User: hinder Date: 2010/11/15 02:42 PM
Modified: /trunk/ param.ccl
Log: Change default interpolator parameters to disable off-centering of stencil
AEILocalInterp by default will off-centre the interpolation stencil if there are insufficient points to perform the interpolation. In a parallel setting, this could happen due to there being insufficient ghost points for the interpolator chosen. The off-centering leads to an interpolation error which is of the correct order but larger than for a centered stencil. More importantly, it leads to different results on different numbers of processes. With this commit, Multipole will (by default) disable off-centering in the interpolator.
File Changes:
Directory: /trunk/ ==================
File [modified]: param.ccl Delta lines: +7 -1 =================================================================== --- trunk/param.ccl 2010-11-04 16:42:55 UTC (rev 67) +++ trunk/param.ccl 2010-11-15 20:42:48 UTC (rev 68) @@ -10,8 +10,14 @@ CCTK_STRING interpolator_pars "Parameters for the interpolator" { ".*" :: "Any string that Util_TableSetFromString() will take" -} "order=3" +} "order=3 boundary_off_centering_tolerance={0.0 0.0 0.0 0.0 0.0 0.0} boundary_extrapolation_tolerance={0.0 0.0 0.0 0.0 0.0 0.0}"
+# The above makes sure that the interpolator doesn't off-centre the +# interpolation stencil if there are insufficient points to +# interpolate, which can happen if there are insufficient ghost-zones +# for the interpolation method used, and can lead to processor-number +# dependent results. + CCTK_STRING coord_system "What is the coord system?" { ".*" :: "Any smart string will do"