Struct PowerTransformer 

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

An unfitted power transformer using the Yeo-Johnson method.

Calling Fit::fit estimates an optimal lambda per feature (via grid search over a range of lambda values) and returns a FittedPowerTransformer that can transform new data.

Examples

use ferrolearn_preprocess::PowerTransformer;
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::array;

let pt = PowerTransformer::<f64>::new();
let x = array![[1.0, 2.0], [3.0, 4.0], [5.0, 6.0]];
let fitted = pt.fit(&x, &()).unwrap();
let transformed = fitted.transform(&x).unwrap();

Implementations

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

pub fn new() -> Self

Create a new PowerTransformer with standardization enabled (default).

pub fn without_standardize() -> Self

Create a new PowerTransformer with standardization disabled.

pub fn standardize(&self) -> bool

Whether standardization is enabled.

Trait Implementations

impl<F: Clone> Clone for PowerTransformer<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for PowerTransformer<F>

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

Formats the value using the given formatter.

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

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

Fit the transformer by estimating the optimal lambda per feature.

Uses Brent’s method to minimize the negative log-likelihood on the interval [-3, 3], selecting the lambda that maximises the log-likelihood of the Yeo-Johnson transformed column following a normal distribution.

Errors

Returns FerroError::InsufficientSamples if the input has zero rows.

type Fitted = FittedPowerTransformer<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 PowerTransformer<F>

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

Fit the transformer on x and return the transformed output 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> PipelineTransformer<F> for PowerTransformer<F>

fn fit_pipeline( &self, x: &Array2<F>, _y: &Array1<F>, ) -> Result<Box<dyn FittedPipelineTransformer<F>>, FerroError>

Fit the transformer using the pipeline interface.

Errors

Propagates errors from Fit::fit.

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

Implement Transform on the unfitted transformer to satisfy the FitTransform: Transform supertrait bound.

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.