Reconstructing the universe with variational self-boosted sampling
نویسندگان
چکیده
Abstract Forward modeling approaches in cosmology have made it possible to reconstruct the initial conditions at beginning of Universe from observed survey data. However high dimensionality parameter space still poses a challenge explore full posterior, with traditional algorithms such as Hamiltonian Monte Carlo (HMC) being computationally inefficient due generating correlated samples and performance variational inference highly dependent on choice divergence (loss) function. Here we develop hybrid scheme, called self-boosted sampling (VBS) mitigate drawbacks both these by learning approximation for proposal distribution combine HMC. The is parameterized normalizing flow learnt generated fly, while proposals drawn reduce auto-correlation length MCMC chains. Our uses Fourier convolutions element-wise operations scale dimensions. We show that after short warm-up training phase, VBS generates better quality than simple VI reduces correlation phase factor 10–50 over using only HMC posterior 64 3 128 dimensional problems, larger gains signal-to-noise data observations. Hybrid online violates Markov property, retain asymptotic guarantees HMC, final use fixed propagate distribution.
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ژورنال
عنوان ژورنال: Journal of Cosmology and Astroparticle Physics
سال: 2023
ISSN: ['1475-7516', '1475-7508']
DOI: https://doi.org/10.1088/1475-7516/2023/03/059