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.



git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/Multipole/trunk@68 4f5cb9a8-4dd8-4c2d-9bbd-173fa4467843

1 files changed, 7 insertions, 1 deletions

diff --git a/param.ccl b/param.ccl
index 7ba4c91..2d192ff 100644
--- a/param.ccl
+++ b/param.ccl
@@ -10,7 +10,13 @@ CCTK_STRING interpolator_name "Which interpolator should I use"
 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?"
 {