diff options
Diffstat (limited to 'vendor/rand-0.7.3/src/distributions/float.rs')
-rw-r--r-- | vendor/rand-0.7.3/src/distributions/float.rs | 307 |
1 files changed, 0 insertions, 307 deletions
diff --git a/vendor/rand-0.7.3/src/distributions/float.rs b/vendor/rand-0.7.3/src/distributions/float.rs deleted file mode 100644 index 0a45f3977..000000000 --- a/vendor/rand-0.7.3/src/distributions/float.rs +++ /dev/null @@ -1,307 +0,0 @@ -// Copyright 2018 Developers of the Rand project. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -//! Basic floating-point number distributions - -use crate::distributions::utils::FloatSIMDUtils; -use crate::distributions::{Distribution, Standard}; -use crate::Rng; -use core::mem; -#[cfg(feature = "simd_support")] use packed_simd::*; - -/// A distribution to sample floating point numbers uniformly in the half-open -/// interval `(0, 1]`, i.e. including 1 but not 0. -/// -/// All values that can be generated are of the form `n * ε/2`. For `f32` -/// the 24 most significant random bits of a `u32` are used and for `f64` the -/// 53 most significant bits of a `u64` are used. The conversion uses the -/// multiplicative method. -/// -/// See also: [`Standard`] which samples from `[0, 1)`, [`Open01`] -/// which samples from `(0, 1)` and [`Uniform`] which samples from arbitrary -/// ranges. -/// -/// # Example -/// ``` -/// use rand::{thread_rng, Rng}; -/// use rand::distributions::OpenClosed01; -/// -/// let val: f32 = thread_rng().sample(OpenClosed01); -/// println!("f32 from (0, 1): {}", val); -/// ``` -/// -/// [`Standard`]: crate::distributions::Standard -/// [`Open01`]: crate::distributions::Open01 -/// [`Uniform`]: crate::distributions::uniform::Uniform -#[derive(Clone, Copy, Debug)] -pub struct OpenClosed01; - -/// A distribution to sample floating point numbers uniformly in the open -/// interval `(0, 1)`, i.e. not including either endpoint. -/// -/// All values that can be generated are of the form `n * ε + ε/2`. For `f32` -/// the 23 most significant random bits of an `u32` are used, for `f64` 52 from -/// an `u64`. The conversion uses a transmute-based method. -/// -/// See also: [`Standard`] which samples from `[0, 1)`, [`OpenClosed01`] -/// which samples from `(0, 1]` and [`Uniform`] which samples from arbitrary -/// ranges. -/// -/// # Example -/// ``` -/// use rand::{thread_rng, Rng}; -/// use rand::distributions::Open01; -/// -/// let val: f32 = thread_rng().sample(Open01); -/// println!("f32 from (0, 1): {}", val); -/// ``` -/// -/// [`Standard`]: crate::distributions::Standard -/// [`OpenClosed01`]: crate::distributions::OpenClosed01 -/// [`Uniform`]: crate::distributions::uniform::Uniform -#[derive(Clone, Copy, Debug)] -pub struct Open01; - - -// This trait is needed by both this lib and rand_distr hence is a hidden export -#[doc(hidden)] -pub trait IntoFloat { - type F; - - /// Helper method to combine the fraction and a contant exponent into a - /// float. - /// - /// Only the least significant bits of `self` may be set, 23 for `f32` and - /// 52 for `f64`. - /// The resulting value will fall in a range that depends on the exponent. - /// As an example the range with exponent 0 will be - /// [2<sup>0</sup>..2<sup>1</sup>), which is [1..2). - fn into_float_with_exponent(self, exponent: i32) -> Self::F; -} - -macro_rules! float_impls { - ($ty:ident, $uty:ident, $f_scalar:ident, $u_scalar:ty, - $fraction_bits:expr, $exponent_bias:expr) => { - impl IntoFloat for $uty { - type F = $ty; - #[inline(always)] - fn into_float_with_exponent(self, exponent: i32) -> $ty { - // The exponent is encoded using an offset-binary representation - let