Document the error code handling for processor-local error conditions.

git-svn-id: http://svn.cactuscode.org/arrangements/CactusPUGH/PUGHInterp/trunk@59 1c20744c-e24a-42ec-9533-f5004cb800e5

1 files changed, 12 insertions, 0 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 2ec0cd2..74b5a5c 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -180,6 +180,18 @@ implemented. Instead, if any point cannot be mapped onto a processor
 (i.e.\  the point is outside the global grid) the error code
 \verb|CCTK_ERROR_INTERP_POINT_OUTSIDE| is returned.
 
+An error condition occuring only locally on a processor
+(\verb|CCTK_ERROR_INTERP_POINT_OUTSIDE| or error codes returned by
+\verb|CCTK_InterpLocalUniform()|) will cause all processors to return from the
+collective call to {\tt CCTK\_InterpGridArrays()} with an error code.
+If a local error occured on more than one processor, the actual global error
+code returned by all processors is implementation-dependent: for
+{\tt PUGHInterp} it will be the error code from the processor with the lowest
+processor ID.
+In addition to this global error code (coded in the return value
+of {\tt CCTK\_InterpGridArrays()}), the local interpolation status is stored
+in the parameter table (if given) as an integer scalar value with the option
+key "local_interpolator_status".
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 \section{\PUGHInterp\ and the old Cactus Interpolation API}