Shifted unitary orthogonal methods for the overlap inversion

Abstract

In this work we compare the convergence of the shifted unitary orthogonal method (SUOM) and different Krylov subspace solvers for propagator computations with overlap fermions. We show that the SUOM algorithm performs similarly to the shifted unitary minimal residual method (SUMR) with the latter converging slightly faster. When the geometric optimality is applied to SUOM we get e new algorithm which is faster than SUMR.