Recipes for eccentricity reduction of DNS data with Sgrid and BAM or Cactus

There are 2 ways to reduce eccentricity:

1. Run sgrid with:

DNSdata_adjust = forcebalance always

With this sgrid adjusts DNSdata_Omega at every iteration using the force balance equation. In this case we need the script EccRed.py

2. Run sgrid with:

DNSdata_adjust = Py0

With this sgrid keeps DNSdata_Omega fixed to whatever we specify in its parfile. In this case we need the script EccRed_noForceBal.py

Explanation:

The 2nd way is recommended for low eccentricities unless the mass ratio is high. The 2nd way is described in EccRed_v2.md

Additional details about the 2 ways are in Ecc-Red-Notes.txt. For either way we need scripts to fit the orbital separation to the sinusoidal curve d(t) = S0 + A0 t + 0.5 A1 t^2 - (B/omega) cos(omega t + phi).

For the 1st way we have EccRed.py (see e-based eccentricity reduction in 1507.07100). For the 2nd way we use EccRed_noForceBal.py (see Omega-based eccentricity reduction in 1910.09690).

To check that the fit was successful, one needs to plot the fit and the original data. This can be done with tgraph.