Building halo merger trees from the Q continuum simulation

Esteban Rangel, Nicholas Frontiere, Salman Habib, Katrin Heitmann, Wei-Keng Liao, Ankit Agrawal, Alok Nidhi Choudhary

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Cosmological N-body simulations rank among the most computationally intensive efforts today. A key challenge is the analysis of structure, substructure, and the merger history for many billions of compact particle clusters, called halos. Effectively representing the merging history of halos is essential for many galaxy formation models used to generate synthetic sky catalogs, an important application of modern cosmological simulations. Generating realistic mock catalogs requires computing the halo formation history from simulations with large volumes and billions of halos over many time steps, taking hundreds of terabytes of analysis data. We present fast parallel algorithms for producing halo merger trees and tracking halo substructure from a single-level, density-based clustering algorithm. Merger trees are created from analyzing the halo-particle membership function in adjacent snapshots, and substructure is identified by tracking the »cores» of merging halos - sets of particles near the halo center. Core tracking is performed after creating merger trees and uses the relationships found during tree construction to associate substructures with hosts. The algorithms are implemented with MPI and evaluated on a Cray XK7 supercomputer using up to 16,384 processes on data from HACC, a modern cosmological simulation framework. We present results for creating merger trees from 101 analysis snapshots taken from the Q Continuum, a large volume, high mass resolution, cosmological simulation evolving half a trillion particles.

Original languageEnglish (US)
Title of host publicationProceedings - 24th IEEE International Conference on High Performance Computing, HiPC 2017
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages398-407
Number of pages10
ISBN (Electronic)9781538622933
DOIs
StatePublished - Feb 7 2018
Event24th IEEE International Conference on High Performance Computing, HiPC 2017 - Jaipur, India
Duration: Dec 18 2017Dec 21 2017

Publication series

NameProceedings - 24th IEEE International Conference on High Performance Computing, HiPC 2017
Volume2017-December

Other

Other24th IEEE International Conference on High Performance Computing, HiPC 2017
CountryIndia
CityJaipur
Period12/18/1712/21/17

Keywords

  • Cosmological Nbody Simulations
  • Dark Matter Halos
  • Merger Trees

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Hardware and Architecture
  • Modeling and Simulation

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  • Cite this

    Rangel, E., Frontiere, N., Habib, S., Heitmann, K., Liao, W-K., Agrawal, A., & Choudhary, A. N. (2018). Building halo merger trees from the Q continuum simulation. In Proceedings - 24th IEEE International Conference on High Performance Computing, HiPC 2017 (pp. 398-407). (Proceedings - 24th IEEE International Conference on High Performance Computing, HiPC 2017; Vol. 2017-December). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/HiPC.2017.00052