[Users] [Commits] [svn:einsteintoolkit] Paper_EinsteinToolkit_2010/examples/bbh/ (Rev. 85)

Bruno Coutinho Mundim bcmsma at astro.rit.edu
Wed May 11 17:39:41 CDT 2011

Hi Erik,

I have attached the schedule output for this run. I suspect CarpetReduce
is somehow overwriting the weight function set by CarpetMask.


Erik Schnetter wrote:
> That is strange. I assume some other routine overwrites it. Can you
> check the schedule? Is there another CarpetMask or CarpetReduce
> routine acting on the mask afterwards?
> -erik
> On Wed, May 11, 2011 at 1:30 PM, Bruno C. Mundim <bcmsma at astro.rit.edu> wrote:
>> Thanks, Erik! On a related note: I checked if CarpetMask was setting
>> weight[ind]=0 inside the horizons and it seems to do so correctly.
>> However CarpetReduce::weight still do not reflect that. Its output
>> still doesn't have the horizons masked out.
>> Thanks,
>> Bruno.
>> Erik Schnetter wrote:
>>> On Wed, May 11, 2011 at 12:53 PM, Bruno C. Mundim <bcmsma at astro.rit.edu>
>>> wrote:
>>>> Hi Roland:
>>>> Roland Haas wrote:
>>>>> Hello Bruno,
>>>>>>  a) Its evolution is stopped with Nans around 8.6M. Nans appear to come
>>>>>>  from the BSSN fields, but still needs further investigation.
>>>>> Hmm I could evolve the qc0 example in McLachlan. Maybe there are
>>>>> differences in the parameter file that make the error "obvious".
>>>> A few obvious changes that I can think of:
>>>> 1) I reduced the number of spherical surfaces from 5 to 3. Now the
>>>> puncture tracker uses surfaces 0 and 1, AHFinderDirect track those
>>>> surfaces and load AH related info there. QLM, CarpetTracker and
>>>> CarpetMask uses those 2 surfaces then. I will go back to 5 surfaces
>>>> as it was set before. Maybe I am missing some subtle scheduling order
>>>> here. I don't know.
>>>> 2) I added a few general parameters I am used to use to CarpetInterp,
>>>> CarpetLib and CarpetRegrid2.
>>>> 3) From a discussion I had with Peter on the ET workshop, I decided
>>>> to change the AHFinderDirect interpolator to Hermite.
>>>> So I will switch back to what it was and avoid to do so many changes
>>>> at once! :) However I find strange that these changes could be the
>>>> cause of what I am seeing.
>>>>>>  c) When CarpetReduce::weight is output, its values seem strange to me.
>>>>>>  Most of the domain has 1/2 set. A few points close to the boundary 1/4
>>>>>>  and the boundaries 0 (physical and ghost). No mask out values inside
>>>>>>  AH is shown, ie they still are set to 1/2. These values seem to make
>>>>>>  more sense to AMR restriction operations.
>>>>> Are you maybe looking at the z=0 plane? That plane has a weight of 1/2
>>>>> since only half of the volume of each cell is used when eg. computing
>>>>> the simulation volume. I have never used CarpetMask myself (but have
>>>>> written a similar thorn of my own... would have paid to look into Carpet
>>>>> first I guess :-) )
>>>> Yes I was looking at the z=0 plane and had refection symmetry set up!
>>>> Thanks for pointing this out. If we go out of the plane then the
>>>> weight=1.0 values show up. A more careful look into the data, I noticed
>>>> the zeros are set in the buffer zones indeed with the exception of the
>>>> third point (ghostzone=3) in the domain (from the AMR boundary) that has
>>>> its value set to 1/4. Do you know why?
>>> For some reason that I currently cannot recall, the ghost zones in the
>>> mask may be set to 1 instead of 0. However, ghost zones are ignored
>>> anyway by a different mechanism when reducing (by using cctk_bbox and
>>> cctk_nghostzones).
>>> The particular values indicate how much of the "control cell"
>>> surrounding this grid point should be taken into account when
>>> reducing. If the value is 1/4, then you may be looking at an edge
>>> point (e.g. and x-y edge in the z=0 plane), where 3/4 of the control
>>> cell are already covered by the corresponding coarse grid.
>>> One important test is that the sum of all weights times the grid cell
>>> volume equals the total volume of the simulation domain. If you look
>>> into the simulation log output and search for "volume" there, you
>>> should find a corresponding statement.
>>> -erik

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: schedule
Url: http://lists.einsteintoolkit.org/pipermail/users/attachments/20110511/cdf51f67/attachment-0001.pl 

More information about the Users mailing list