[gpaw-users] Error estimations for different XCs

[wei guo]

Thanks guys,

I see that get_xc_difference() is the method doing non-selfconsistently.
Or I can use the BEEF-vdw

When I try the example here,
https://wiki.fysik.dtu.dk/gpaw/documentation/xc/vdw.html
I got a error when running de_h2 = ens.get_ensemble_energies()
It said
BEEF-vdW ensemble started
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/shared/ase/3.7.1.3184/ase/dft/bee.py", line 41, in
get_ensemble_energies
    self.contribs = self.calc.get_nonselfconsistent_energies(self.beef_type)
AttributeError: GPAW instance has no attribute
'get_nonselfconsistent_energies'

Jess, did I miss some modules？
Thanks



On Tue, Sep 10, 2013 at 3:37 AM, Jens Jørgen Mortensen
<jensj at fysik.dtu.dk>wrote:

>  Den 10-09-2013 01:58, Wellendorff, Jess skrev:
>
> Dear Wei,
>
>  a much more systematic approach to your quest is to use the BEEF-vdW
> functional with the corresponding Bayesian Error Estimation Ensemble.
> This ensemble actually does exactly what you are looking for without the
> need for you to specify which "standard functionals" define the spread of
> DFT results. Instead, the error estimate (or estimate of the spread of
> predictions by different density functionals) is calculated simply as the
> square root of the variance over the BEEF-vdW ensemble predictions. Search
> for "BEEF-vdW" on the GPAW web pages.
>
>  I really recommend this approach. It gives you a much less biased and
> more quantitative estimate of the sensitivity of your DFT result wrt the
> density functional you have chosen. Think about the inherent bias in this
> way: How can you be sure that you know by heart the two density functionals
> that would provide predictions at the two ends of the true distribution of
> DFT predictions of the quantity you are interested in ??? That is very
> hard, if not impossible. But the BEE approach offers a convenient and cheap
> estimate of how much your DFT prediction would change had you chosen other
> XC functionals than the BEEF-vdW one (provided the quantity of interest is
> posed in terms of total energies).
>
>
> Here is a simple example showing how to calculate the energy for another
> functional non-selfconsistentily (look at the PBE.py file):
>
>   https://wiki.fysik.dtu.dk/gpaw/exercises/iron/iron.html
>
> Jens Jørgen
>
>
>  Best
> Jess Wellendorff
>
>  On Sep 9, 2013, at 11:49 PM, Glen Jenness wrote:
>
>  Dear Wei,
>
>  Off the top of my head you can do something like :
>
>  calc = GPAW(....)
>
>  potentials = ['PBE', 'LDA', 'PW91']
>
>  for xc in potentials:
>     calc.set(xc=xc)
>     <calculate binding energy here>
>
>  This will actually work with most of the ASE calculators.
>
>  Glen
>
>
>
>
> On Mon, Sep 9, 2013 at 5:18 PM, wei guo <guoweicyclone at gmail.com> wrote:
>
>> Hi guys,
>>
>>  We are interested in calculate the binding energies using different XC
>> to get a sense how the errors are related to XCs.
>>
>>  To save time, I guess one can start from the relaxed structure and in
>> one calculation obtain all the potential energies of a few XCs.
>>
>>  Is there any function or module in GPAW or ASE for doing this
>>
>>  Thanks.
>> --
>> Best wishes
>> Wei
>> ----------------------------------------------------------------
>> 353 Colburn Lab
>> Center for Catalytic Science and Technology
>> Department of Chemical Engineering
>> University of Delaware
>> Newark, DE 19716-3111
>> Tel:(302)-831-1132
>>  ----------------------------------------------------------------
>>
>> _______________________________________________
>> gpaw-users mailing list
>> gpaw-users at listserv.fysik.dtu.dk
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>>
>
>
>
>  --
> Dr. Glen Jenness
> Schmidt Group/Morgan Group
> Department of Chemistry/Materials Science and Engineering (MSAE)
> University of Wisconsin - Madison
>  _______________________________________________
> gpaw-users mailing list
> gpaw-users at listserv.fysik.dtu.dk
> https://listserv.fysik.dtu.dk/mailman/listinfo/gpaw-users
>
>
>  -----------------------------------------------------------------------
> Dr. Jess Wellendorff
> Postdoctoral Researcher
> SUNCAT Center for Interface Science & Catalysis
> SLAC National Accelerator Laboratory, U.S.A.
> -----------------------------------------------------------------------
>
>
>
> _______________________________________________
> gpaw-users mailing listgpaw-users at listserv.fysik.dtu.dkhttps://listserv.fysik.dtu.dk/mailman/listinfo/gpaw-users
>
>
>


-- 
Best wishes
Wei
----------------------------------------------------------------
353 Colburn Lab
Center for Catalytic Science and Technology
Department of Chemical Engineering
University of Delaware
Newark, DE 19716-3111
Tel:(302)-831-1132
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