Ongoing verification of a multiphysics community code: FLASH

Dubey, Anshu; Weide, Klaus; Lee, Dong‐Wook; Bachan, John; Daley, Chris; Olofin, Samuel; Taylor, Noel T.; Rich, Paul M.; Reid, Lynn B.

doi:10.1002/spe.2220

Cited by 11 publications

(11 citation statements)

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“…The creation of test suites for different platforms and the management of test suite execution are done with a custom test framework known as FlashTest [23], which was developed into its current form with version 3 of the FLASH code. It evolved from a much simpler automated system developed at version 2 out of necessity due to the lack of Fortran-based testing frameworks at the time.…”

Section: Evaluation Of Historic Processes and Updatesmentioning

confidence: 99%

Distillation of Best Practices from Refactoring FLASH for Exascale

et al. 2020

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FLASH is a multiphysics software package that was created in 1998 by combining three preexisting packages and has undergone three major revisions. Software design and engineering practices were integrated early in the development and maintenance processes of FLASH, and these processes have evolved strongly at each of the revisions. As high-performance computing enters the age of exascale, challenges along the orthogonal axes of node-level hardware and solver heterogeneity force developers of complex multiphysics software to consider a software architecture overhaul. Because of the nature and scope of necessary changes, an effort to refactor and grow the architecture of the FLASH code has been launched as a separate software project. For this project to succeed, its development team must evaluate, improve, and modernize software processes and policies to meet the unique challenges posed by the exascale era. We describe here our experiences, lessons we have learned, and the methods that we have developed as part of this ongoing project. Within the context of the challenges posed by exascale, we review the FLASH design approach as well as some of the main software engineering processes and tools that have been implemented or updated throughout the lifetime of FLASH. Modernization applied to these processes and tools is also detailed. Reviewing and reevaluating the FLASH experience of establishing and updating software design and engineering practices have been helpful in understanding the needs of the project as it transitions to exascale and in planning the transition. We find that our historical design methodology is still important and relevant. We also believe that using a mixture of plan-based and agile methods is still the best for our project and is in accord with the guidance found in the literature. We present a section on inferences and lessons learned related to software design and engineering practices.

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Section: Evaluation Of Historic Processes and Updatesmentioning

confidence: 99%

Distillation of Best Practices from Refactoring FLASH for Exascale

et al. 2020

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“…The comparisons typically consist of simulations performed at increasing spatial and/or temporal resolutions to confirm convergence of the simulation to the correct answer. Details of these tests have appeared in the literature, and many of the tests are incorporated into automated regression testing of Flash (Calder et al, 2002;Dwarkadas et al, 2005;Hearn et al, 2007;Dubey et al, 2009Dubey et al, , 2015.…”

Section: Approach To Verification and Validationmentioning

confidence: 99%

“…As of this writing, Flash has had 20 years of development by generations of scientists. Much of this effort has been subjected to rigorous V&V (Calder et al, 2002;Timmes et al, 2004;Dwarkadas et al, 2005;Hearn et al, 2007;Dubey et al, 2009Dubey et al, , 2015Townsley et al, 2016). In this contribution, we present two examples of validating the Flash code and post-processing toolkit for astrophysical applications.…”

Section: Validation Examplesmentioning

confidence: 99%

Astrophysical Validation

Calder¹,

Townsley²

2019

Simulation Foundations, Methods and Applications

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We present examples of validating components of an astrophysical simulation code. Problems of stellar astrophysics are multi-dimensional and involve physics acting on large ranges of length and time scales that are impossible to include in macroscopic models on present computational resources. Simulating these events thus necessitates the development of sub-grid-scale models and the capability to post-process simulations with higher-fidelity methods. We present an overview of the problem of validating astrophysical models and simulations illustrated with two examples. First, we present a study aimed at validating hydrodynamics with high energy density laboratory experiments probing shocks and fluid instabilities. Second, we present an effort at validating code modules for use in both macroscopic simulations of astrophysical events and for post processing Lagrangian tracer particles to calculate detailed abundances from thermonuclear reactions occurring during an event.

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“…There is some discussion of the issue in the computer science literature [53,54] but less in domain-specific journals. Some lessons on multiphysics software verification can be found in a recent paper [55].…”

Section: Writing Tests For Scientific Softwarementioning

confidence: 99%