[Pw_forum] convergence for CaMg2

adwait mevada adwait.mevada at gmail.com
Sun Oct 25 14:35:47 CET 2015


Dear Giovanni,
As per your suggestion I performed calculations with ecutrho 8 times
ecutwfc, obtaining following results
30     -932.77949435      1314.9516     40   459.04   7m51.69s
40     -932.78411921      1314.9516     40   459.17  12m10.64s
50     -932.78290292      1314.9516     40   458.79  16m20.76s
60     -932.78405904      1314.9516     40   458.76  20m21.45s
70     -932.78361561      1314.9516     72   458.85  57m33.02s
80     -932.78379443      1314.9516     40   458.68  32m52.95s
90     -932.78384952      1314.9516     40   458.90  39m24.40s
100     -932.78383671      1314.9516     40   458.73  43m 3.29s
110     -932.78386666      1314.9516     40   458.83  47m23.76s
120     -932.78385073      1314.9516     40   458.81  58m39.28s
130     -932.78388792      1314.9516     40   458.74      1h 5m
140     -932.78391298      1314.9516     40   458.82      1h12m
150     -932.78388192      1314.9516     40   458.80      1h21m
The fluctuations are still there but now less in comparisions (see graph)
Right now I am testing for 10x to see if fluctations reduce.
>From graph of 8x plot I feel ecutwfc=70 Ry and ecutrho=560 Ry seems
a good candidate for convergence. But it has higher number of Kpoints
compared to ecutwfc=80 Ry and also consumes more time
what do you suggest or will data from 10x run be more conclusive?

Thanks for your help.

Adwait Mevada,
Ph.D. Student,
Gujarat University,
Gujarat, India.

On Fri, Oct 23, 2015 at 9:09 PM, adwait mevada <adwait.mevada at gmail.com>
wrote:

