“…The latter refers to the image and pre-image mapping between the original and latent space (e.g., see analysis in Chiavazzo, Gear, Dsilva, Rabin, & Kevrekidis, 2014). This so-called "out-of-sample" extension interpolates general function values on manifold point clouds and, therefore, has to handle large input data dimensions (Coifman & Lafon, 2006b;Fernández, Rabin, Fishelov, & Dorronsoro, 2020;Rabin & Coifman, 2012). In datafold, out-of-sample extensions are imple-mented efficiently, so that interpolated function values for millions of points can be computed in seconds on a standard desktop computer.…”