Hybrid parallel programming with tasks

This technical report is an introduction to using a hybrid parallel programming model that combines MPI with OmpSs or OpenMP dependent tasks.  This model allows both computation and communication to be expressed using a coarse-grained dataflow approach, which helps to remove most of the unnecessary ordering constraints and intranode synchronisation imposed by the more conventional approach of MPI with OpenMP parallel loops. The report describes the model, and how it is supported by an augmented MPI library which interoperates with the tasking runtimes. It also assesses some of the advantages and disadvantages of this style of parallel programming.