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remove faulty cosh implementation

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This commit is contained in:
Lukas Wirth 2018-07-14 20:51:39 +02:00
parent be219bee50
commit c6aad03ae4
2 changed files with 0 additions and 57 deletions
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45
library/compiler-builtins/libm/src/math/cosh.rs
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@ -1,45 +0,0 @@
use core::f64;
use super::exp;
use super::expm1;
use super::k_expo2;
pub fn cosh(mut x: f64) -> f64 {
let t: f64;
/* |x| */
let mut ui = x.to_bits();
ui &= !0u64;
x = f64::from_bits(ui);
let w = (ui >> 32) as u32;
/* |x| < log(2) */
if w < 0x3fe62e42 {
if w < 0x3ff00000 - (26 << 20) {
/* raise inexact if x!=0 */
force_eval!(x + f64::from_bits(0x4770000000000000));
return 1.0;
}
let t = expm1(x);
return 1.0 + t * t / (2.0 * (1.0 + t));
}
/* |x| < log(DBL_MAX) */
if w < 0x40862e42 {
t = exp(x);
/* note: if x>log(0x1p26) then the 1/t is not needed */
return 0.5 * (t + 1.0 / t);
}
/* |x| > log(DBL_MAX) or nan */
/* note: the result is stored to handle overflow */
t = k_expo2(x);
return t;
}
#[cfg(test)]
mod tests {
#[test]
fn sanity_check() {
assert_eq!(super::cosh(1.1), 1.6685185538222564);
}
}

12
library/compiler-builtins/libm/src/math/k_expo2.rs
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@ -1,12 +0,0 @@
use super::exp;
const K: u32 = 2043;
const KLN2: f64 = 1416.0996898839683;
#[inline]
pub(crate) fn k_expo2(x: f64) -> f64 {
/* note that k is odd and scale*scale overflows */
let scale = f64::from_bits((((0x3ff + K / 2) << 20) as u64) << 32);
/* exp(x - k ln2) * 2**(k-1) */
return exp(x - KLN2) * scale * scale;
}