Comparing iterative methods for overlap and twisted mass fermions

TL;DR

This paper systematically compares iterative methods for computing fermion propagators using overlap and twisted mass fermions, revealing that overlap methods are significantly more computationally expensive, and evaluates algorithms for topological index calculation.

Contribution

It provides a detailed comparison of iterative algorithms for overlap and twisted mass fermions, highlighting efficiency differences and optimal methods for topological index computation.

Findings

Overlap fermion calculations are 20-40 times more expensive than twisted mass.

Best algorithms identified for each fermion type improve computational efficiency.

Efficiency of topological index calculation methods for overlap fermions is evaluated.

Abstract

We present a systematic comparison of various iterative methods to obtain the fermion propagator with both overlap and twisted mass fermions at fixed pion mass in the quenched approximation. Taking the best available algorithm in each case we find that calculations with the overlap operator are by a factor of 20-40 more expensive than with the twisted mass operator at the parameter values considered here. For the overlap operator we also compare the efficiency of various methods for calculating the topological index.