Parameter Inference for Weak Lensing using Gaussian Processes and MOPED

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Title: Parameter Inference for Weak Lensing using Gaussian Processes and MOPED
Authors: Mootoovaloo, A
Heavens, AF
Jaffe, AH
Leclercq, F
Item Type: Journal Article
Abstract: In this paper, we propose a Gaussian Process (GP) emulator for the calculation both of tomographic weak lensing band powers, and of coefficients of summary data massively compressed with the MOPED algorithm. In the former case cosmological parameter inference is accelerated by a factor of ∼10–30 compared with Boltzmann solver class applied to KiDS-450 weak lensing data. Much larger gains of order 103 will come with future data, and MOPED with GPs will be fast enough to permit the Limber approximation to be dropped, with acceleration in this case of ∼105. A potential advantage of GPs is that an error on the emulated function can be computed and this uncertainty incorporated into the likelihood. However, it is known that the GP error can be unreliable when applied to deterministic functions, and we find, using the Kullback–Leibler divergence between the emulator and class likelihoods, and from the uncertainties on the parameters, that agreement is better when the GP uncertainty is not used. In future, weak lensing surveys such as Euclid, and the Legacy Survey of Space and Time, will have up to ∼104 summary statistics, and inference will be correspondingly more challenging. However, since the speed of MOPED is determined not the number of summary data, but by the number of parameters, MOPED analysis scales almost perfectly, provided that a fast way to compute the theoretical MOPED coefficients is available. The GP provides such a fast mechanism.
Issue Date: 1-Sep-2020
Date of Acceptance: 13-Jul-2020
DOI: 10.1093/mnras/staa2102
ISSN: 0035-8711
Publisher: Royal Astronomical Society
Start Page: 2213
End Page: 2226
Journal / Book Title: Monthly Notices of the Royal Astronomical Society
Volume: 497
Issue: 2222
Copyright Statement: © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record is available online at:
Keywords: astro-ph.CO
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
Notes: 16 pages, 11 figures
Publication Status: Published
Open Access location:
Online Publication Date: 2020-07-17
Appears in Collections:Physics