Learning by doing :: MPI -- Virtual Topologies In MPI, Part 3

This video is part of the new series called "Learning by doing :: MPI" which serves as an introductory course on MPI (Message Passing Interface). In this video we talked about virtual topologies in MPI! This topic corresponds to chapter 8 of the MPI standard v4.1. It is a lengthy chapter with a lot of information to digest. We followed the same pattern as for "Datatypes in MPI" by dividing a chapter into digestible ~25 mins long parts. In part 3 we continued our discussion by checking variations for MPI_Graph_create which we didn't have time to finish in Part 2. We asked three main questions namely are we allowed to have self-loop pattern in our graph topology? Are we allowed to have repetitive sources/destinations in our graph topologies? Are we allowed to have non-symmetric adjacency matrix in our graph topologies? And the answer to all three questions was absolutely YES! Then we moved on MPI_Dist_graph_create_adjacent and MPI_Dist_graph_create graph topology constructors which are the distributed versions of the general graph cases. In these constructors each MPI process only knows about the edges and processes that it is aware of! In the case of MPI_Dist_graph_create_adjacent each process mentions all its incoming and outgoing edges. However, in the case of MPI_Dist_graph_create one has full flexibility to mention any edges in the graph. We have gone over the same simple example in the MPI standard for those topology constructors. Finally, we stopped at the beginning of inquiry functions for virtual topologies.

All the necessary info you need for MPI standard can be downloaded from here : https://www.mpi-forum.org/docs/mpi-4....

If you want to download MPICH, please visit here : https://www.mpich.org/downloads/
* The latest version at the time of this video is mpich-4.2.2

Hope you learned something from this video. If you have further questions don't hesitate to comment down below. Have fun!