etmc/tmLQCD — pull request #212 by urbach (2013-01-11 13:30:27+00:00)
Title: Rational HMC monomial for non-degenerate twisted mass doublet

This is an implementation of a RHMC monomial for the non-degenerate twisted mass doublet. Its not yet to pull in, but I opened this pull request rather for discussion. The new input monomial is

BeginMonomial NDRAT
Timescale = 1
kappa = 0.170
AcceptancePrecision = 1e-20
ForcePrecision = 1e-12
StildeMin = 0.013577
StildeMax = 3.096935
Name = ndrat
DegreeOfRational = 12
Cmin = 0
Cmax = 11
ComputeEVFreq = 1
2KappaEpsBar = 0.0935
2Kappamubar = 0.1105
EndMonomial

`Cmin` and `Cmax` is the range of terms in the rational to be included in this monomial. This allows frequency splitting by distributing the same rational approxmiation over many timescales. `StildeMin` (`StildeMax`) is the minimal (maximal) eigenvalue of the squared even/odd preconditioned nd twisted Dirac operator. (see the documentation for details)

Heatbath and acceptance steps are checked and working. The derivative doesn't work yet, so any hint would be welcome...