Gadget3 on GPUs with OpenACC

Ragagnin, Antonio; Dolag, Klaus; Wagner, Mathias; Gheller, Claudio; Roffler, Conradin; Goz, David; Hubber, David; Arth, Alexander

doi:10.48550/arxiv.2003.10850

Cited by 2 publications

(1 citation statement)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The N-body simulations are computationally expensive, as they require computing the JCAP02(2023)050 evolution of billions of particles in very small time steps. Several codes have been developed and highly optimized to make these simulations fast [64,[80][81][82][83]. Moreover, box replication schemes are often employed to create a larger simulation with higher particle density, but with the same repeating particle distribution, taking advantage of the periodic boundary conditions.…”

Section: Map-level Theory Prediction Using Simulationsmentioning

confidence: 99%

CosmoGridV1: a simulated 𝗐CDM theory prediction for map-level cosmological inference

Kacprzak

Fluri

Schneider

et al. 2023

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

We present CosmoGridV1: a large set of lightcone simulations for map-level cosmological inference with probes of large scale structure. It is designed for cosmological parameter measurement based on Stage-III photometric surveys with non-Gaussian statistics and machine learning. CosmoGridV1 spans the wCDM model by varying Ωm, σ 8, w 0, H 0, n s, Ω b , and assumes three degenerate neutrinos with fixed ∑ mν = 0.06 eV. This space is covered by 2500 grid points on a Sobol sequence. At each grid point, we run 7 simulations with PkdGrav3 and store 69 particle maps at nside = 2048 up to z = 3.5, as well as halo catalog snapshots. The fiducial cosmology has 200 independent simulations, along with their stencil derivatives. An important part of CosmoGridV1 is the benchmark set of 28 simulations, which include larger boxes, higher particle counts, and higher redshift resolution of shells. They allow for testing if new types of analyses are sensitive to choices made in CosmoGridV1. We add baryon feedback effects on the map level, using shell-based baryon correction model. The shells are used to create maps of weak gravitational lensing, intrinsic alignment, and galaxy clustering, using the UFalcon code. The main part of CosmoGridV1 are the raw particle count shells that can be used to create full-sky maps for a given n(z). We also release projected maps for a Stage-III forecast, as well as maps used previously in KiDS-1000 deep learning constraints with CosmoGridV1. The data is available at http://www.cosmogrid.ai/.

show abstract

Section: Map-level Theory Prediction Using Simulationsmentioning

confidence: 99%

CosmoGridV1: a simulated 𝗐CDM theory prediction for map-level cosmological inference

Kacprzak

Fluri

Schneider

et al. 2023

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

show abstract

Adapting arepo-rt for exascale computing: GPU acceleration and efficient communication

Zier,

Kannan,

Smith

et al. 2024

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Radiative transfer (RT) is a crucial ingredient for self-consistent modelling of numerous astrophysical phenomena across cosmic history. However, on-the-fly integration into radiation-hydrodynamics (RHD) simulations is computationally demanding, particularly due to the stringent time-stepping conditions and increased dimensionality inherent in multi-frequency collisionless Boltzmann physics. The emergence of exascale supercomputers, equipped with extensive CPU cores and GPU accelerators, offers new opportunities for enhancing RHD simulations. We present the first steps towards optimizing AREPO-RT for such high-performance computing environments. We implement a novel node-to-node communication strategy that utilizes shared memory to substitute intra-node communication with direct memory access. Furthermore, combining multiple inter-node messages into a single message substantially enhances network bandwidth utilization and performance for large-scale simulations on modern supercomputers. The single-message node-to-node approach also improves performance on smaller-scale machines with less optimized networks. Furthermore, by transitioning all RT-related calculations to GPUs, we achieve a significant computational speedup of around 15 for standard benchmarks compared to the original CPU implementation. As a case study, we perform cosmological RHD simulations of the Epoch of Reionization, employing a similar setup as the THESAN project. In this context, RT becomes sub-dominant such that even without modifying the core AREPO codebase, there is an overall threefold improvement in efficiency. The advancements presented here have broad implications, potentially transforming the complexity and scalability of future simulations for a wide variety of astrophysical studies. Our work serves as a blueprint for porting similar simulation codes based on unstructured resolution elements to GPU-centric architectures.

show abstract

Gadget3 on GPUs with OpenACC

Cited by 2 publications

References 10 publications

CosmoGridV1: a simulated 𝗐CDM theory prediction for map-level cosmological inference

CosmoGridV1: a simulated 𝗐CDM theory prediction for map-level cosmological inference

Adapting arepo-rt for exascale computing: GPU acceleration and efficient communication

Contact Info

Product

Resources

About