Comparing iterative methods for overlap and twisted mass fermions
  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. 
T. Chiarappa, K. Jansen, K.-I. Nagai, M. Papinutto, L. Scorzato, A.   Shindler, C. Urbach, U. Wenger, I. Wetzorke