pub fn log_eta(x: f64) -> f64 {
// 1e-6 ~ 0.00247, 1 - 1e-6 ~ 0.99752
// log_eta(1) = 0
(0.0024787521766663585 + 0.9975212478233336 * x).ln()
}
#[cfg(test)]
mod tests {
use super::*;
use rstest::*;
#[rstest]
#[case(1., 0.)]
#[case(0., -6.)]
fn test_log_eta(#[case] x: f64, #[case] expected: f64) {
assert_eq!(log_eta(x), expected);
}
}