On Wed, 17 Nov 2010, Gus Correa wrote:
For what is worth, the MPI addresses (a.k.a. pointers) in the Fortran bindings are integers, of standard size 4 bytes, IIRR. Take a look at mpif.h, mpi.h and their cousins to make sure. Unlike the Fortran FFTW "plans", you don't declare MPI addresses as big as you want, MPI chooses their size when it is built, right? As Pascal pointed out, 4-byte integers would flip sign at around 2GB, and even unsigned integers won't go beyond 4GB. Would this be part of the problem?
yes, I think is the most probable explanation. I've solved it by using several processes to write the file (after all I just didn't want to program a bunch of checkups required for spanning several processes for such a simple thing...)
I guess all the OpenMPI pros and developers are busy now in Bourbon Street, New Orleans, I mean, at Supercomputer 2010. Hard to catch their attention right now, but eventually somebody will clarify this.
oh, just a small grain of sand... doesn't seems worth to stop the full machine for it...
:) many thanks all Ricardo Reis 'Non Serviam' PhD candidate @ Lasef Computational Fluid Dynamics, High Performance Computing, Turbulence http://www.lasef.ist.utl.pt Cultural Instigator @ Rádio Zero http://www.radiozero.pt Keep them Flying! Ajude a/help Aero Fénix! http://www.aeronauta.com/aero.fenix http://www.flickr.com/photos/rreis/ contacts: gtalk: kyriu...@gmail.com skype: kyriusan < sent with alpine 2.00 >