exponent_bits: $u_scalar = - (($exponent_bias + exponent) as $u_scalar) << $fraction_bits; - $ty::from_bits(self | exponent_bits) - } - } - - impl Distribution<$ty> for Standard { - fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty { - // Multiply-based method; 24/53 random bits; [0, 1) interval. - // We use the most significant bits because for simple RNGs - // those are usually more random. - let float_size = mem::size_of::<$f_scalar>() as u32 * 8; - let precision = $fraction_bits + 1; - let scale = 1.0 / ((1 as $u_scalar << precision) as $f_scalar); - - let value: $uty = rng.gen(); - let value = value >> (float_size - precision); - scale * $ty::cast_from_int(value) - } - } - - impl Distribution<$ty> for OpenClosed01 { - fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty { - // Multiply-based method; 24/53 random bits; (0, 1] interval. - // We use the most significant bits because for simple RNGs - // those are usually more random. - let float_size = mem::size_of::<$f_scalar>() as u32 * 8; - let precision = $fraction_bits + 1; - let scale = 1.0 / ((1 as $u_scalar << precision) as $f_scalar); - - let value: $uty = rng.gen(); - let value = value >> (float_size - precision); - // Add 1 to shift up; will not overflow because of right-shift: - scale * $ty::cast_from_int(value + 1) - } - } - - impl Distribution<$ty> for Open01 { - fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> $ty { - // Transmute-based method; 23/52 random bits; (0, 1) interval. - // We use the most significant bits because for simple RNGs - // those are usually more random. - use core::$f_scalar::EPSILON; - let float_size = mem::size_of::<$f_scalar>() as u32 * 8; - - let value: $uty = rng.gen(); - let fraction = value >> (float_size - $fraction_bits); - fraction.into_float_with_exponent(0) - (1.0 - EPSILON / 2.0) - } - } - } -} - -float_impls! { f32, u32, f32, u32, 23, 127 } -float_impls! { f64, u64, f64, u64, 52, 1023 } - -#[cfg(feature = "simd_support")] -float_impls! { f32x2, u32x2, f32, u32, 23, 127 } -#[cfg(feature = "simd_support")] -float_impls! { f32x4, u32x4, f32, u32, 23, 127 } -#[cfg(feature = "simd_support")] -float_impls! { f32x8, u32x8, f32, u32, 23, 127 } -#[cfg(feature = "simd_support")] -float_impls! { f32x16, u32x16, f32, u32, 23, 127 } - -#[cfg(feature = "simd_support")] -float_impls! { f64x2, u64x2, f64, u64, 52, 1023 } -#[cfg(feature = "simd_support")] -float_impls! { f64x4, u64x4, f64, u64, 52, 1023 } -#[cfg(feature = "simd_support")] -float_impls! { f64x8, u64x8, f64, u64, 52, 1023 } - - -#[cfg(test)] -mod tests { - use super::*; - use crate::rngs::mock::StepRng; - - const EPSILON32: f32 = ::core::f32::EPSILON; - const EPSILON64: f64 = ::core::f64::EPSILON; - - macro_rules! test_f32 { - ($fnn:ident, $ty:ident, $ZERO:expr, $EPSILON:expr) => { - #[test] - fn $fnn() { - // Standard - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.gen::<$ty>(), $ZERO); - let mut one = StepRng::new(1 << 8 | 1 << (8 + 32), 0); - assert_eq!(one.gen::<$ty>(), $EPSILON / 2.0); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.gen::<$ty>(), 1.0 - $EPSILON / 2.0); - - // OpenClosed01 - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.sample::<$ty, _>(OpenClosed01), 0.0 + $EPSILON / 2.0); - let mut one = StepRng::new(1 << 8 | 1 << (8 + 32), 0); - assert_eq!(one.sample::<$ty, _>(OpenClosed01), $EPSILON); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.sample::<$ty, _>(OpenClosed01), $ZERO + 1.0); - - // Open01 - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.sample::<$ty, _>(Open01), 0.0 + $EPSILON / 2.0); - let mut one = StepRng::new(1 << 9 | 1 << (9 + 32), 0); - assert_eq!