CARPool: fast, accurate computation of large-scale structure statistics by pairing costly and cheap cosmological simulations - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2021

CARPool: fast, accurate computation of large-scale structure statistics by pairing costly and cheap cosmological simulations

Résumé

To exploit the power of next-generation large-scale structure surveys, ensembles of numerical simulations are necessary to give accurate theoretical predictions of the statistics of observables. High-fidelity simulations come at a towering computational cost. Therefore, approximate but fast simulations, surrogates, are widely used to gain speed at the price of introducing model error. We propose a general method that exploits the correlation between simulations and surrogates to compute fast, reduced-variance statistics of large-scale structure observables without model error at the cost of only a few simulations. We call this approach Convergence Acceleration by Regression and Pooling (CARPool). In numerical experiments with intentionally minimal tuning, we apply CARPool to a handful of gadget-iii  N-body simulations paired with surrogates computed using COmoving Lagrangian Acceleration. We find ∼100-fold variance reduction even in the non-linear regime, up to |$k_\mathrm{max} \approx 1.2\, h {\rm Mpc^{-1}}$| for the matter power spectrum. CARPool realizes similar improvements for the matter bispectrum. In the nearly linear regime CARPool attains far larger sample variance reductions. By comparing to the 15 000 simulations from the Quijote suite, we verify that the CARPool estimates are unbiased, as guaranteed by construction, even though the surrogate misses the simulation truth by up to |$60{{\ \rm per\ cent}}$| at high k. Furthermore, even with a fully configuration-space statistic like the non-linear matter density probability density function, CARPool achieves unbiased variance reduction factors of up to ∼10, without any further tuning. Conversely, CARPool can be used to remove model error from ensembles of fast surrogates by combining them with a few high-accuracy simulations.
Fichier principal
Vignette du fichier
stab430.pdf (6.58 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-02959517 , version 1 (06-07-2023)

Identifiants

Citer

Nicolas Chartier, Benjamin Wandelt, Yashar Akrami, Francisco Villaescusa-Navarro. CARPool: fast, accurate computation of large-scale structure statistics by pairing costly and cheap cosmological simulations. Monthly Notices of the Royal Astronomical Society, 2021, 503 (2), pp.1897-1914. ⟨10.1093/mnras/stab430⟩. ⟨hal-02959517⟩
239 Consultations
15 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More