Hi,
A bit more information to add to the confusion. Using the git version of Carpet, I was not able to get the same results on 1 and 2 processors. Not even going to a full grid as Erik did. However, with the added interpolation debug output built into AHFinderDirect I do notice a somwehat different behavior. With PUGH I see differences (within 11-12 decimal places) in the interpolation results before the first call to the linear solver. With Carpet I don't. There the first differences appear in the horizon coordinates after the first linear solve. So with Carpet it appears that the linear solver gets the same data on 1 and 2 procs but finds a different solution.
I get the same results using PUGH and Carpet on 1 processor. The results on 2 processors using PUGH and Carpet differs from the 1 processor results and with each other.
Also the results differ depending on whether bitant or full mode is used even on 1 processor.
Cheers,
Peter
On Mon, 8 Nov 2010, Erik Schnetter wrote:
On Mon, Nov 8, 2010 at 12:07 PM, Eloisa Bentivegna bentivegna@cct.lsu.edu wrote: On Nov 8, 2010, at 5:58 PM, Erik Schnetter wrote:
> I tested further, using Carpet instead of PUGH. I believe that the problem is in the single processor case of PUGHInterp, i.e. that the 2 process results are actually correct. Carpet gives identical answers for 1 and 2 processes.Interesting, we concurrently did the same test, but I still did get differences. Can you send me your parameter file?
I used the Mercurial version of Carpet, and I disabled bitant mode. I attach my parameter file.
-erik
-- Erik Schnetter schnetter@cct.lsu.edu http://www.cct.lsu.edu/~eschnett/