[Pw_forum] about example06

[Eric Abel]

You're right, it does take a lot of time...for me it took about 3-5 days per 
k-point.  Make sure that you are using the crystal symmetry...that saves 
time.  I'm just curious...if you know the atomic displacements, why do you 
need to run a basic principles calculation?  If you want to only calculate a 
few modes, I believe it is possible to limit the number of modes that are 
calculated.  I've not done this, but I remember seeing this on either the 
input of the nscf phonon calculation or the phonon calculation itself using 
the pwgui interface.  There's a field where you can specify the number of 
modes.  You might want to play around with this.  Otherwise, the only other 
solution if you don't want to wait, is to find yourself a faster computer.

Eric

>From: "Ezad Shojaee" <ezadshojaee at hotmail.com>
>Reply-To: pw_forum at pwscf.org
>To: pw_forum at pwscf.org
>Subject: [Pw_forum] about example06
>Date: Tue, 04 Jul 2006 10:59:26 +0000
>
>hi Eric
>thanks for your time.i wanted to know that shouldn't we specify the 
>displacements of atoms in the input file? ( for example ,if i want to 
>calculate some special modes )  in  my case, i have a base with 6 atoms, i 
>had run a phonon calculation & it takes a lot of time !
>thanx again
>
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