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assert value >= 0
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assert value < max
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}
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@@ -211,10 +201,10 @@ fn test_sys_rng_int_in_range() {
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max := 23054962
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.int_in_range(min, max)
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value := rng.int_in_range(min, max) or { panic("Couldn't obtain int in range") }
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assert value >= min
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assert value < max
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}
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@@ -226,10 +216,10 @@ fn test_sys_rng_i64_in_range() {
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max := i64(324058)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.i64_in_range(min, max)
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value := rng.i64_in_range(min, max) or { panic("Couldn't obtain i64 in range") }
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assert value >= min
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assert value < max
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}
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@@ -241,7 +231,7 @@ fn test_sys_rng_int31() {
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sign_mask := int(0x80000000)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.int31()
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@@ -258,7 +248,7 @@ fn test_sys_rng_int63() {
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sign_mask := i64(0x8000000000000000)
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.int63()
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@@ -272,7 +262,7 @@ fn test_sys_rng_int63() {
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fn test_sys_rng_f32() {
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for seed in seeds {
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seed_data := [seed]
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mut rng := sys.SysRNG{}
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mut rng := &rand.PRNG(&sys.SysRNG{})
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rng.seed(seed_data)
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for _ in 0 .. range_limit {
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value := rng.f32()
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@@ -285,7 +275,7 @@ fn test_sys_rng_f32() {
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fn test_sys_rng_f64() {
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||||
for seed in seeds {
|
||||
seed_data := [seed]
|
||||
mut rng := sys.SysRNG{}
|
||||
mut rng := &rand.PRNG(&sys.SysRNG{})
|
||||
rng.seed(seed_data)
|
||||
for _ in 0 .. range_limit {
|
||||
value := rng.f64()
|
||||
@@ -299,10 +289,10 @@ fn test_sys_rng_f32n() {
|
||||
max := f32(357.0)
|
||||
for seed in seeds {
|
||||
seed_data := [seed]
|
||||
mut rng := sys.SysRNG{}
|
||||
mut rng := &rand.PRNG(&sys.SysRNG{})
|
||||
rng.seed(seed_data)
|
||||
for _ in 0 .. range_limit {
|
||||
value := rng.f32n(max)
|
||||
value := rng.f32n(max) or { panic("Couldn't obtain f32") }
|
||||
assert value >= 0.0
|
||||
assert value < max
|
||||
}
|
||||
@@ -313,10 +303,10 @@ fn test_sys_rng_f64n() {
|
||||
max := 1.52e6
|
||||
for seed in seeds {
|
||||
seed_data := [seed]
|
||||
mut rng := sys.SysRNG{}
|
||||
mut rng := &rand.PRNG(&sys.SysRNG{})
|
||||
rng.seed(seed_data)
|
||||
for _ in 0 .. range_limit {
|
||||
value := rng.f64n(max)
|
||||
value := rng.f64n(max) or { panic("Couldn't obtain f64") }
|
||||
assert value >= 0.0
|
||||
assert value < max
|
||||
}
|
||||
@@ -328,10 +318,10 @@ fn test_sys_rng_f32_in_range() {
|
||||
max := f32(125.0)
|
||||
for seed in seeds {
|
||||
seed_data := [seed]
|
||||
mut rng := sys.SysRNG{}
|
||||
mut rng := &rand.PRNG(&sys.SysRNG{})
|
||||
rng.seed(seed_data)
|
||||
for _ in 0 .. range_limit {
|
||||
value := rng.f32_in_range(min, max)
|
||||
value := rng.f32_in_range(min, max) or { panic("Couldn't obtain f32 in range") }
|
||||
assert value >= min
|
||||
assert value < max
|
||||
}
|
||||
@@ -343,10 +333,10 @@ fn test_sys_rng_f64_in_range() {
|
||||
max := 5015.2
|
||||
for seed in seeds {
|
||||
seed_data := [seed]
|
||||
mut rng := sys.SysRNG{}
|
||||
mut rng := &rand.PRNG(&sys.SysRNG{})
|
||||
rng.seed(seed_data)
|
||||
for _ in 0 .. range_limit {
|
||||
value := rng.f64_in_range(min, max)
|
||||
value := rng.f64_in_range(min, max) or { panic("Couldn't obtain f64 in range") }
|
||||
assert value >= min
|
||||
assert value < max
|
||||
}
|
||||
|
Reference in New Issue
Block a user