Problem on Blue Gene/P

[Julien Bodart]

Hi everybody,

I am doing some CFD on a Blue Gene/P computer (40 thousand cores). I am
trying to use parallel Netcdf, as I originally used Netcdf-3 format.
Everything works fine on small cases(10 millions grid points), but when
going to bigger cases (1000 millions grid-points) problems arise. I tried to
use the 64 bits flag, which does not improve the matter.
Actually I am trying to write 64 files whose size is lower than 1GB, using
some subcommunicators.
While it does not create any problems on small cases, bigger cases stop at
the ncmpi_enddef call on some files (randomly, even with synchronisation in
between), saying that there is a mismatch between dimensions. After many
check it does not seems that there is something wrong with the dimensions. I
have no idea of how to solve the problem. Did anyone had similar problem?
Thanks for your help.

Julien
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