(one.sample::<$ty, _>(Open01), $EPSILON / 2.0 * 3.0); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.sample::<$ty, _>(Open01), 1.0 - $EPSILON / 2.0); - } - }; - } - test_f32! { f32_edge_cases, f32, 0.0, EPSILON32 } - #[cfg(feature = "simd_support")] - test_f32! { f32x2_edge_cases, f32x2, f32x2::splat(0.0), f32x2::splat(EPSILON32) } - #[cfg(feature = "simd_support")] - test_f32! { f32x4_edge_cases, f32x4, f32x4::splat(0.0), f32x4::splat(EPSILON32) } - #[cfg(feature = "simd_support")] - test_f32! { f32x8_edge_cases, f32x8, f32x8::splat(0.0), f32x8::splat(EPSILON32) } - #[cfg(feature = "simd_support")] - test_f32! { f32x16_edge_cases, f32x16, f32x16::splat(0.0), f32x16::splat(EPSILON32) } - - macro_rules! test_f64 { - ($fnn:ident, $ty:ident, $ZERO:expr, $EPSILON:expr) => { - #[test] - fn $fnn() { - // Standard - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.gen::<$ty>(), $ZERO); - let mut one = StepRng::new(1 << 11, 0); - assert_eq!(one.gen::<$ty>(), $EPSILON / 2.0); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.gen::<$ty>(), 1.0 - $EPSILON / 2.0); - - // OpenClosed01 - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.sample::<$ty, _>(OpenClosed01), 0.0 + $EPSILON / 2.0); - let mut one = StepRng::new(1 << 11, 0); - assert_eq!(one.sample::<$ty, _>(OpenClosed01), $EPSILON); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.sample::<$ty, _>(OpenClosed01), $ZERO + 1.0); - - // Open01 - let mut zeros = StepRng::new(0, 0); - assert_eq!(zeros.sample::<$ty, _>(Open01), 0.0 + $EPSILON / 2.0); - let mut one = StepRng::new(1 << 12, 0); - assert_eq!(one.sample::<$ty, _>(Open01), $EPSILON / 2.0 * 3.0); - let mut max = StepRng::new(!0, 0); - assert_eq!(max.sample::<$ty, _>(Open01), 1.0 - $EPSILON / 2.0); - } - }; - } - test_f64! { f64_edge_cases, f64, 0.0, EPSILON64 } - #[cfg(feature = "simd_support")] - test_f64! { f64x2_edge_cases, f64x2, f64x2::splat(0.0), f64x2::splat(EPSILON64) } - #[cfg(feature = "simd_support")] - test_f64! { f64x4_edge_cases, f64x4, f64x4::splat(0.0), f64x4::splat(EPSILON64) } - #[cfg(feature = "simd_support")] - test_f64! { f64x8_edge_cases, f64x8, f64x8::splat(0.0), f64x8::splat(EPSILON64) } - - #[test] - fn value_stability() { - fn test_samples<T: Copy + core::fmt::Debug + PartialEq, D: Distribution<T>>( - distr: &D, zero: T, expected: &[T], - ) { - let mut rng = crate::test::rng(0x6f44f5646c2a7334); - let mut buf = [zero; 3]; - for x in &mut buf { - *x = rng.sample(&distr); - } - assert_eq!(&buf, expected); - } - - test_samples(&Standard, 0f32, &[0.0035963655, 0.7346052, 0.09778172]); - test_samples(&Standard, 0f64, &[ - 0.7346051961657583, - 0.20298547462974248, - 0.8166436635290655, - ]); - - test_samples(&OpenClosed01, 0f32, &[0.003596425, 0.73460525, 0.09778178]); - test_samples(&OpenClosed01, 0f64, &[ - 0.7346051961657584, - 0.2029854746297426, - 0.8166436635290656, - ]); - - test_samples(&Open01, 0f32, &[0.0035963655, 0.73460525, 0.09778172]); - test_samples(&Open01, 0f64, &[ - 0.7346051961657584, - 0.20298547462974248, - 0.8166436635290656, - ]); - - #[cfg(feature = "simd_support")] - { - // We only test a sub-set of types here. Values are identical to - // non-SIMD types; we assume this pattern continues across all - // SIMD types. - - test_samples(&Standard, f32x2::new(0.0, 0.0), &[ - f32x2::new(0.0035963655, 0.7346052), - f32x2::new(0.09778172, 0.20298547), - f32x2::new(0.34296435, 0.81664366), - ]); - - test_samples(&Standard, f64x2::new(0.0, 0.0), &[ - f64x2::new(0.7346051961657583, 0.20298547462974248), - f64x2::new(0.8166436635290655, 0.7423708925400552), - f64x2::new(0.16387782224016323, 0.9087068770169618), - ]); - } - } -} |