
Title
Computational Scientist 
Email
gardner48@llnl.gov 
Phone
(925) 4239937 
Organization
COMPCASC DIVCENTER FOR APPLIED SCIENTIFIC COMPUTING DIVISION
Dr. David Gardner is a computational scientist in the Scientific Computing group within the Center for Applied Scientific Computing (CASC) at Lawrence Livermore National Laboratory (LLNL). His work focuses on the development and implementation of accurate and efficient time integration methods and nonlinear solvers for simulating multiscale, multiphysics applications on high performance computing systems. As part of the Exascale Computing Project and FASTMath SciDAC Institute, he contributes to the SUNDIALS software library of time integrators and nonlinear solvers.
In prior projects Dr. Gardner has worked on the Energy Exascale Earth System Model (E3SM) to improve the numerical convergence of atmospheric physics processes, evaluate the accuracy and efficiency of implicitexplicit time integrators for nonhydrostatic atmospheric dynamics, design and implement preconditioners for fully implicit integration methods for hydrostatic atmospheric dynamics, and develop time integrators for coupled atmospheric physics processes. He has also worked on fully implicit time integration methods and nonlinear solvers for dislocation dynamics in the Parallel Dislocation Simulator (ParaDiS) and filtering methods for noisy data in hybrid continuumatomistic simulations.
Dr. Gardner joined CASC in July 2014 as a postdoctoral researcher after completing his Ph.D. in Computational and Applied Mathematics at Southern Methodist University (SMU).
ORCID: 0000000279938282
ResearcherID: T40942017
Scopus Author ID: 56494048400
Refereed Publications
 D. J. Gardner, D. R. Reynolds, C. S. Woodward, and C. J. Balos, "Enabling new flexibility in the SUNDIALS suite of nonlinear and differential/algebraic equation solvers," ACM Transactions on Mathematical Software (TOMS), 2022. [DOI]
 S. Lockhart, D. J. Gardner, C. S. Woodward, S. Thomas, and L. N. Olson, "Performance of low synchronization orthogonalization methods in Anderson accelerated fixed point solvers," Proceedings of the 2022 SIAM Conference on Parallel Processing for Scientific Computing, Society for Industrial and Applied Mathematics, 2022. [DOI]
 C. J. Balos, D. J. Gardner, C. S. Woodward, and D. R. Reynolds, "Enabling GPU accelerated computing in the SUNDIALS time integration library," Parallel Computing, 2021. [DOI]
 H. Wan, C. S. Woodward, S. Zhang, C. J. Vogl, P. Stinis, D. J. Gardner, P. J. Rash, X. Zeng, V. E. Larson, and B. Singh, "Improving time step convergence in an atmosphere model with simplified physics: The impacts of closure assumption and process coupling," Journal of Advances in Modeling Earth Systems, 2020. [DOI]
 I. Karlin, et al., "Preparation and optimization of a diverse workload for a largescale heterogeneous system," Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis, 2019. [DOI]
 D. J. Gardner, J. E. Guerra, F. P. Hamon, D. R. Reynolds, P. A. Ullrich, and C. S. Woodward, "Implicitexplicit (IMEX) RungeKutta methods for nonhydrostatic atmospheric models," Geoscientific Model Development, 2018. [DOI]
 K. J. Evans, R. K. Archibald, D. J. Gardner, M. R. Norman, M. A. Taylor, C. S. Woodward, and P. A. Worley, "Performance analysis of fully explicit and fully implicit solvers within a spectral element shallowwater atmosphere model," The International Journal of High Performance Computing Applications, 2017. [DOI]
 D. J. Gardner and D. R. Reynolds, "Filters for improvement of multiscale data from atomistic simulations," Multiscale Modeling & Simulation, 2017. [DOI]
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, G. Hommes, S. Aubry, and A. Arsenlis, "Implicit integration methods for dislocation dynamics," Modelling and Simulation in Materials Science and Engineering, 2015. [DOI]
 C. S. Woodward, D. J. Gardner, and K. J. Evans, "On the Use of Finite Difference MatrixVector Products in NewtonKrylov Solvers for Implicit Climate Dynamics with Spectral Elements," Procedia Computer Science, 2015. [DOI]
Invited Presentations
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, and C. J. Balos, Multirate Integrators in SUNDIALS, International Conference on Scientific Computation and Differential Equations, University of Innsbruck, Innsbruck, Austria, July 22 – 26, 2019.
 D. J. Gardner, P. Rasch, P. Stinis, C. J. Vogl, H. Wan, C. S. Woodward, S. Zhang, Assessing and Improving the Numerical Solution of Atmospheric Physics in E3SM, SIAM Conference on Mathematical & Computational Issues in the Geosciences, Houston, TX, March 11 – 14, 2019.
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, S. Peles, and C. J. Balos, The SUNDIALS Suite of Time Integrators and Nonlinear Solvers: Preparing for Exascale Computing, SIAM Conference on Computational Science and Engineering, Spokane, WA, Feburary 25 – March 1, 2019.
 D. J. Gardner, C. S. Woodward, H. Wan, C. J. Vogl, and P. Rasch, Assessing and Improving the Numerical Solution of Atmospheric Physics in E3SM, SIAM Conference on the Mathematics of Planted Earth, Philadelphia, PA, September 13 – 15, 2018.
