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Diffstat (limited to 'doc/documentation.tex')
| -rw-r--r-- | doc/documentation.tex | 71 |
1 files changed, 28 insertions, 43 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex index 61fe9fd..686ed86 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -51,7 +51,7 @@ The `cartoon' method was first implemented in Cactus3 by Steve Brandt and Bernd Br\"ugmann, and was translated to Cactus4 by Sai Iyer. Details of the method can be found in \cite{Alcubierre-etal-2001}. This document provides a practical guide -to using the code as it is currently implemented. +to using the thorn as it is currently implemented. \section{Basic usage} @@ -86,18 +86,17 @@ Only a small number of parameters need to be set to use For example, the following is a section of a parameter file which sets up a cartoon-style grid in bitant mode. - \begin{verbatim} -activethorns = "cartoon2d" +activethorns = "cartoon2d cartgrid3d pugh" -cartoon2d::cartoon_active = "yes" -cartoon2d::order = 3 -cartoon2d::allow_grid_resize = "yes" +cartoon2d::cartoon_active = "yes" +cartoon2d::order = 3 +cartoon2d::allow_grid_resize = "yes" grid::type = "byspacing" -grid::domain = "bitant" -grid::bitant_plane = "xy" +grid::domain = "bitant" +grid::bitant_plane = "xy" grid::dxyz = 0.2 driver::global_nx = 16 @@ -108,17 +107,15 @@ driver::ghost_size_x = 2 driver::ghost_size_y = 1 driver::ghost_size_z = 2 -driver::processor_topology = "manual" -driver::processor_topology_3d_x = 1 -driver::processor_topology_3d_y = 1 -driver::processor_topology_3d_z = 2 +driver::processor_topology = "manual" +driver::processor_topology_3d_x = 1 +driver::processor_topology_3d_y = 1 +driver::processor_topology_3d_z = 2 -grid::avoid_originy = "yes" +grid::avoid_originy = "no" \end{verbatim} - -The following features are of note: - +The following features are worth noting: \begin{itemize} \item The \texttt{order} parameter specifies that 3rd order @@ -136,25 +133,22 @@ The following features are of note: that only the positive $z$-axis is evolved and a reflection boundary is imposed along $z=0$. - \item It is not necessary, but often helpful, to specify the + \item Though not necessary, it is often helpful to specify the processor topology explicitly to ensure that that only one processor is allocated to the $y$ direction, and that the processors in the $x$ and $z$ directions reflect the relative lengths of these axes (though in this example it doesn't matter which of these axes gets two processors). - \item The \texttt{avoid\_originy} parameter needs to be set so that - the cartoon plane corresponds to $y=0$. + \item The \texttt{avoid\_originy} parameter needs to be turned off + so that the cartoon plane corresponds to $y=0$. \end{itemize} - Also, it is important to keep in mind that other thorns may also require their own parameters to be set in order to interact -appropriately with \texttt{Cartoon2D}. For instance, see -Section \ref{sec:interaction}. - -Working parameter files can be found in the \texttt{Cartoon2D/test/} -directory. +appropriately with \texttt{Cartoon2D}. For instance, see Section +\ref{sec:interaction}. Examples of working parameter files can be +found in the \texttt{Cartoon2D/test/} directory. \begin{figure} \centering @@ -190,8 +184,8 @@ centred in each grid direction. One way to get around this is to specify the grid \texttt{byrange}, giving minimum and maximum coordinate values for each axis so that the $(dx,dy,dz)$ values are determined by dividing the range by the number -of grid points. In this it can, however, be quite complicated to -ensure that the grid spacing is even in each direction and that an +of grid points. However, using this method it can be quite complicated +to ensure that the grid spacing is even in each direction and that an appropriate number of ghost points extend past the $z$ axis. A simple hack to get around this complication is to specify the grid @@ -220,24 +214,18 @@ In practice, however, to avoid dependencies on \texttt{Cartoon2D}, it is often the case that the source code for such thorns make use of \texttt{\#ifdef} statements to check whether \texttt{Cartoon2D} has been compiled in. Then, to check whether a cartoon grid is active, -other thorn-specific parameters need to be set. - -For instance, if the \texttt{ADM\_BSSN} thorn is being used for -evolution, then the parameter - +other thorn-specific parameters need to be set. For instance, if the +\texttt{ADM\_BSSN} thorn is being used for evolution, then the +parameter \begin{verbatim} adm_bssn::cartoon = "yes" \end{verbatim} - must be set. Similarly, the \texttt{ADM} evolution system requires -\texttt{adm::cartoon} to be set. - -The \texttt{AHFinder} thorn requires that the parameter - +\texttt{adm::cartoon} to be set. The \texttt{AHFinder} thorn requires +that the parameter \begin{verbatim} ahfinder::ahf_cartoon = "yes" \end{verbatim} - be set in order to use a cartoon grid. \emph{Note that many thorns will require cartoon-specific @@ -260,10 +248,10 @@ so. The three interface functions are: group)}] This function applies the cartoon boundary condition to the grid functions in the group specified by the \emph{group} parameter. - The parameter \emph{tensortype} parameter should be one of + The \emph{tensortype} argument parameter should be one of \begin{description} \item[\texttt{TENSORTYPE\_SCALAR}] a scalar; - \item[\texttt{TENSORTYPE\_U}] a vector (single, upper index). + \item[\texttt{TENSORTYPE\_U}] a vector (single, upper index); \item[\texttt{TENSORTYPE\_DDSYM}] a symmetric tensor with two lower indices. \end{description} @@ -303,9 +291,6 @@ are non-steerable, and so the routine must be run during the \texttt{CCTK\_RECOVER\_PARAMETERS} time bin in order to work. (This time bin is run even when checkpoint recovery is not being used.) -% -% FIXME: What's the published reference? -% \begin{thebibliography}{9} \bibitem{Alcubierre-etal-2001} Miguel Alcubierre, Steven Brandt, Bernd Br\"ugmann, Daniel Holz, |