Struct TargetEncoder 

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

An unfitted target encoder.

Takes a matrix of categorical integer features and a continuous (or binary) target vector at fit time. Each category is encoded as the smoothed mean of the target for that category.

Parameters

• smooth — smoothing factor (default 1.0). Higher values regularise more toward the global mean. Set to 0 for no smoothing.

Examples

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

let enc = TargetEncoder::<f64>::new(1.0);
let x = array![[0usize, 1], [0, 0], [1, 1], [1, 0]];
let y = array![1.0, 2.0, 3.0, 4.0];
let fitted = enc.fit(&x, &y).unwrap();
let out = fitted.transform(&x).unwrap();
assert_eq!(out.shape(), &[4, 2]);

Implementations

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

pub fn new(smooth: F) -> Self

Create a new TargetEncoder with the given smoothing factor.

pub fn smooth(&self) -> F

Return the smoothing factor.

Trait Implementations

impl<F: Clone> Clone for TargetEncoder<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for TargetEncoder<F>

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

Formats the value using the given formatter.

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

fn default() -> Self

Returns the “default value” for a type.

impl<F: Float + Send + Sync + 'static> Fit<ArrayBase<OwnedRepr<usize>, Dim<[usize; 2]>>, ArrayBase<OwnedRepr<F>, Dim<[usize; 1]>>> for TargetEncoder<F>

fn fit( &self, x: &Array2<usize>, y: &Array1<F>, ) -> Result<FittedTargetEncoder<F>, FerroError>

Fit the encoder by computing smoothed target means per category.

Errors

• FerroError::InsufficientSamples if the input has zero rows.
• FerroError::ShapeMismatch if x rows and y length differ.
• FerroError::InvalidParameter if smooth is negative.

type Fitted = FittedTargetEncoder<F>

The fitted model type returned by fit.

type Error = FerroError

The error type returned by fit.