The irony of a paper titled “Exact Gaussian Processes on a Million Data Points” Gemini explains why MPDOK outperforms the paper arXiv:1903.08114 1. The "Exact" Illusion: Why Wang et al. Had to Approximate To understand why they compromised, we have to look at what BlackBox Matrix-Matrix (BBMM) and Conjugate Gradient (CG) methods actually do. The baseline paper uses an iterative Krylov solver (Conjugate Gradient) to solve linear systems like K−1yK^{-1}y without ever… https://felixquinihildebet.wordpress.com/2026/07/14/the-irony-of-a-paper-titled-exact-gaussian-processes-on-a-million-data-points/