24 research outputs found
New Multithreaded Hybrid CPU/GPU Approach to HartreeâFock
In this article, a new multithreaded HartreeâFock CPU/GPU method is presented which utilizes automatically generated code and modern C++ techniques to achieve a significant improvement in memory usage and computer time. In particular, the newly implemented Rys Quadrature and Fock Matrix algorithms, implemented as a stand-alone C++ library, with C and Fortran bindings, provides up to 40% improvement over the traditional Fortran Rys Quadrature. The C++ GPU HF code provides approximately a factor of 17.5 improvement over the corresponding C++ CPU code
Distributed Memory, GPU Accelerated Fock Construction for Hybrid, Gaussian Basis Density Functional Theory
With the growing reliance of modern supercomputers on accelerator-based
architectures such a GPUs, the development and optimization of electronic
structure methods to exploit these massively parallel resources has become a
recent priority. While significant strides have been made in the development of
GPU accelerated, distributed memory algorithms for many-body (e.g.
coupled-cluster) and spectral single-body (e.g. planewave, real-space and
finite-element density functional theory [DFT]), the vast majority of
GPU-accelerated Gaussian atomic orbital methods have focused on shared memory
systems with only a handful of examples pursuing massive parallelism on
distributed memory GPU architectures. In the present work, we present a set of
distributed memory algorithms for the evaluation of the Coulomb and
exact-exchange matrices for hybrid Kohn-Sham DFT with Gaussian basis sets via
direct density-fitted (DF-J-Engine) and seminumerical (sn-K) methods,
respectively. The absolute performance and strong scalability of the developed
methods are demonstrated on systems ranging from a few hundred to over one
thousand atoms using up to 128 NVIDIA A100 GPUs on the Perlmutter
supercomputer.Comment: 45 pages, 9 figure
Computational Physics on Graphics Processing Units
The use of graphics processing units for scientific computations is an
emerging strategy that can significantly speed up various different algorithms.
In this review, we discuss advances made in the field of computational physics,
focusing on classical molecular dynamics, and on quantum simulations for
electronic structure calculations using the density functional theory, wave
function techniques, and quantum field theory.Comment: Proceedings of the 11th International Conference, PARA 2012,
Helsinki, Finland, June 10-13, 201
The grid-based fast multipole method - a massively parallel numerical scheme for calculating two-electron interaction energies
Algorithms and working expressions for a grid-based fast multipole method (GB-FMM) have been developed and implemented. The computational domain is divided into cubic subdomains, organized in a hierarchical tree. The contribution to the electrostatic interaction energies from pairs of neighboring subdomains is computed using numerical integration, whereas the contributions from further apart subdomains are obtained using multipole expansions. The multipole moments of the subdomains are obtained by numerical integration. Linear scaling is achieved by translating and summing the multipoles according to the tree structure, such that each subdomain interacts with a number of subdomains that are almost independent of the size of the system. To compute electrostatic interaction energies of neighboring subdomains, we employ an algorithm which performs efficiently on general purpose graphics processing units (GPGPU). Calculations using one CPU for the FMM part and 20 GPGPUs consisting of tens of thousands of execution threads for the numerical integration algorithm show the scalability and parallel performance of the scheme. For calculations on systems consisting of Gaussian functions (alpha = 1) distributed as fullerenes from C-20 to C-720, the total computation time and relative accuracy (ppb) are independent of the system size.Peer reviewe
Excited-State Electronic Structure with Configuration Interaction Singles and TammâDancoff Time-Dependent Density Functional Theory on Graphical Processing Units
Excited-state calculations are implemented in a development version of the GPU-based TeraChem software package using the configuration interaction singles (CIS) and adiabatic linear response TammâDancoff time-dependent density functional theory (TDA-TDDFT) methods. The speedup of the CIS and TDDFT methods using GPU-based electron repulsion integrals and density functional quadrature integration allows full ab initio excited-state calculations on molecules of unprecedented size. CIS/6-31G and TD-BLYP/6-31G benchmark timings are presented for a range of systems, including four generations of oligothiophene dendrimers, photoactive yellow protein (PYP), and the PYP chromophore solvated with 900 quantum mechanical water molecules. The effects of double and single precision integration are discussed, and mixed precision GPU integration is shown to give extremely good numerical accuracy for both CIS and TDDFT excitation energies (excitation energies within 0.0005 eV of extended double precision CPU results)