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diff --git a/doc/documentation.tex b/doc/documentation.tex index 1f27685..020e6c3 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -603,6 +603,33 @@ periodicity, staggered boundary & no & yes & 0 For other boundary conditions such as Dirichlet or Robin, one can choose these parameters freely. +\section{Querying about boundary points} +\label{CactusBase:CoordBase:boundary-query} + +When iterating over grid points, one usually needs to know about the +boundary sizes and boundary types present. One convenient way is +provided by the aliased function \texttt{GetBoundarySizesAndTypes}: +\begin{verbatim} +CCTK_INT FUNCTION GetBoundarySizesAndTypes + (CCTK_POINTER_TO_CONST IN cctkGH, + CCTK_INT IN size, + CCTK_INT OUT ARRAY bndsize, + CCTK_INT OUT ARRAY is_ghostbnd, + CCTK_INT OUT ARRAY is_symbnd, + CCTK_INT OUT ARRAY is_physbnd) +\end{verbatim} +The input argument \texttt{size} describes the size of the four output +arrays as allocated by the caller, and should be \texttt{2*cctk\_dim}. +The output of this routine describes, for each of the faces of the +domain: +\begin{description} +\item[\texttt{bndsize}] The number of boundary points +\item[\texttt{is\_ghostbnd}] Whether this face is a ghost + (inter-process) boundary +\item[\texttt{is\_symbnd}] Whether this face is a symmetry boundary +\item[\texttt{is\_physbnd}] Whether this face is a physical boundary +\end{description} + \section{Driver Issues} When using the CoordBase domain and boundary parameters, the driver |