  We derived explicit expressions of symmetry operators on Wannier basis, and
implemented these operators in WannSymm software. Based on this implementation,
WannSymm can i) symmetrize the real-space Hamiltonian output from Wannier90
code, ii) generate symmetry operators of the little group at a specific
k-point, and iii) perform symmetry analysis for Wannier band structure. In
general, symmetrized Hamiltonians yield improved results compared with the
original ones when they are employed for nodal structure searching, surface
Green's function calculations, and other model calculations.
