[Developers] [Patches] Storing gauge time derivatives in ADMBase

[Erik Schnetter]

On Apr 9, 2008, at 23:33:08, Erik Schnetter wrote:
> The ADMBase variables store currently the 3-metric, lapse, shift,  
> and extrinsic curvature.  They do not store the time derivatives of  
> lapse and shift, which makes it impossible to calculate the time  
> derivative of the 4-metric from the ADMBase variables.  This is a  
> shortcoming, since almost all current evolution systems require  
> these, including common BSSN gauge conditions and harmonic evolution  
> schemes.  (In many cases, initial data assume that these additional  
> time derivatives are zero to get around this issue.)
>
> The enclosed patch adds grid functions for dtlapse and dtbetax,  
> dtbetay, and dtbetaz.  It also adds a few state variables so that  
> codes can determine whether these variables have storage; storage is  
> off by default for backwards compatibility.  This is similar to the  
> shift vector, which also has no storage by default.


I have applied this patch.

-erik

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Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/

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