El 04/08/2011, a las 08:48, Shitij Bhargava escribi?: > Thank you very much for your reply. > > I am a summer trainee, and I talked to my guide about this, and now what I > want might be a little different. > > I really do want all the eigenvalues. There cannot be any compromise on that. > But please note that time is not much of a concern here, the much bigger > concern is of memory. Even if I can distribute the memory somehow for the > computation of all eigenvalues, that is fine. (doesnt matter if it takes a > huge amount of time, he is willing to wait). Can any slepc Eigensolver > distribute memory this way while solving for all eigenvalues ? > > I am sorry if what I am asking is obvious, I dont know much about distributed > memory, etc. also. I am stupid at this moment, but I am learning. > > Also, when I ran the slepc program on a small cluster, and then ran the top > command, I saw that while solving for eigenvalues, the program was already > using upto 500% CPU. Does this mean that the eigensolver was "distributing > memory" automatically among different nodes ? I understand that it must be > distributing computational effort, but how do I know if it was distributing > memory also ? It simply showed me the RES memory usage to be 1.3 gb, and the > %MEM to be about 17%. Also, I did not use any MPIXXX data structures. I > simply used SeqAIJ. Will using MPIAIJ "distribute memory" while solving for > all eigenvalues ? (I understand that it will distribute memory to store the > matrix, but the memory bottleneck is eigenvalue solver, so its more important > for memory to be distributed then ) My guide said that one node will not have > enough memory, but all nodes combined will, and hence the requirement of > memory to be distributed. > > I read about ScaLAPACK, and I have already asked on their forums to confirm > if it is suitable for me. I am waiting for an answer. > > Thank you once again. > > Shitij
Try something like this: $ mpirun -np 8 ./program -eps_nev 4800 -eps_mpd 400 -eps_largest_real $ mpirun -np 8 ./program -eps_nev 4800 -eps_mpd 400 -eps_smallest_real But this may not work for the smallest ones. Jose
