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.

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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