[Pw_forum] serial algorithm in parallel phonon calculation
Paolo Giannozzi
giannozz at nest.sns.it
Wed Aug 23 20:19:56 CEST 2006
On Wednesday 23 August 2006 18:32, Eduardo Ariel Menendez P wrote:
> Looking at the ph.x output, when running in parallel with four CPUs
> (-npool 1) I found the following intriguing report
> ***********************
> Calculation of q = 0.2500 0.2500 -0.2500
>
> looking for the optimal diagonalization algorithm ...
>
> a serial algorithm will be used
> ***********************
this refers to the "conventional" diagonalization, used in the
Davidson iterative diagonalization to diagonalize over a subspace.
It is an additional level of parallelization that may or may not be
convenient to have.
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 11020 eduardo 16 0 107m 20m 50m R 63.9 1.0 32:49.09 ph.x
> 11019 eduardo 16 0 107m 20m 50m S 21.6 1.0 11:22.56 ph.x
> and the same in the other dual node. Is it related to the algorithm?
no, it isn't. Are the two processing running on different CPU's?
it looks very lousy.
Paolo
--
Paolo Giannozzi e-mail: giannozz at nest.sns.it
Scuola Normale Superiore Phone: +39/050-509876, Fax:-563513
Piazza dei Cavalieri 7 I-56126 Pisa, Italy
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