Simple MPI/FORTRAN Applications

2.8 Summary

In this chapter, a brief summary of how to write simple parallel MPI/FORTRAN codes has been presented and explained. Through two simple examples (given in Sections 2.2 – 2.3), it is rather obvious that writing parallel MPI/FORTRAN codes are essentially the same as in the sequential mode of FORTRAN 77, or FORTRAN 90, with some specially added parallel MPIJFORTRAN statements. These special MPIJFORTRAN statements are needed for the purposes of parallel computation and Processors’ communication (such as sending/receiving messages, summing /merging Processor’s results, etc.). Powerful unrolling techniques associated with “dotproduct” and “saxpy” operations have also been explained. These unrolling strategies should be incorporated into any application codes to substantially improve the computational speed.