The numerical evaluation of Slater integrals on graphics processing units

Abstract

This article presents SlaterGPU, a graphics processing unit (GPU) accelerated library that uses OpenACC to numerically compute Slater- type orbital (STO) integrals. The electron repulsion integrals (ERI) are computed under the RI approximation using the Coulomb potential of the Slater basis function. To fully realize the performance capabilities of modern GPUs, the Slater integrals are evaluated in mixed- precision, resulting in speedups for the ERIs of over 80à . Parallelization on multiple GPUs allows for integral throughput of over 3 million integrals per second. This places STO integral throughput within reach of single- threaded, conventional Gaussian integration schemes. To test the quality of the integrals, the fluorine exchange reaction barrier in fluoromethane was computed using heat- bath configuration interaction (HBCI). In addition, the singlet- triplet gap of cyclobutadiene was examined using HBCI in a triple- ζ, polarized basis set. These benchmarks demonstrate the library’s ability to generate the full set of integrals necessary for configuration interaction with up to 6h functions in the auxiliary basis.SlaterGPU, a GPU accelerated library for numerically computing Slater- type orbital (STO) integrals, is presented in this study. The library achieves speedups over CPU for the electron repulsion integrals of over 80à . By utilizing mixed- precision arithmetic and multi- GPU parallelism, SlaterGPU achieves STO integral throughput of over 3 million integrals per second. SlaterGPU also generates the full complement of electron integrals needed for methods such as full configuration interaction.