[Pw_forum] stress in CP vs PW, previously no subject
Eduardo Ariel Menendez P
emenendez at macul.ciencias.uchile.cl
Thu Feb 16 20:51:20 CET 2006
Thank you Stefano for your prompt advise.
I repeated the CP minimization commenting qcutz=150., q2sigma=2.0, ecfixed=24.0.
I read that default value is ecfixed=40, which is larger than my cutoff for the
wavefunction, then I guess that this does not affect the calculation. There is
no much difference in the stress nor in the energy with respect to the
calculation using qcutz=150., q2sigma=2.0, ecfixed=24.0.
I also changed the occupation to fixed with pwscf, and set ecfixed, qcutz and
q2sigma. I also set ibrav=14 to match the CP job.
The numbers with pw.x also change little change. Then I have a significant
difference in the pressure of 29 kbar with pw vs -100 GPa with CP.
Below is the summary of the last steps of CP miinimization with damped dynamics
(I pasted it wrongly in the previous mail)
nfi ekinc temph tempp etot enthal econs econt
vnhh xnhh0 vnhp xnhp0
200 0.00772 0.0 0.0 -2096.99556 -2096.99556 -2096.99556 -2096.98785
0.0000 0.0000 0.0000 0.0000
writing restart file: .//cdte64_91.save
restart file written in 24.895 sec.
201 0.00753 0.0 0.0 -2096.99846 -2096.99846 -2096.99846 -2096.99093
0.0000 0.0000 0.0000 0.0000
202 0.00735 0.0 0.0 -2097.00129 -2097.00129 -2097.00129 -2096.99394
0.0000 0.0000 0.0000 0.0000
203 0.00717 0.0 0.0 -2097.00405 -2097.00405 -2097.00405 -2096.99687
0.0000 0.0000 0.0000 0.0000
204 0.00700 0.0 0.0 -2097.00675 -2097.00675 -2097.00675 -2096.99974
0.0000 0.0000 0.0000 0.0000
205 0.00684 0.0 0.0 -2097.00938 -2097.00938 -2097.00938 -2097.00254
0.0000 0.0000 0.0000 0.0000
206 0.00668 0.0 0.0 -2097.01196 -2097.01196 -2097.01196 -2097.00527
0.0000 0.0000 0.0000 0.0000
207 0.00653 0.0 0.0 -2097.01447 -2097.01447 -2097.01447 -2097.00794
0.0000 0.0000 0.0000 0.0000
208 0.00638 0.0 0.0 -2097.01693 -2097.01693 -2097.01693 -2097.01055
0.0000 0.0000 0.0000 0.0000
209 0.00623 0.0 0.0 -2097.01934 -2097.01934 -2097.01934 -2097.01310
0.0000 0.0000 0.0000 0.0000
210 0.00609 0.0 0.0 -2097.02169 -2097.02169 -2097.02169 -2097.01559
0.0000 0.0000 0.0000 0.0000
211 0.00596 0.0 0.0 -2097.02399 -2097.02399 -2097.02399 -2097.01803
0.0000 0.0000 0.0000 0.0000
212 0.00582 0.0 0.0 -2097.02623 -2097.02623 -2097.02623 -2097.02041
0.0000 0.0000 0.0000 0.0000
213 0.00570 0.0 0.0 -2097.02843 -2097.02843 -2097.02843 -2097.02274
0.0000 0.0000 0.0000 0.0000
214 0.00557 0.0 0.0 -2097.03059 -2097.03059 -2097.03059 -2097.02501
0.0000 0.0000 0.0000 0.0000
215 0.00545 0.0 0.0 -2097.03269 -2097.03269 -2097.03269 -2097.02724
0.0000 0.0000 0.0000 0.0000
216 0.00533 0.0 0.0 -2097.03475 -2097.03475 -2097.03475 -2097.02942
0.0000 0.0000 0.0000 0.0000
217 0.00522 0.0 0.0 -2097.03677 -2097.03677 -2097.03677 -2097.03155
0.0000 0.0000 0.0000 0.0000
218 0.00511 0.0 0.0 -2097.03875 -2097.03875 -2097.03875 -2097.03364
0.0000 0.0000 0.0000 0.0000
219 0.00500 0.0 0.0 -2097.04068 -2097.04068 -2097.04068 -2097.03568
0.0000 0.0000 0.0000 0.0000
nfi ekinc temph tempp etot enthal econs econt
vnhh xnhh0 vnhp xnhp0
220 0.00490 0.0 0.0 -2097.04257 -2097.04257 -2097.04257 -2097.03768
0.0000 0.0000 0.0000 0.0000
This was with the default values of ecfixed, etc. The corresponding pwscf
energy (occupation=fixed) is -2097.047 Ha.
Eduardo
>
> Today's Topics:
>
> 1. Re: (no subject) (degironc)
> 2. Where to get CVS version of Q-Espresso? (Huiqun Zhou)
> 3. Total number of d electrons of cobalt (Huiqun Zhou)
> 4. Re: Where to get CVS version of Q-Espresso? (Miguel Martinez)
> 5. Re: question about pwcond.x (Gabriel =?iso-8859-1?Q?Aut=E8s?=)
> 6. Re: Total number of d electrons of cobalt (Matteo Cococcioni)
> 7. Problem relaxing cluster (Lucas Fernandez Seivane)
> 8. Re: Problem relaxing cluster (Silviu Zilberman)
>
> --__--__--
>
> Message: 1
> Date: Wed, 15 Feb 2006 09:23:03 +0100
> From: degironc <degironc at sissa.it>
> To: pw_forum at pwscf.org
> Subject: Re: [Pw_forum] (no subject)
> Reply-To: pw_forum at pwscf.org
>
> stress converges slowly with cutoff and if you are not at full
> convergence
> setting the variables qcutz=150., q2sigma=2.0, ecfixed=24.0, modifies
> the kinetic energy
> of the electrons beyond 24 ry adding a large penalty function and the
> "effective" cutoff of your
> calculation is something around 24 ry.
> This affects the total energy and the stress.
> Also having smearing instead of fixed occupation makes a difference but
>
> if your system is gapped it should not be large.
> In order to compare output of the two codes you should use the same
> setting in both.
>
> stefano
>
>
> CP>
>
> > &SYSTEM
> > ibrav = 14,
> > celldm(1) = 24.4946,
> > celldm(2) = 1.0,celldm(3) = 1.0,celldm(4) =
> 0.0,celldm(5) = 0.0,celldm(6) = 0.0,
> > nat = 64,
> > ntyp = 2,
> > nbnd=288,nelec=576,nspin=1,
> > ecutwfc = 30.0 ,
> > ecutrho = 240 ,
> > occupations = 'fixed' ,
> > xc_type = 'PBE',
> >
> > qcutz=150., q2sigma=2.0, ecfixed=24.0,
> > /
> >
> PW>
>
> > &SYSTEM
> > ibrav = 1,
> > celldm(1) = 24.4946,
> > nat = 64,
> > ntyp = 2,
> > ecutwfc = 30.0 ,
> > ecutrho = 240 ,
> > occupations = 'smearing' ,
> > degauss = 0.02 ,
> > smearing = 'fermi-dirac' ,
> > /
> > &ELECTRONS
> >
> >
>
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