Dimensionality✓ Mathematical
◆ The PatternFinding the directions of maximum variance for dimensionality reduction
PCA finds the axes along which data varies the most. These are the eigenvectors of the covariance matrix.
C = (1/n)·XᵀX Cv = λv
C = covariance matrix | v = eigenvector | λ = eigenvalue (variance explained)
// 2D data with principal components — adjust correlation
Correlation0.70
PC1 explains—
PC2 explains—