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Dev checkpoint - testing lookup tables

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Cian Hughes
2023-09-15 09:34:15 +01:00
parent 14d057e4ff
commit a9b671986e
27 changed files with 771 additions and 411 deletions
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39
src/fastmath.rs
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@@ -1,12 +1,13 @@
//! A collection of fast (often approximate) mathematical functions for accelerating mathematical functions
// Optimisation note: lookup tables become faster when calculation takes > ~1ms
// Optimisation note: lookup tables become faster when calculation takes > ~400us
use std::f32::consts as f32_consts;
use std::f64::consts as f64_consts;
// use crate::lookup::*;
use crate::lookup::lookup_table::EndoCosLookupTable;
use crate::lookup::{EndoCosLookupTable, EndoSinLookupTable};
const SIN_LOOKUP_F32: EndoSinLookupTable<f32> = EndoSinLookupTable::<f32>::new();
const SIN_LOOKUP_F64: EndoSinLookupTable<f64> = EndoSinLookupTable::<f64>::new();
const COS_LOOKUP_F32: EndoCosLookupTable<f32> = EndoCosLookupTable::<f32>::new();
const COS_LOOKUP_F64: EndoCosLookupTable<f64> = EndoCosLookupTable::<f64>::new();
@@ -18,6 +19,25 @@ const V_SCALE_F32: f32 = 8388608.0; // the largest possible mantissa of an f32
const V_SCALE_F64: f64 = 4503599627370496.0; // the largest possible mantissa of an f64
pub trait LookupSin {
fn lookup_sin(self: Self) -> Self;
}
impl LookupSin for f64 {
#[inline]
fn lookup_sin(self: Self) -> f64 {
// Look up the value in the table
SIN_LOOKUP_F64.lookup(self)
}
}
impl LookupSin for f32 {
#[inline]
fn lookup_sin(self: Self) -> f32 {
// Look up the value in the table
SIN_LOOKUP_F32.lookup(self)
}
}
pub trait LookupCos {
fn lookup_cos(self: Self) -> Self;
}
@@ -118,15 +138,4 @@ impl FastSigmoid for f64 {
const ONE: f64 = 1.0;
(ONE + (-self).fast_exp()).recip()
}
}
// functions for testing the accuracy of fast functions against builtin functions
#[inline]
pub fn sigmoid_builtin_f32(p: f32) -> f32 {
(1. + (-p).exp()).recip()
}
#[inline]
pub fn sigmoid_builtin_f64(p: f64) -> f64 {
(1. + (-p).exp()).recip()
}
}