NFMap: Topographic 2D Manifold Learning with Invertible Normalizing Flows
NFMAP is an invertible method that combines Generative Topographic Mapping's fixed grid prior with a normalizing flow to map data into a 2D space. It creates a navigable map and an off-manifold residual, ensuring full invertibility. This allows new points to be projected onto the map while providing an exact likelihood signal for data quality.