Complete comparison of three dimensionality reduction methods on 43,019 LAMOST DR5 stellar spectra: PCA (linear), UMAP (topological) and t-SNE (probabilistic). Hyperparameters, results, Procrustes stability and HDBSCAN clusters.
AstroSpectro results in two separate studies: unsupervised dimensionality reduction (PCA, UMAP, t-SNE, HDBSCAN) on the PHY-3500 dataset (G1, 43,019 spectra), and the reference XGBoost classifier with its SHAP attribution on the 350k-spectrum generation (G2, run v6, which includes Gaia/photometric features).
UMAP topological projection and unsupervised HDBSCAN clustering of the stellar spectral feature space.