Cadmium::Classifier::Tabular::DistanceMetric
Inherits Enum < Comparable < Value < Object
Distance metrics for calculating similarity between feature vectors.
Used primarily by KNN to find nearest neighbors.
Constants
Euclidean = 0
Euclidean distance: √Σ(aᵢ - bᵢ)² Most common distance metric, works well for most cases
Manhattan = 1
Manhattan distance: Σ|aᵢ - bᵢ| Also known as L1 distance or city block distance Less sensitive to outliers than Euclidean
Chebyshev = 2
Chebyshev distance: max|aᵢ - bᵢ| Also known as L∞ distance or chessboard distance Useful for grid-like data
Cosine = 3
Cosine distance: 1 - (a·b)/(||a||·||b||) Measures angular similarity, ignores magnitude Useful for high-dimensional data