Also the sequential mapper may be of help - allows you to specify the node each rank is to be place on, one line/rank.
On Mar 1, 2012, at 12:40 PM, Gustavo Correa wrote: > Hi Claudio > > Check 'man mpirun'. > You will find examples of the > '-byslot', '-bynode', '-loadbalance', and rankfile options, > which allow some control of how ranks are mapped into processors/cores. > > I hope this helps, > Gus Correa > > On Mar 1, 2012, at 2:34 PM, Claudio Pastorino wrote: > >> Hi, thanks for the answer. >> You are right is not the rank what matters but how do I arrange >> the physical procs in the cartesian topology. I don't care about the label. >> So, how do I achieve that? >> >> Regards, >> Claudio >> >> >> >> 2012/3/1, Ralph Castain <r...@open-mpi.org>: >>> Is it really the rank that matters, or where the rank is located? For >>> example, you could leave the ranks as assigned by the cartesian topology, >>> but then map them so that ranks 0 and 2 share a node, 1 and 3 share a node, >>> etc. >>> >>> Is that what you are trying to achieve? >>> >>> >>> On Mar 1, 2012, at 11:57 AM, Claudio Pastorino wrote: >>> >>>> Dear all, >>>> I apologize in advance if this is not the right list to post this. I >>>> am a newcomer and please let me know if I should be sending this to >>>> another list. >>>> >>>> I program MPI trying to do HPC parallel programs. In particular I >>>> wrote a parallel code >>>> for molecular dynamics simulations. The program splits the work in a >>>> matrix of procs and >>>> I send messages along rows and columns in an equal basis. I learnt >>>> that the typical >>>> arrangement of cartesian topology is not usually the best option, >>>> because in a matrix, let's say of 4x4 procs with quad procs, the >>>> procs are arranged so that >>>> through columns one stays inside the same quad proc and through rows >>>> you are always going out to the network. This means procs are >>>> arranged as one quad per row. >>>> >>>> I try to explain this for a 2x2 case. The cartesian topology does this >>>> assignment, typically: >>>> cartesian mpi_comm_world >>>> 0,0 --> 0 >>>> 0,1 --> 1 >>>> 1,0 --> 2 >>>> 1,1 --> 3 >>>> The question is, how do I get a "user defined" assignment such as: >>>> 0,0 --> 0 >>>> 0,1 --> 2 >>>> 1,0 --> 1 >>>> 1,1 --> 3 >>>> >>>> ? >>>> >>>> Thanks in advance and I hope to have made this more or less >>>> understandable. >>>> Claudio >>>> _______________________________________________ >>>> users mailing list >>>> us...@open-mpi.org >>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >>> >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
