Large-Scale GW Calculations on Pre-Exascale HPC Systems

ORAL

Abstract

Large-scale GW calculations are required to accurately describe excited state phenomena in materials, which is critical for the design of novel devices in many fields. However, application of the GW method to complex systems is often limited due to the high computational cost. Reduced time to solution can be achieved through novel methods, algorithms and optimal implementations on modern HPC systems. We demonstrate these capabilities utilizing a highly-optimized version of the BerkeleyGW software package for HPC many-core architectures. The developed code, tested on Cori@NERSC (a Cray XC40, Xeon-Phi powered system), is capable of scaling to the full-machine, using a high fraction of peak performance and achieving excellent time to solution for systems of thousands of atoms. A high fraction of peak and good parallel scaling comes from an improved data layout where the computationally intensive work at the node level is cast as large ZGEMM operations, combined with a ring-based communication scheme, which avoids collective operations and allows overlapping with computation.

*Work supported by the Center for Computational Study of Excited-State Phenomena in Energy Materials (C2SEPEM) at LBL, funded by the U.S.DOE under Contract No. DE-AC02-05CH11231.

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Presenters

  • Mauro Del Ben

    • Lawrence Berkeley National Labratory
    • Computational Research Division, Lawrence Berkeley National Laboratory

Authors

  • Mauro Del Ben

    • Lawrence Berkeley National Labratory
    • Computational Research Division, Lawrence Berkeley National Laboratory

  • Felipe H. da Jornada

    • Department of Physics, UC Berkeley and Materials Sciences Division, Lawrence Berkeley National Lab
    • Materials Sciences Division, Lawrence Berkeley National Laboratory & Department of Physics, University of California at Berkeley

  • Andrew Canning

    • Lawrence Berkeley National Labratory
    • Computational Research Division, Lawrence Berkeley National Laboratory

  • Nathan Wichmann

    • Cray Inc.

  • Karthik Raman

    • Intel Corporation

  • Ruchira Sasanka

    • Intel Corporation

  • Chao Yang

    • Lawrence Berkeley National Laboratory
    • Computational Research Division, Lawrence Berkeley National Laboratory

  • Steven Louie

    • Physics, University of California, Berkeley
    • University of California, Berkeley
    • Physics, Univ of California - Berkeley
    • Univ of California - Berkeley
    • Physics, UC Berkeley
    • Physics Department, UC Berkeley and Lawrence Berkeley National Lab
    • Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory
    • Department of Physics, University of California, Berkeley
    • Physics Department, University of California Berkeley and Lawrence Berkeley National Lab
    • Department of physics, University of California - Berkeley
    • Lawrence Berkeley National Lab and University of California - Berkeley
    • Materials Sciences Division, Lawrence Berkeley National Laboratory & Department of Physics, University of California at Berkeley
    • UC Berkeley and Lawrence Berkeley National Lab
    • Physics, University of California - Berkeley

  • Jack Deslippe

    • Lawrence Berkeley Natl Lab
    • Lawrence Berkeley National Laboratory
    • NERSC, Lawrence Berkeley National Laboratory