compute_eigenvalues     Compute Eigenvalues of the Covariance Matrix
marchenko_pastur_bounds
                        Marchenko–Pastur Theoretical Bounds
plot_sigPCA             Plot PCA Eigenvalue Spectrum with
                        Marchenko–Pastur Bounds
plot_sigPCA_histogram   Plot PCA Eigenvalue Histogram with
                        Marchenko-Pastur Bounds
sigPCA                  Unified PCA Significance Wrapper
sigPCA_mp               PCA Significance Based on Marchenko–Pastur
                        Distribution
sigPCA_perm             PCA Significance via Permutation Test
