[Pw_forum] degauss opt

Tue Feb 7 10:10:13 CET 2017

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
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