The ABINIT Users Mailing List ( CLOSED )

[marc.torrent@cea.fr]

Dear Jason,

The answer is quite simple:
This is not a normal behaviour of the PAW feature.

Let us remind you that:
1- In PAW, there is an atomic part to compute in addition to the "plane 
waves" part (the one of the norm-conserving case).
2- But the size of PW basis to get a good convergency are smaller in PAW. So 
you  MUST  decrease the needed CPU time.
3- You do not have to compare PAW and MT with the same cut-off.

4- Which version of Abinit do you use ? (this is a compulsory information to 
give when posting on the forum). Abinit PAW features are in v4.4.x in "beta 
test" stage (and very slow in earlier versions). This "beta test" 
characteristic will be suppressed in the future v4.5 version (end of January).
A lot of bugs remains in the <=v4.4.x versions.
In addition this new version will be (quite) bug free, faster and have new 
capabilities such as forces and stresses.

5- If you downloaded the PAW atomic data on the web site, you must have 
noticed that:
- the PAW file includes more valence electrons (16) than the MT one (8) (more 
cpu time needed).
- the PAW data might have core radii differents from the MT ones (it has a 
great influence on the computation speed).
- the present PAW atomic data (on the web site) are only examples and not 
optimized. In the next version (end of January) will plan to include new PAW 
optimized data (we are now working on it). 


Regards,

Marc Torrent and Francois Jollet
CEA-Bruyeres-le-Chatel - France

 


----------------------------------------------------------
# From: "H.L.Shih" <hlshih@gate.sinica.edu.tw>
# To: forum@abinit.org
# Subject: PAW pseudopotential
# Date: Thu, 16 Dec 2004 21:20:51 +0800 (CST)


Dear Abinit Users,

I tried to adopt PAW pseudopotential for simple Fe bulk, but found that
the cost is about ten times slower comparing with ordinary TM type
pseudopotential.

Table I. validation of bcc-Fe on ibm, pwr4 with two processors:
=========================
pot type cpu time
(sec.)
-------------------------
TM 5.4
PAW 50.7
=========================

is there any parameter I can tune to make it faster? or this is quite
normal when dealing with PAW. Thanks in advance.

BR,
J

-- 
---------------------------------
Jason Shih
Academia Sinica Computer Center
No.128, Sec. 2, Academia Rd.,
Nangang District, Taipei City 115,Taiwan (R.O.C.)
Tel: +886-2-27899960
Fax: +886-2-27899949
---------------------------------