The \eslmod{mpi} module contains a small number of utilities useful for using an MPI (Message Passing Interface) library for parallelization. Table~\ref{tbl:mpi_api} lists the routines in the \eslmod{mpi} API. \begin{table}[hbp] \begin{center} {\small \begin{tabular}{|ll|}\hline \hyperlink{func:esl_mpi_PackOpt()}{\ccode{esl\_mpi\_PackOpt()}} & Pack an optional, variable-sized array (or string).\\ \hyperlink{func:esl_mpi_PackOptSize()}{\ccode{esl\_mpi\_PackOptSize()}}& Determine the size of a packed optional, variable-sized array.\\ \hyperlink{func:esl_mpi_UnpackOpt()}{\ccode{esl\_mpi\_UnpackOpt()}} & Unpack an optional, variable-sized array (or string).\\ \hline \end{tabular} } \end{center} \caption{The \eslmod{mpi} API.} \label{tbl:mpi_api} \end{table}