gamlss_transform/transforms/
identity_positive.rs

1use crate::{TargetTransform, TransformError, map_slice_into, validate_positive};
2
3/// Identity transform that validates strictly positive targets.
4#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
5pub struct IdentityPositive;
6
7/// State for [`IdentityPositive`].
8#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
9pub struct IdentityPositiveState;
10
11impl TargetTransform for IdentityPositive {
12    type State = IdentityPositiveState;
13
14    fn fit(y: &[f64]) -> Result<Self::State, TransformError> {
15        validate_positive(y)?;
16        Ok(IdentityPositiveState)
17    }
18
19    #[inline(always)]
20    fn transform(_: &Self::State, y: f64) -> f64 {
21        y
22    }
23
24    #[inline(always)]
25    fn inverse(_: &Self::State, value: f64) -> f64 {
26        value
27    }
28
29    #[inline]
30    fn transform_slice(state: &Self::State, y: &[f64]) -> Result<Vec<f64>, TransformError> {
31        let mut out = vec![0.0; y.len()];
32        Self::transform_into(state, y, &mut out)?;
33        Ok(out)
34    }
35
36    #[inline]
37    fn transform_into(
38        state: &Self::State,
39        y: &[f64],
40        out: &mut [f64],
41    ) -> Result<(), TransformError> {
42        map_slice_into(y, out, validate_positive, |value| {
43            Self::transform(state, value)
44        })
45    }
46}
47
48#[cfg(test)]
49mod tests {
50    use crate::{IdentityPositive, TargetTransform, TransformError};
51
52    #[test]
53    fn rejects_non_positive_values() {
54        assert_eq!(
55            IdentityPositive::fit(&[-1.0]).unwrap_err(),
56            TransformError::NonPositiveValue
57        );
58    }
59
60    #[test]
61    fn leaves_positive_values_unchanged() {
62        let y = [1.0, 2.0];
63        let (state, transformed) = IdentityPositive::fit_transform(&y).unwrap();
64
65        assert_eq!(transformed, y);
66        assert_eq!(
67            IdentityPositive::inverse_slice(&state, &transformed).unwrap(),
68            y
69        );
70    }
71}
gamlss_transform/transforms/identity_positive.rs

gamlss_transform/transforms/
identity_positive.rs
