[Users] McLachlan BSSN

[Peter Diener]

Hi all,

On Tue, 29 Jan 2013, Erik Schnetter wrote:

> Please keep all discussion on the McLachlan BSSN code on this mailing list.
> This ensures that everybody knows about everything that is going on, and
> avoid duplicate work.
> 
> At the moment, we seem to have approximately three different versions of the
> BSSN code that seem to be incompatible:
> - the (official) trunk version
> - a version (potentially faster and more accurate) by Jim van Meter
> - a more flexible version (regarding gauge conditions) by Peter Diener
> 
> I would suggest that we discuss things on this list before we proceed.
> 
> John, Peter, could you describe your changes here?

Sure. In response to a long standing ticket #590, I split the gauge
evolution routines out from the main RHS routines, in order to be able
to schedule gauge evolution routines conditionally on the values of
lapse_evolution_method and shift_evolution_method instead of 
unconditionally always evolve the gauges.  This should allow us to evolve
spacetimes with static gauges or gauges set by other thorns (for example 
EinsteinExact). It also makes it easier to add new gauge evolution 
routines to McLachlan and have the code be more readable. In the process I 
also moved the advection terms into the new gauge evolution routines since 
these should only be added if McLachlan is actually evolving the gauge. 
The dissipation routine was handled similarly.

Cheers,

   Peter

> -erik
> 
> --
> Erik Schnetter <schnetter at cct.lsu.edu>
> http://www.perimeterinstitute.ca/personal/eschnetter/
> 
>