Roland
This is almost possible. For puncture data, one typically evolves lapse, shift, and a quantity B (the time derivative of the shift). For Kerr-Schild data, one also needs to evolve A, the time derivative of the lapse. Otherwise, Kerr-Schild data are not stationary. (One could instead add an offset alpha_0 to the evolution equations for K, but that is quite non-standard and not implemented in McLachlan.)
Additionally, I find it convenient to smooth all quantities near the singularity, and to choose to advect both lapse and shift. I don't know whether the latter is necessary in theory, but I am always using it.
I can send a sample parameter file if that helps.
-erik
On Thu, Apr 25, 2019 at 10:38 AM Haas, Roland rhaas@illinois.edu wrote:
Hello all,
I am wondering if it is possible to take initial data for a single (maybe spinning) black whole in Kerr-Schild coordinates as provided by Exact or EinsteinExact (metric, curvature, lapse, shift, time derivatives of lapse and shift) and chose parameters for the "usual" 1+log and Gamma driver gauge evolution conditions so that this data is a stationary solution of the evolution equations?
Yours, Roland
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