Shared Rust kernels

`ported/bessel_rational`

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

polynomial · 3 lines · calc-func/src/ported/bessel_rational.rs on GitHub

fn polynomial(x: f64, coefficients: &[f64]) -> f64 {
    polynomial_with(x, coefficients, |a, b| a * b, |a, b| a + b)
}

Used by 2 functions.

polynomial_with · 12 lines · calc-func/src/ported/bessel_rational.rs on GitHub

fn polynomial_with(
    x: f64,
    coefficients: &[f64],
    multiply: impl Fn(f64, f64) -> f64,
    add: impl Fn(f64, f64) -> f64,
) -> f64 {
    let mut value = *coefficients.last().unwrap();
    for &coefficient in coefficients[..coefficients.len() - 1].iter().rev() {
        value = add(multiply(x, value), coefficient);
    }
    value
}

Used by 3 functions.

j0 · 4 lines · calc-func/src/ported/bessel_rational.rs on GitHub

pub(super) fn j0(x: f64) -> f64 {
    let square = x * x;
    polynomial(square, J0_NUM) / polynomial(square, J0_DEN)
}

Used by 2 functions.

j1 · 4 lines · calc-func/src/ported/bessel_rational.rs on GitHub

pub(super) fn j1(x: f64) -> f64 {
    let square = x * x;
    (x * polynomial(square, J1_NUM)) / polynomial(square, J1_DEN)
}

Used by 2 functions.