ABSTRACT
There are two implementations in GAMESS for the parallelization. One is using Transmission Control Protocol/Internet Protocol (TCP/IP) and the other one is using Message Passing Interface (MPI). TCP/IP has been around for a very long time so that it is in the operating system as a standard piece. This makes it much easier to write scripts for compiling and linking for GAMESS. MPI gives a very clean programming standard, so that the code can be the same on all machines. For slow network, TCP/IP is almost the same efficiency as MPI. While for fast networks, such as Infiniband network, the MPI library might have been tuned to run more efficiently. In this work, we implement MPI for GAMESS so that it can run more efficiently than TCP/IP. Our tests show a factor often in the efficiency can be gained if MPI is properly implemented.
