real space grid decomposition
no... at bollweevil.gdbg.org
Fri Apr 22 22:47:49 CEST 2011
Am I correct in surmising that real space grids are decomposed over nodes only
along the 1st dimension?
I'm reaching a parallelization bottleneck for QM/MM. If I do atom
I get pw_restrict_s3 and corresponding routines that take a lot of
time and don't
speed up. If I do grid based parallelization I get no speedup once
the number of
parallel processes is comparable to the size of the 1st dimension of the real
space grid (-18..18 = 39 in my case). With 32 processes I get some
but poor load balance, because some processes do grid x value and some do 2.
For 64 processes some processes are actually doing no work in
qmmm_forces_with_gaussian_LG(), for example
Is there anything I'm missing?
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