A number of stochastic methods developed for the calculation of fermion loops are investigated and compared, in particular with respect to their efficiency when implemented on Graphics Processing Units (GPUs). We assess the performance of the various methods by studying the convergence and statistical accuracy obtained for observables that require a large number of stochastic noise vectors, such as the isoscalar nucleon axial charge. The various methods are also examined for the evaluation of sigma-terms where noise reduction techniques specific to the twisted mass formulation can be utilized thus reducing the required number of stochastic noise vectors.
@article{arxiv.1309.2256,
title = {Evaluation of disconnected quark loops for hadron structure using GPUs},
author = {C. Alexandrou and M. Constantinou and V. Drach and K. Hadjiyiannakou and K. Jansen and G. Koutsou and A. Strelchenko and A. Vaquero},
journal= {arXiv preprint arXiv:1309.2256},
year = {2015}
}
Comments
Manuscript expanded with two additional figures and an appendix. Version accepted for publication in Comp. Phys. Commun. 16 pages, 15 Figures