GPU acceleration of collinear and noncollinear DFT using a numerical atomic orbital-based DFT code

Kawai, Hiroyuki*; Sekikawa, Takuya; Ozaki, Taisuke*; Ono, Yoshiaki*

OpenMX, a first-principles electronic structure calculation software, is a computational code based on density functional theory primarily used to determine the stable structure and electronic states of materials. This study attempted to develop a method for accelerating calculations using OpenMX by employing a GPU, Graphics Processing Unit, typically used for image processing. Test calculations on a 512-atom diamond structure silicon system achieved approximately double the speed compared to CPU-based calculations. Furthermore, for noncollinear calculations used in magnetic structure calculations, a 384-atom silicon system achieved 2.6 times faster speed than the CPU. Especially, GPU acceleration for noncollinear calculations is unprecedented. The results obtained in this study enable the handling of larger systems than previously possible in first-principles electronic structure calculations.