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, S. Peles, J. Loffeld, and C. J. Balos, The SUNDIALS Suite of Time Integrators and Nonlinear Solvers, Bout++ Workshop, Livermore, CA, August 14 – 17, 2018.
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, and S. Peles, SUNDIALS Suite of Time Integrators and Nonlinear Solvers (poster), SIAM Annual Meeting, Portland, OR, July 9 – 13, 2018.
 D. J. Gardner, J. E. Guerra, F. P. Hamon, D. R. Reynolds, P. A. Ullrich, and C. S. Woodward, ImplicitExplicit Time Integration Methods for Nonhydrostatic Atmospheric Models, IMAGe 2017 Theme of the Year: Workshop on Multiscale Geoscience Numerics, NCAR Mesa Lab, Boulder, CO, May 16 – 19, 2017.
 D. J. Gardner, J. E. Guerra, F. P. Hamon, D. R. Reynolds, P. A. Ullrich, and C. S. Woodward, ImplicitExplicit Time Integration Methods for Nonhydrostatic Atmospheric Models, SIAM Conference on Mathematics of Planet Earth, Philadelphia, PA, September 30 – October 2, 2016.
 D. J. Gardner, C. S. Woodward, P. M. Caldwell, and K. J. Evans, Advanced Time Integration Methods for Atmospheric Physics (poster), AXICCS Workshop, Rockville, MD, September 12 – 13, 2016.
 D. J. Gardner, R. Archibald, K. J. Evans, P. A. Ullrich, C. S. Woodward, and P. H. Worley, Scalable Nonlinear Solvers and Preconditioners in Climate Applications, SIAM Conference on Parallel Processing for Scientific Computing, Paris, France, April 12 – 15, 2016.
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, K. Mohror, G. Hommes, S. Aubry, M. Rhee, and A. Arsenlis, Implicit Integration Methods for Dislocation Dynamics, Numerical Methods for LargeScale Nonlinear Problems and Their Applications, ICERM, Providence, RI, August 31 – September 4, 2015.
 D. J. Gardner, P. M. Caldwell, J. M. Sexton, and C. S. Woodward, Numerical Errors in Coupling Micro and Macrophysics in the Community Atmosphere Model, SIAM Conference on Mathematical and Computational Issues in the Geosciences, Stanford University, Stanford, CA, June 29 – July 2, 2015.
 D. J. Gardner, K. J. Evans, P. A. Lott, A. Salinger, and C. S. Woodward, Preconditioners for Implicit Atmospheric Climate Simulations in the Community Atmosphere Model, SIAM Conference on Computational Science and Engineering, Salt Lake City, UT, March 14 – 18, 2015.
Presentations
 D. J. Gardner, C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, and C. J. Balos, The SUNDIALS Suite of Nonlinear and Differential / Algebraic Equation Solvers (poster), International Congress on Industrial and Applied Mathematics, Valencia, Spain, July 15 – 19, 2019.
 D. J. Gardner and D.R. Reynolds, Improving the Computational Efficiency of Multiscale Simulations with Filtering, SIAM Conference on Computational Science and Engineering, Atlanta, GA, February 27 – March 3, 2017.
 D. J. Gardner, J. E. Guerra, F. P. Hamon, D. R. Reynolds, P. A. Ullrich, and C. S. Woodward, ImplicitExplicit Time Integration Methods for Nonhydrostatic Atmospheric Models (poster), AGU Fall Meeting, San Francisco, CA, December 12 – 16, 2016.
 D. J. Gardner and D. R. Reynolds, Filters for the Improvement of Multiscale Data from Atomistic Simulations, SIAM Annual Meeting, Boston, MA, July 11 – 15, 2016.
 D. J. Gardner, P. M. Caldwell, and C. S. Woodward, Advanced Time Integration Methods for Atmospheric Physics (poster), SIAM Annual Meeting, Boston, MA, July 11 – 15, 2016.
 D. J. Gardner and D. R. Reynolds, Filters for the Improvement of Multiscale Data from Atomistic Simulations (poster), SIAM Conference on Parallel Processing for Scientific Computing, Paris, France, April 12 – 15, 2016.
 D. J. Gardner, R. Archibald, K. J. Evans, and C. S. Woodward, Implicit Time Stepping and Preconditioning for Global Atmospheric Dynamics in Climate Simulation, Fourteenth Copper Mountain Conference on Iterative Methods, Copper Mountain, CO, March 20 – 25, 2016.
 D. J. Gardner, K. J. Evans, C. S. Woodward, R. Archibald, and P. H. Worley, Implicit Time Stepping and Preconditioning for Atmospheric Dynamics in the Community Atmosphere Model (poster), AGU Fall Meeting, San Francisco, CA, December 14 – 18, 2015.
 C. S. Woodward, D. R. Reynolds, A. C. Hindmarsh, L. E. Banks, and D. J. Gardner, SUNDIALS: Suite of Nonlinear and Differential / Algebraic equation solvers (poster), 2015 Scientific Discovery through Advanced Computing (SciDAC3) Principal Investigator Meeting, Bethesda, MD, July 22 – 24, 2015.
 D. J. Gardner, P. M. Caldwell, J. M. Sexton, and C. S. Woodward, Numerical Errors in Coupling Micro and Macrophysics in the Community Atmosphere Model (poster), AGU Fall Meeting, San Francisco, CA, December 15 – 19, 2014.