Hi Barnabas As far as i know, Open-MPI is not a shared memory system.
Using Open-MPI to attack your problem on N processors, i would poceed as follows: - processor 0 reads the table and then splits it into N parts (Table_0,...Table_N) - processor 0 sends Table_i to processor i (for all i > 0) using MPI functions - if processor k needs info from Table_j, processor k sends a request to processor j - processor j sends requested information to processor k Of course you'd need some scheme to find out on which Table_i a particular entry can be found. This solution will work as well if your processors sit on several hosts. Jody On Tue, Apr 28, 2009 at 3:28 PM, Barnabas Debreczeni <k...@goa.hu> wrote: > Hi! > > I am new to this list and to parallel programming in general. I am > writing a trading simulator for the forex market and I am using > genetic algorithms to breed trading parameters. > > I am using PGAPack as a GA library, and it uses MPI to parallelize > optimization runs. This is how I got to Open MPI. > > I am stuck at some point mainly because my lack of parallel > programming knowledge. What I'd like to achieve is: (I am doing it the > serial way right now) > > - Load price data from files, and compute a few tables (right now this > takes up ~4 GB of memory) > - Repeat... > -- Create new offsprings in the master process for the GA > -- Evaluate them in parallel (on 4 local CPUs but maybe more on LAN if > i need it) > - Until I get a satisfactory result. > > > My problem is, I'd like to share that 2 GB table (computed once at the > beginning, and is read-only after) between processes so I don't have > to use up 16 gigs of memory. > > How do you share data between processes locally? > > Later I will need to use other hosts too in the calculation. Will the > slaves on other hosts need to calculate their own tables on go on from > there and share them locally, or can I share these tables on the > master host with them? > > How do you usually solve these kinds of problems? > > Can you point me to some docs or keywords what should I learn about? > > Thank you very much. > > Regards, > > Barnabas > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
