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1 files changed, 34 insertions, 30 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex index 84d25c6..8d682fe 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -197,41 +197,45 @@ about per-point status codes between the global and the local interpolator %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -\section{\InterpGridArrays\ Return Codes} +\subsection{\InterpGridArrays\ Return Codes} \label{PUGHInterp_return_codes} -In the single-processor case the return code of \InterpGridArrays will be set -to the return code of \verb|CCTK_InterpLocalUniform()|. - -In the multi-processor case, an error condition occuring only locally on a -processor ({\tt CCTK\_\-ERROR\_\-INTERP\_\-POINT\_OUTSIDE} for points which -could not be mapped onto any processor, {\tt CCTK\_\-ERROR\_\-INTERP\_\-% -GHOST\_SIZE\_\-TOO\_SMALL} if -the size of the ghostzones is too small for the given local local interpolator, -or any error codes returned by \verb|CCTK_InterpLocalUniform()| for the query -call) will cause all processors to return immediately from the collective call -to {\tt CCTK\_InterpGridArrays()} with that 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 interpolation status (coded in the return value -of {\tt CCTK\_InterpGridArrays()}), a local interpolation status code will be -stored in the user-supplied parameter table (if given) as +The return code from \InterpGridArrays%%% +\footnote{%%% + In C the return code is the \InterpGridArrays\ + function result; in Fortran it's returned through + the first ({\tt status}) argument.%%% + }%%% +is determined as follows: +\begin{itemize} +\item If any of the arguments are invalid (e.g. $\verb|N_dims| < 0$), + the return code is \verb|UTIL_ERROR_BAD_INPUT|. +\item If any errors are encountered when processing the + parameter table, the return code is the + appropriate \verb|UTIL_ERROR_TABLE_*| error code. +\item If the query call determines that + the number of ghost zones in the grid is too small + for the local interpolator, the return code is + \verb|CCTK_ERROR_INTERP_POINT_OUTSIDE|. +\item Otherwise, the return code from \InterpGridArrays\ is + the minimum over all processors of the return code + from the local interpolation on that processor. +\end{itemize} + +If the local interpolator supports per-point status returns +and the user supplies an interpolator parameter table, +then in addition to this global interpolation return code, +\InterpGridArrays\ also returns a ``local'' status code which +describes the outcome of the local interpolation for all the +interpolation points which originated on {\em this\/} processor: \begin{verbatim} CCTK_INT local_interpolator_status; \end{verbatim} -Depending on whether the local interpolator does provide such status information -about the interpolation result at individual points, this local interpolation -status code will be determined as the overall minimum of the status -values for all the points a processor had requested for the interpolation -(for this purpose, the table options \verb|per_point_status| and \verb|error_point_status| are used to pass per-point status values between the local and the -global interpolator). - -If the local interpolator does not support the feature of providing -per-point status information, the local interpolation status code will be set -to the return code of \verb|CCTK_InterpLocalUniform()| on that processor. +This gives the minimum over all the interpolation points originating +on {\em this\/} processor, of the \verb|CCTK_InterpLocalUniform()| +return codes for those points. (It doesn't matter on which processor(s) +the points were actually interpolated -- \InterpGridArrays\ takes care +of gathering all the status information back to the originating processors.) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |