  The MuST package is a computational software designed for ab initio
electronic structure calculations for solids. The Locally Self-consistent
Multiple Scattering (LSMS) method implemented in MuST allows to perform the
electronic structure calculation for systems with a large number of atoms per
unit cell. For the LSMS method with muffin-tin potential approximation, the
major computational challenge is the matrix inverse for the scattering matrix
calculation, which could take more than 90\% of the computing time. However,
the matrix inverse can be significantly accelerated by modern
graphical-processing-units (GPUs). In this paper, we discuss our approach to
the code acceleration by offloading the matrix inverse tasks to the GPUs
through a Fortran-C interface from the Fortran code to the CUDA code. We report
our performance results showing significant speedup ratio achieved to the
calculations of NiAu alloy, a candidate for thermoelectric materials.
