Struct StandardScaler 

pub struct StandardScaler { /* private fields */ }

Standardizes features by removing the mean and scaling to unit variance.

Formula

For each feature column x:

z = (x - μ) / σ

where:

• μ is the mean of the feature
• σ is the standard deviation (σ² + ε)¹ᐟ²
• ε is a small constant for numerical stability

When to Use

• When features have different scales
• For algorithms sensitive to feature magnitude (not tree-based)
• When you want zero-centered data

Notes

Trees are scale-invariant, so scaling is optional for gradient boosting. However, it can help with regularization and numerical stability.

Implementations

impl StandardScaler

pub fn new() -> Self

Creates a new unsc fitted StandardScaler with default epsilon.

pub fn with_epsilon(epsilon: f64) -> Self

Creates a new StandardScaler with custom epsilon.

Parameters

• epsilon: Small constant added to denominator for numerical stability. Set to 1e-8 by default. Increase for very small features.

pub fn is_fitted(&self) -> bool

Returns true if the scaler has been fitted.

Trait Implementations

impl Clone for StandardScaler

fn clone(&self) -> StandardScaler

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StandardScaler

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

Formats the value using the given formatter.

impl Default for StandardScaler

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for StandardScaler

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Scaler for StandardScaler

fn fit(&mut self, data: &FeatureMatrix) -> DataResult<()>

Learns scaling parameters from the training data.

fn transform(&self, data: &FeatureMatrix) -> DataResult<FeatureMatrix>

Applies learned transformation to data.

fn fit_transform(&mut self, data: &FeatureMatrix) -> DataResult<FeatureMatrix>

Fits and transforms in a single operation.

impl Serialize for StandardScaler

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.