# [Users] bug or feature?

Comer Duncan comer.duncan at gmail.com
Thu Sep 10 08:17:00 CDT 2015

Hi Eloisa,

On the question of the Robin boundary condition on \psi, I definitely know
I need it for the initial data. For subsequent evolution using McLachlan, I
am not so sure.  Is that outer bc used by ET users?

Also, note that I am trying to get Robin used since the mass is not
knowable until the converged \psi is determined by solving the Ham
constraint.  So, please let me know what is existing practice with
McLachlan.

Comer

On Thu, Sep 10, 2015 at 7:12 AM, Eloisa Bentivegna <
eloisa.bentivegna at ct.infn.it> wrote:

> On 09/09/15 22:36, Comer Duncan wrote:
> > Hi,
> >
> > I was able to get ET to build with the Brill example.  However, after
> > constructing a par file (attached) I have found that the execution
> > crashes.  The main complaint seems to be that there are not enough
> > prolongation levels associated with the grid functions. One is assigned
> > and Carpet seems to say it needs at least 2. I am attaching the .err
> > file (short) so you'll get a hint of what I see.  I can perhaps post the
> > .out file to pastebin if that would help.   Indeed all time levels for
> > the grid functions is set to 1. What could be responsible?  Am I missing
> > something in the par file or is there something in the generated code
> > which needs tweaking? Also, the CT method I use needs the Robin outer
> > bc, which is set in the par file.  More needed?
>
> Hi Comer!
>
> I think you forgot to attach the .err file... which grid functions are
> affected by the prolongation error?
>
> Also, do you need the Robin BCs for the initial data only, or during the
> evolution too?
>
> Eloisa
>
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