Struct SplineTransformer 

pub struct SplineTransformer<F> { /* private fields */ }

An unfitted spline transformer.

Calling Fit::fit computes the knot positions and returns a FittedSplineTransformer that generates B-spline basis functions.

Parameters

• n_knots — number of interior knots (default 5).
• degree — degree of the B-spline (default 3, i.e. cubic).
• knots — knot placement strategy (default Uniform).

The number of output columns per feature is n_knots + degree - 1.

Examples

use ferrolearn_preprocess::spline_transformer::{SplineTransformer, KnotStrategy};
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::array;

let st = SplineTransformer::<f64>::new(5, 3, KnotStrategy::Uniform);
let x = array![[0.0], [0.25], [0.5], [0.75], [1.0]];
let fitted = st.fit(&x, &()).unwrap();
let out = fitted.transform(&x).unwrap();
// 5 + 3 - 1 = 7 basis columns per feature
assert_eq!(out.ncols(), 7);

Implementations

impl<F: Float + Send + Sync + 'static> SplineTransformer<F>

pub fn new(n_knots: usize, degree: usize, knots: KnotStrategy) -> Self

Create a new SplineTransformer.

pub fn n_knots(&self) -> usize

Return the number of interior knots.

pub fn degree(&self) -> usize

Return the B-spline degree.

pub fn knot_strategy(&self) -> KnotStrategy

Return the knot placement strategy.

Trait Implementations

impl<F: Clone> Clone for SplineTransformer<F>

fn clone(&self) -> SplineTransformer<F>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<F: Debug> Debug for SplineTransformer<F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<F: Float + Send + Sync + 'static> Default for SplineTransformer<F>

fn default() -> Self

Returns the “default value” for a type.

impl<F: Float + Send + Sync + 'static> Fit<ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>, ()> for SplineTransformer<F>

fn fit( &self, x: &Array2<F>, _y: &(), ) -> Result<FittedSplineTransformer<F>, FerroError>

Fit by computing knot positions for each feature.

Errors

• FerroError::InsufficientSamples if the input has fewer than 2 rows.
• FerroError::InvalidParameter if n_knots < 2 or degree is 0.

type Fitted = FittedSplineTransformer<F>

The fitted model type returned by fit.

type Error = FerroError

The error type returned by fit.

impl<F: Float + Send + Sync + 'static> FitTransform<ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>> for SplineTransformer<F>

fn fit_transform(&self, x: &Array2<F>) -> Result<Array2<F>, FerroError>

Fit and transform in one step.

Errors

Returns an error if fitting fails.

type FitError = FerroError

The error type for the combined fit-transform operation.

impl<F: Float + Send + Sync + 'static> Transform<ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>> for SplineTransformer<F>

Implement Transform on the unfitted transformer.

fn transform(&self, _x: &Array2<F>) -> Result<Array2<F>, FerroError>

Always returns an error — the transformer must be fitted first.

type Output = ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>

The transformed output type.

type Error = FerroError

The error type returned by transform.