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Use an external crate for fast approximate math functions.

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This commit is contained in:
Nathan Vegdahl 2020-12-26 10:03:35 +09:00
parent 4cfc051260
commit 6586b38dc9
5 changed files with 344 additions and 352 deletions
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1
Cargo.toml
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@ -36,6 +36,7 @@ rustc-serialize = "0.3"
scoped_threadpool = "0.1"
time = "0.1"
glam = {git="https://github.com/bitshifter/glam-rs.git", rev="0f314f99", default-features=false, features=["approx"]}
fastapprox = "0.3"
# Local crate dependencies
[dependencies.bvh_order]

2
LICENSE.md
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@ -1,6 +1,6 @@
## Psychopath
With the exception of files under `psychoblend/` and `sub_crates/`, and any code explicitly excepted in code comments, this project is licensed under the GPLv3 as follows:
With the exception of files under `psychoblend/` and `sub_crates/`, this project is licensed under the GPLv3 as follows:
Copyright (c) 2020 Nathan Vegdahl

28
licenses/MIT.txt
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@ -1,19 +1,19 @@
Copyright <YEAR> <COPYRIGHT HOLDER>
Copyright (c) 2020 Nathan Vegdahl
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

44
src/math.rs
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@ -188,64 +188,34 @@ pub fn probit(n: f32, width: f32) -> f32 {
x as f32 * width
}
//----------------------------------------------------------------
// Adapted to Rust from https://code.google.com/archive/p/fastapprox/
pub fn fast_ln(x: f32) -> f32 {
use std::mem::transmute_copy;
let mut y = unsafe { transmute_copy::<f32, u32>(&x) as f32 };
y *= 8.262_958_288_192_749_0e-8;
y - 87.989_971_088
fastapprox::fast::ln(x)
}
pub fn fast_pow2(p: f32) -> f32 {
use std::mem::transmute_copy;
let offset: f32 = if p < 0.0 { 1.0 } else { 0.0 };
let clipp: f32 = if p < -126.0 { -126.0 } else { p };
let w: i32 = clipp as i32;
let z: f32 = clipp - w as f32 + offset;
let i: u32 = ((1 << 23) as f32
* (clipp + 121.274_057_5 + 27.728_023_3 / (4.842_525_68 - z) - 1.490_129_07 * z))
as u32;
unsafe { transmute_copy::<u32, f32>(&i) }
fastapprox::fast::pow2(p)
}
pub fn fast_log2(x: f32) -> f32 {
use std::mem::transmute_copy;
let xi = unsafe { transmute_copy::<f32, u32>(&x) };
let y = xi as f32 * 1.192_092_895_507_812_5e-7;
let mx = unsafe { transmute_copy::<u32, f32>(&((xi & 0x007F_FFFF) | 0x3f00_0000)) };
y - 124.225_514_99 - 1.498_030_302 * mx - 1.725_879_99 / (0.352_088_706_8 + mx)
fastapprox::fast::log2(x)
}
pub fn fast_exp(p: f32) -> f32 {
fast_pow2(f32::consts::LOG2_E * p)
fastapprox::fast::exp(p)
}
pub fn fast_pow(x: f32, p: f32) -> f32 {
fast_pow2(p * fast_log2(x))
fastapprox::fast::pow(x, p)
}
pub fn faster_pow2(p: f32) -> f32 {
use std::mem::transmute_copy;
let clipp: f32 = if p < -126.0 { -126.0 } else { p };
let i: u32 = ((1 << 23) as f32 * (clipp + 126.942_695_04)) as u32;
unsafe { transmute_copy::<u32, f32>(&i) }
fastapprox::faster::pow2(p)
}
pub fn faster_exp(p: f32) -> f32 {
faster_pow2(f32::consts::LOG2_E * p)
fastapprox::faster::exp(p)
}
// End of adapted code
//----------------------------------------------------------------
#[cfg(test)]