Day 114

Day 114 (actually, it's still Day 113 for me now, biologically, since I haven't went to bed since the last post): Well, it's time to wrap it up

Just a quick update to the last note: hardware architectures of all nodes have to be the same. I.e. making a 64-bit machine and a 32 one run one parallel task together won't work (at least I don't see how they could do it). How can I explain this? Well, before running a parallel task, you need to have your programme and all libraries that it uses (including OpenMPI) compiled. It is obvious that an executable compiled on a 64-bit machine won't run on a 32-bit machine, but MPI requires each node to be able to run the same executables, so there you go - you cannot combine machines with different architectures into one cluster to run parallel jobs, it will not work.

[update added MUCH later] While theoretically MPI can work on a heterogeneous cluster, I still have no clue how to do that and if it would make any sense with Topographica
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Anyway, I found out that running topographica on 3 Jupiter nodes is faster than on one Jupiter node with the same number of processes launched, which was a nice surprise right at the end of this project. I got the maximum performance optimisation factor of 3 (i.e. MPI versoin can get up to 3 times faster than the original sequential model) and I believe that at this stage I will not make it any faster since this is almost the end of the project and I haven't even started writing my report yet.

So, this is it...



P.S. I will do some benchmarking in the following 1.5 weeks and post the results here, so stay tuned. It's not like I'm abandoning this blog now anyway ;)