The Exact One Flavor Algorithm (EOFA)

The Exact One Flavor Algorithm (EOFA) for Mobius domain wall fermion eliminates the need to perform the rational approximations for single flavor fermion (currently strange and charm quark) determinant during the molecular dynamics (MD) hybrid monte carlo (HMC). In QUDA the EOFA dslash is implemented for Mobius domain wall that has constant and real fifth dimension coefficients (b's and c's). The convention follows [arXiv:1706.05843].

The five EOFA specific parameters are the three additional masses(mq1, mq2, mq3), plus/minus (eofa_pm), and the shift (eofa_shift).

It can be tested with

tests/dslash_test \
  --matpc even-even \
  --dim 12 12 12 16 \
  --Lsdim 12 \
  --gridsize 1 1 1 1 \
  --dslash-type mobius-eofa \
  --b5 2.5 --c5 1.5 \
  --prec double \
  --test MatPCDagMatPC(for example)

When using the EOFA dslash, in additional to the usual Mobius parameters these need to be set

  inv_param.dslash_type   = QUDA_MOBIUS_DWF_EOFA_DSLASH;

  inv_param.mq1           = mass;
  inv_param.mq2           = mq2;
  inv_param.mq3           = mq3;
  inv_param.eofa_shift    = eofa_shift;
  inv_param.eofa_pm       = eofa_pm;