X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=doc%2Fctsim-concepts.tex;h=bacfd4b4807969b66469c0833c9c682d08ee9c02;hb=7df269f65639c1a862a58649c48331824029128a;hp=3f0bb1640554d5fe31f0415e017792f94566b778;hpb=21362871030affef16ed3f135ac36349476416b5;p=ctsim.git diff --git a/doc/ctsim-concepts.tex b/doc/ctsim-concepts.tex index 3f0bb16..bacfd4b 100644 --- a/doc/ctsim-concepts.tex +++ b/doc/ctsim-concepts.tex @@ -301,7 +301,7 @@ length}. This length, \latexonly{\begin{equation} d_l = 4\,f \tan (\alpha / 2)\end{equation}} \latexignore{\\\centerline{\emph{4 x F x tan(\alpha/2)}}} \latexonly{This geometry is shown in figure~\ref{equilinearfig}.} -\begin{figure}\label{equilinearfig} +\begin{figure} \centerline{\image{10cm;0cm}{equilinear.eps}} \latexonly{\caption{\label{equilinearfig} Equilinear geometry}} \end{figure} @@ -316,7 +316,7 @@ accurate as filtered backprojection. This is due primarily to interpolation occurring in the frequency domain rather than the spatial domain. -\subsection{Filtered Backprojection}\index{Filtered backprojection} +\subsection{Filtered Backprojection}\index{Filtered backprojection}\index{Symmetric multiprocessing}\index{SMP} The technique is comprised of two sequential steps: filtering projections followed by backprojecting the filtered projections. Though these two steps are sequential, each view position can be processed independently. @@ -324,9 +324,18 @@ these two steps are sequential, each view position can be processed independentl \subsubsection{Parallel Computer Processing}\index{Parallel processing} Since each view can be processed independently, filtered backprojection is amendable to parallel processing. Indeed, this has been used in commercial scanners to speed reconstruction. -This parallelism is exploited in the MPI versions of \ctsim\ where the -data from all the views are spread about amongst all of the -processors. This has been testing in a cluster of 16 computers with excellent +This parallelism is exploited both in the \ctsim\ graphical shell and +in the \helpref{LAM}{ctsimtextlam} version of \ctsimtext. \ctsim\ can distribute it's workload +amongst multiple processors working in parallel. + +The graphical shell will automatically take advantage of multiple CPU's when +running on a \emph{Symmetric Multiprocessing} +computer. Dual-CPU computers are commonly available which provide a near doubling +in reconstruction speeds. \ctsim, though, has no limits on the number of CPU's +that can be used in parallel. The \emph{LAM} version +of \ctsimtext\ is designed to work in a cluster of computers. +This has been testing with a cluster of 16 computers in a +\urlref{Beowulf-class}{http://www.beowulf.org} cluster with excellent results. \subsubsection{Filter projections}