[CPMD-list] NCACHE size

[Alessandro Curioni]

> btw: the best way to optimize the fft is use it as little as
> possible (e.g. by using the REAL SPACE WFN KEEP keyword, provided
> there is enough memory on your machine).

Yes,

keeping  the real space wavefuntions can save a  lot of time, and
differentiate  machines with large memory available
 with respect to machines with a small memory, and should be used whenever
possible ( if you want to test CPMD on diverse machines).
The same is true for the mixed OpenMP/MPI; e.g. use the appropriate mixing
when this help.

BTW: the intent to use  exactly the same input file with the idea the code
will do  the same number of operations is wrong  , i.e.
different architectures use diverse  optimized ffts that are available  for
different grid sizes - to  tell you only one.


Regards,




Alessandro CURIONI, PhD
Research Staff Member
Computational Biochemistry and Material Science group
IBM Research Division - Zurich Research Laboratory
Saumerstrasse 4
8003 Rueschlikon - Switzerland
e-mail: cur at zurich.ibm.com
www:    www.zurich.ibm.com
Tel: +41-1-7248633
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