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Diffstat (limited to 'doc/UsersGuide/ThornWriters.tex')
| -rw-r--r-- | doc/UsersGuide/ThornWriters.tex | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/doc/UsersGuide/ThornWriters.tex b/doc/UsersGuide/ThornWriters.tex index eb8aa9aa..f157d74c 100644 --- a/doc/UsersGuide/ThornWriters.tex +++ b/doc/UsersGuide/ThornWriters.tex @@ -745,6 +745,20 @@ $(SYS_OBJD)/MyRoutine.F.o: $(SYS_OBJD)/MyModule.F.o \end{verbatim} } +\subsubsection{The {\tt MOD} function} + +The intrinsic function {\tt MOD} in Fortran takes two integer +arguments, which should both be of the same type. This means +that it may be necessary to cast the arguements to {\it e.g} +{\tt INT} for some architectures. This can occur in particular +when a {\tt CCTK\_INT} parameter and the Cactus variable {\tt cctk\_iteration} +(which is declared to be {\tt INTEGER}) are used, +in which case the correct code is +{\tt +\begin{verbatim} +MOD(cctk_iteration,INT(MyParameter)) +\end{verbatim} +} \subsection{C Routines} @@ -816,6 +830,18 @@ void MyCRoutine(CCTK_CARGUMENTS) } \end{verbatim} +\subsubsection{Complex variables} + +Cactus supports complex grid variables, and since there is no +complex data type in C, Cactus provides a number +of functions for manipulating complex numbers to mirror the +functionality available in Fortran. These functions are {\tt CCTK\_Cmplx}, +{\tt CCTK\_CmplxReal}, {\tt CCTK\_CmplxImag}, {\tt CCTK\_CmplxConjg}, +{\tt CCTK\_CmplxAdd}, {\tt CCTK\_CmplxSub}, {\tt CCTK\_CmplxMul}, +{\tt CCTK\_CmplxDiv}, {\tt CCTK\_CmplxExp}, {\tt CCTK\_CmplSin}, +{\tt CCTK\_CmplxAbs}, {\tt CCTK\_CmplxLog}, {\tt CCTK\_CmplSqrt}. + + \subsubsection{Specifically for C Programmers} Grid functions are held in memory as 1D C arrays. These are laid |