Continuous Simulation Data Stream: A dynamical timescale-dependent output scheme for simulations

Astronomy and Computing, vol. 41, pp. 100659

Abstract

Exa-scale simulations are on the horizon but almost no new design for the output has been proposed in recent years. In simulations using individual time steps, the traditional snapshots are over resolving particles/cells with large time steps and are under resolving the particles/cells with short time steps. Therefore, they are unable to follow fast events and use efficiently the storage space. The Continuous Simulation Data Stream (CSDS) is designed to decrease this space while providing an accurate state of the simulation at any time. It takes advantage of the individual time step to ensure the same relative accuracy for all the particles. The outputs consist of a single file representing the full evolution of the simulation. Within this file, the particles are written independently and at their own frequency. Through the interpolation of the records, the state of the simulation can be recovered at any point in time. In this paper, we show that the CSDS can reduce the storage space by 2.76x for the same accuracy than snapshots or increase the accuracy by 67.8x for the same storage space whilst retaining an acceptable reading speed for analysis. By using interpolation between records, the CSDS provides the state of the simulation, with a high accuracy, at any time. This should largely improve the analysis of fast events such as supernovae and simplify the construction of light-cone outputs.

Authors 3

1. Loïc Hausammann corresponding

   École Polytechnique Fédérale de Lausanne

   Affiliation as printed

   Laboratoire d’Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauvergny, Switzerland

   Laboratoire d'Astrophysique, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauvergny, Switzerland

2. Pedro Gonnet

   Google (Switzerland)

   Affiliation as printed

   Google Switzerland, 8002 Zürich, Switzerland

3. Matthieu Schaller Aachen Leiden Observatory Lorentz Institute for Theoretical Physics

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, The Netherlands

   Lorentz Institute for Theoretical Physics, Leiden University, PO Box 9506, NL-2300 RA Leiden, The Netherlands