This was something I stumbled on when trying to test CCE with the development version of ET. There were nans in the output files for particular observer radii, and only at early times.

On 05/16/2012 05:09 PM, Einstein Toolkit wrote:

#905: NaNs in ADMBase::gxx using Development Version of ET ---------------------------------+------------------------------------------ Reporter: yosef@… | Type: defect Status: new | Priority: major Milestone: | Component: Other Version: | Keywords: ---------------------------------+------------------------------------------ While testing the CCE in the ET, I stumbled across an issue interpolating the admbase::metric at CCTK_POSTSTEP in GLOBAL mode at particular spatial points.

The "bug" (or parfile/scheduling error) seems to be sensitive to the exact grid setup. Basically, when I use the qc0-mclachlan-CCE_Cauchy.par parfile, I get nans for gxx. I made a small test thorn that only interpolates gxx at a particular point. Nans show up at iteration 1.

attached is the parfile I used and the test thorn.

Here is the output from the above test thorn: gxx(3.966899,0.000000,-17.630662) = 1.1160523626974641 at iter 0 on proc 1 gxx(3.966899,0.000000,-17.630662) = 1.1160523626974641 at iter 0 on proc 0 gxx(3.966899,0.000000,-17.630662) = -nan at iter 8 on proc 1 gxx(3.966899,0.000000,-17.630662) = -nan at iter 8 on proc 0 gxx(3.966899,0.000000,-17.630662) = -nan at iter 16 on proc 1 gxx(3.966899,0.000000,-17.630662) = -nan at iter 16 on proc 0

etc....