arXiv Machine Learning By Jan Blechschmidt, Oliver G. Ernst, Moritz Poguntke, Bj\"orn Sprungk

Flow Matching for Fast Posterior Sampling in Bayesian Inverse Problems

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The paper introduces flow matching as an amortized alternative to Markov chain Monte Carlo for sampling from posterior distributions in Bayesian inverse problems. By training a transport map on joint samples of parameters and data, the method produces independent approximate posterior samples for any observation at negligible online cost, eliminating the need for new likelihood evaluations. The authors provide accuracy estimates in total‑variation distance and Kullback‑Leibler divergence, propose a hybrid Metropolized sampler for exactness, and validate the approach on examples such as electrical impedance tomography and a likelihood‑free Lotka‑Volterra model.

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