What is the parallel MPI version of GARLI? Should I use it?
This is a fairly complex question and answer. The short of it is that if you are running on a large computer cluster it may be worthwhile to use the parallel version. There is nothing wrong with using the serial version on a cluster if the cluster allows it, and there may not be much benefit to using the MPI version in this case. The MPI version can also be run on a standalone machine with multiple processors that has MPI installed, such as Linux or Mac OS X Leopard (10.5). See a detailed discussion of the MPI version here.
