Struct KNNImputer 

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

An unfitted KNN imputer.

Calling Fit::fit stores the training data and returns a FittedKNNImputer that can impute missing values in new data.

Parameters

• n_neighbors — number of nearest neighbors to use (default 5).
• weights — how to weight neighbor contributions (default Uniform).

Examples

use ferrolearn_preprocess::knn_imputer::{KNNImputer, KNNWeights};
use ferrolearn_core::traits::{Fit, Transform};
use ndarray::array;

let imputer = KNNImputer::<f64>::new(2, KNNWeights::Uniform);
let x = array![[1.0, 2.0], [3.0, 4.0], [5.0, f64::NAN]];
let fitted = imputer.fit(&x, &()).unwrap();
let out = fitted.transform(&x).unwrap();
assert!(!out[[2, 1]].is_nan());

Implementations

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

pub fn new(n_neighbors: usize, weights: KNNWeights) -> Self

Create a new KNNImputer with the given parameters.

pub fn n_neighbors(&self) -> usize

Return the number of neighbors.

pub fn weights(&self) -> KNNWeights

Return the weighting strategy.

Trait Implementations

impl<F: Clone> Clone for KNNImputer<F>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug> Debug for KNNImputer<F>

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

Formats the value using the given formatter.

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

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

Fit the imputer by storing the training data.

Errors

• FerroError::InsufficientSamples if the input has zero rows.
• FerroError::InvalidParameter if n_neighbors is zero or exceeds the number of samples.

type Fitted = FittedKNNImputer<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 KNNImputer<F>

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

Fit the imputer on x and return the imputed 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> Transform<ArrayBase<OwnedRepr<F>, Dim<[usize; 2]>>> for KNNImputer<F>

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

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

Always returns an error — the imputer 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.