[Pw_forum] degauss opt

Tue Feb 7 12:16:45 CET 2017

Thanks Pietro!

I was going to say that there is an extensive tutorial on this on
theossrv1.epfl.ch, but the machine will be down for 2-3 days (once
is back up, Mohammad can check it).

One small correction - "-TS" is negative (in the limit of small smearing,
that is always the case in our calculations) for gaussian or
fermi-dirac smearing, but can have either sign for cold smearing or
methfessel-paxton - since it's related to the first (or higher)
derivative of the density of states with respect to the energy,
at the Fermi energy (see de Gironcoli PRB 1995).

				nicola

On 07/02/2017 10:10, Pietro Delugas wrote:
> Dear Mohammad
>
> When you perform a calculation with smearing your  variational total
> energy  has an additional term which in the final PW summary of
> contributions to total energies is labeled  (-TS).
>
> This term is expected to be negative, and proportional to the value
> of degauss you are using. Which is what you  are observing.
>
> The appropriate value for degauss depends on the precision you need
> for total energy and on how many k-points you can afford  to use in
> your calculation.
>
> You should chose a value of degauss for which the absolute value of
> the -TS contribution is smaller than the precision you need to
> achieve.  On the other hand the smaller the value of  degauss you
> use, the denser will be the needed k-point mesh to reach
> convergence.
>
> greetings - pietro
>
>
> On 07/02/2017 08:31, mohammadreza hosseini wrote:
>>
>> Dear all
>>
>> I am performing optimization of degauss for a MOF structure. As I
>> decrease degauss, The total energy increases. What is the problem?
>> Is it possible describe how to obtain proper number for degauss?
>>
>>
>> Best
>>
>> -----Original Message----- From: pw_forum-request at pwscf.org To:
>> pw_forum at pwscf.org Date: Mon, 06 Feb 2017 12:00:03 +0100 Subject:
>> Pw_forum Digest, Vol 115, Issue 6
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>> Today's Topics:
>>
>> 1. Re: installation error: linking to Fortran libraries from C
>> fails (Amel Alhassan)
>>
>>
>> ----------------------------------------------------------------------
>>
>>
>>
Message: 1
>> Date: Mon, 6 Feb 2017 00:23:35 +0300 From: Amel Alhassan
>> <alhassan.amel at gmail.com <mailto:alhassan.amel%40gmail.com>>
>> Subject: Re: [Pw_forum] installation error: linking to Fortran
>> libraries from C fails To: PWSCF Forum <pw_forum at pwscf.org
>> <mailto:pw_forum%40pwscf.org>> Message-ID:
>>
>> <CA+mzp40G6H-3p6OzF3JccZ=EeRB+YHX8VJDV6K6jajjk6aQYvw at mail.gmail.com
>>
>>
<mailto:EeRB%2BYHX8VJDV6K6jajjk6aQYvw%40mail.gmail.com>>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Hello,
>>
>> I downloaded colorgcc from here
>>
>> http://packages.ubuntu.com/precise/all/colorgcc/download
>>
>> Then, I was able to run ./configure successfully.
>>
>> Then
>>
>> $ make all
>>
>>
>> ran for quiet some time and ended with
>>
>> gfortran -o xspectra.x  xspectra.o ./xspectra_mod.o ./radin_mod.o
>>> ./mygetK.o ./ipoolscatter.o ./lr_sm1_psi.o ./orthoUatwfc_k.o
>>> ./read_k_points.o ./reset_k_points_and_reinit.o ./paw_gipaw.o
>>> ./gipaw_module.o ./init_gipaw_1.o ./init_gipaw_2.o \
>>
>> ../../PW/src/libpw.a  ../../Modules/libqemod.a -g -pthread
>>> ../../iotk/src/libiotk.a ../../flib/flib.a ../../clib/clib.a
>>> ../../flib/ptools.a  -llapack  -lblas  -lfftw3  -lblas
>>
>> ( cd ../../bin ; ln -fs ../XSpectra/src/xspectra.x . )
>>
>> make[3]: Leaving directory
>> `/home/amel/espresso-5.1.1/XSpectra/src'
>>
>> make[2]: Leaving directory `/home/amel/espresso-5.1.1/XSpectra'
>>
>> touch make-xspectra
>>
>> make[1]: Leaving directory `/home/amel/espresso-5.1.1/install'
>>
>>
>>
>>
>> I assume there is nothing wrong; unless make[ ] means an error(?!)
>>
>> I guess I am equipped to do some simulations now :-)
>>
>> Thank you very much Paolo and Phanikumar Pentyala
>>
>> Best regards, Amel
>>
>> On Sat, Feb 4, 2017 at 8:47 PM, Amel Alhassan
>> <alhassan.amel at gmail.com <mailto:alhassan.amel%40gmail.com>>
>> wrote:
>>
>>> Thank you Paolo for translation :D I couldn't get what was the
>>> error actually.
>>>
>>> Ok, now checking for gcc and colorgcc, it seems like there is
>>> gcc installed but no colorgcc and I can't even install it.
>>>
>>> running
>>>
>>>> $ sudo apt-get install colorgcc
>>>
>>> I get
>>>
>>>> E: Package 'colorgcc' has no installation candidate
>>>
>>>
>>> Can I make espresso use gcc instead? How?
>>>
>>> Kind regards, Amel
>>>
>>>
>>> On Sat, Feb 4, 2017 at 7:14 PM, Paolo Giannozzi
>> <p.giannozzi at gmail.com <mailto:p.giannozzi%40gmail.com>>
>>> wrote:
>>>
>>>> Out of the hundreds of lines you posted, the only relevant
>>>> ones:
>>>>
>>>>>> /usr/bin/colorgcc -O3 -D__GFORTRAN -D__STD_F95 -D__FFTW3
>>>> -I../include  -c customize_signals.c
>>>>>>
>>>>>> make[1]: /usr/bin/colorgcc: Command not found
>>>>
>>>> clearly show that you are trying to use "/usr/bin/colorgcc" as
>>>> C compiler, and that there is no "/usr/bin/colorgcc" in your
>>>> system
>>>>
>>>> Paolo _______________________________________________ Pw_forum
>>>> mailing list Pw_forum at pwscf.org <mailto:Pw_forum%40pwscf.org>
>>>> http://pwscf.org/mailman/listinfo/pw_forum
>>>>
>>>
>>>
>>>
>>> -- Amel Shamseldeen Ali Alhassan Lecturer Nile College Khartoum,
>>> Sudan +249 915382411
>>>
>>
>>
>>
>> -- Amel Shamseldeen Ali Alhassan Lecturer Nile College Khartoum,
>> Sudan +249 915382411 -------------- next part -------------- An
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project