[Wien] k point parallel mode

Peter Blaha pblaha at theochem.tuwien.ac.at
Fri Dec 30 12:44:01 CET 2011

> To "make" the file, you use an editor (nothing more or less) and putthe file in the directory where you are running the job. I have notlooked, but there is probably something in w2web to do this.
> N.B., the code does not use OMP anywhere (at present) so this will notdo anything.

Just a small correction: If you are using the mkl, OMP_NUM_THREADS will have an
effect in the diagonalization part of lapw1 (which is often the main part anyway).

However, while OMP_NUM_THREADS = 2 is quite effective and speeds up the diagonalization
significantly, =4 is far less efficient and = 6 is usually useless.

PS: On a 6 core machine you should run ONLY 6 jobs at the same time (or 3 k-parallel
jobs with OMP_NUM_THREADS=2) !!!
Intels "hyperthreading", which mimics "12 processors" to you, should even be switched
off (BIOS), because it will slow down the jobs.

Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at

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