Shared Rust kernels

`ported/cosh`

All modules · quoted at commit 9e1884369a67 of DnaCalc/DnaCalc. Comments are the source's own.

cosh_kernel · 8 lines · calc-func/src/ported/cosh.rs on GitHub

pub fn cosh_kernel(n: f64) -> f64 {
    // Live Excel 16.0 b20326 Range.Value2: COSH(x)=(EXP(x)+EXP(-x))/2
    // 40/40, including spilled EXP cells and E/2+EXP(-x)/2. libm cosh is
    // 1 ULP off Excel at 0.001, 0.01, and 10.
    let e = crate::ported::excel_numeric::excel_exp(n);
    let em = crate::ported::excel_numeric::excel_exp(-n);
    crate::ported::excel_numeric::excel_x87_add(e, em) / 2.0
}

Used by 4 functions.