[Pw_forum] Parallelization of diaghg

[Alexander Shaposhnikov]

On Sunday 07 January 2007 03:03, Axel Kohlmeyer wrote:

> hmmmm.... what version of pw.x are you referring to?
> at least in version 3.2 there should be a parallel diagonalization
> that is used in pw.x (subroutine cdiagonalize in Modules/ptoolkit.f90).
> as far as i understand, this is not easy to parallelize, so there
> is an estimator that checks, whether the serial or the parallel algorithm
> would be more efficient.

recent cvs.
with diagonalization='david +para', the code almost always chooses
parallel algorithm but this always increases total computation time,
both on Intel and AMD SMP machines.
So i guess the default 'david ' with serial diaghg is the best choice 
currently.

By the way, i have found that diago_david_ndim=2 gives better times  
and also saves alot of memory comparing with default =4.

Best Regards,
Alexander Shaposhnikov
> cheers,
>    axel.
>