> Dear Giovanni,
> Thanks for the prompt response, I will do as you suggested.
> The above data was obtained without fixing ecutrho to480 (it was
> commented) . I felt that may be a lower kpoint grid or wrong smearing might
> be the source.
> I will do as you suggested and get back to you.
> Thanks again.
> Adwait
> Ph.D. Student,
> Gujarat University,
> Gujarat, India.
> On 23-Oct-2015 8:56 pm, "Giovanni Cantele" <giovanni.cantele at spin.cnr.it>
> wrote:
>
>> one of the problems that you might be running across is that you keep
>> ecutrho fixed. That means that with ecutwfc=30, ecutrho/ecutwfc=16, whereas
>> with ecutwfc=120, the same ratio is 4. The latter is definitely too small
>> for ultrasoft pseudo potentials, that you are including in your
>> calculation. In other words, you might be comparing values of the total
>> energies with different convergence levels with respect to ecutrho, which
>> can be the origin (or a partial explanation) of the oscillations you find.
>>
>> I would try (maybe this will not solve your problem!) to retry the test
>> as a function of ecutwfc, as you did, but keeping the ecutrho/ecutwfc ratio
>> (rather than the ecutrho variable) constant, to a more or less safe value
>> (e.g. 8).
>>
>> Giovanni
>>
>> > On 23 Oct 2015, at 17:05, adwait mevada <adwait.mevada at gmail.com>
>> wrote:
>> >
>> > Dear All,
>> > I am trying to find optimal ecutwfc for CaMg2.
>> > As a first step i varied ecutwfc from 30-150 but i found that
>> > energy was fluctuating
>> > I cannot decide what to set for ecutrho if my ecutwfc is fluctuating
>> > , what can be the reason for this? any help in this regard is
>> appreciated.
>> >
>> > note : i am not finding ecutwfc for equilibrium volume.
>> >
>> > I am attaching png output of gnuplot for it.
>> >
>> > data for various ecutwfc
>> > ecut    energy                 vol              kpoints  stress  time.
>> > 30     -932.78387473      1314.9516     40   459.00   7m 4.75s
>> > 40     -932.78292968      1314.9516     40   458.52  10m35.69s
>> > 50     -932.78368793      1314.9516     40   458.74  14m22.97s
>> > 60     -932.78388413      1314.9516     40   458.90  17m48.05s
>> > 70     -932.78547210      1314.9516     40   457.91  25m37.98s
>> > 80     -932.78563717      1314.9516     40   459.77  29m17.84s
>> > 90     -932.78419457      1314.9516     40   459.42  35m28.98s
>> > 100     -932.78387315      1314.9516     40   458.78  37m40.76s
>> > 110     -932.78425940      1314.9516     40   458.38  41m34.44s
>> > 120     -932.78459959      1314.9516     40   458.94  52m35.88s
>> > 130     -932.78422725      1314.9516     72   459.24      2h 0m
>> > 140     -932.78394222      1314.9516     72   458.91      2h 3m
>> > 150     -932.78396419      1314.9516     72   458.69      2h30m
>> > my input file is:
>> > C=9
>> > A=5
>> > for ECUT in 30 40 50 60 70 80 90 100 ; do
>> > cat > camg2e$ECUT.in << EOF
>> >  &control
>> >     calculation = 'scf'
>> >     prefix='camg2e$ECUT',
>> >     tstress = .true.
>> >     tprnfor = .true.
>> >  /
>> >  &system
>> >     ibrav=4, a=$A ,c=$C ,nat=12, ntyp=2,
>> >     ecutwfc=$ECUT ! ,ecutrho=480,
>> >     occupations='smearing',smearing="mv",degauss=0.02,
>> >  /
>> >  &electrons
>> >     diagonalization='david'
>> >     mixing_mode = 'plain'
>> >     mixing_beta = 0.7
>> >     conv_thr =  1.0d-8
>> >  /
>> > ATOMIC_SPECIES
>> >  Mg  24.305  Mg.pw91-np-van.UPF
>> >  Ca  40.078  Ca.pw91-nsp-van.UPF
>> > ATOMIC_POSITIONS crystal
>> > Ca      0.3333333   0.6666667   0.0668052
>> > Ca      0.3333333   0.6666667   0.4331948
>> > Ca      0.6666667   0.3333333   0.5668053
>> > Ca      0.6666667   0.3333333   0.9331947
>> > Mg      0.0000000   0.0000000   0.0000000
>> > Mg      0.0000000   0.0000000   0.5000000
>> > Mg      0.3397683   0.1698842   0.2500000
>> > Mg      0.8301158   0.6602317   0.2500000
>> > Mg      0.1698842   0.8301158   0.7500000
>> > Mg      0.8301158   0.1698842   0.2500000
>> > Mg      0.1698842   0.3397683   0.7500000
>> > Mg      0.6602317   0.8301158   0.7500000
>> > K_POINTS automatic
>> > 8 8 4 1 1 1
>> > EOF
>> > mpirun -np 4   pw.x -in camg2e$ECUT.in > camg2e$ECUT.out
>> >    ENERGY=`grep ! camg2e$ECUT.out | cut -b 33-49`
>> >    VOL=`grep volume camg2e$ECUT.out | cut -b 33-45 `
>> >    KP=`grep points= camg2e$ECUT.out | cut -b 25-31`
>> >    TIME=`grep "PWSCF  " camg2e$ECUT.out | cut -b 37-47`
>> >    STRESS=`grep "total   stress" camg2e$ECUT.out | cut -b 72-78`
>> >    FOR=`grep "Total force  " camg2e$ECUT.out`
>> >    echo "$ECUT $ENERGY $ALAT $VOL $KP $STRESS $TIME $FOR"
>> > sleep 60
>> >    echo "$ECUT $ENERGY $ALAT $VOL $KP $STRESS $TIME $FOR" >>
>> camg2r480.dat
>> > done
>> >
>> > Thank you for your help in advance
>> >
>> > --
>> > -Adwait
>> > Ph.D. Student,
>> > Gujarat University,
>> > Gujarat, India.
>> > <camg2ecut.png>_______________________________________________
>> > Pw_forum mailing list
>> > Pw_forum at pwscf.org
>> > http://pwscf.org/mailman/listinfo/pw_forum
>>
>> --
>>
>> Giovanni Cantele, PhD
>> CNR-SPIN
>> c/o Dipartimento di Fisica
>> Universita' di Napoli "Federico II"
>> Complesso Universitario M. S. Angelo - Ed. 6
>> Via Cintia, I-80126, Napoli, Italy
>> e-mail: giovanni.cantele at spin.cnr.it
>> Phone: +39 081 676910
>> Skype contact: giocan74
>>
>> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
>> Web page: http://people.na.infn.it/~cantele
>>
>>
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>


-- 
-Adwait
'I Wonder!...The Empty Cup'

On Fri, Oct 23, 2015 at 9:09 PM, adwait mevada <adwait.mevada at gmail.com>
wrote:

> Dear Giovanni,
> Thanks for the prompt response, I will do as you suggested.
> The above data was obtained without fixing ecutrho to480 (it was
> commented) . I felt that may be a lower kpoint grid or wrong smearing might
> be the source.
> I will do as you suggested and get back to you.
> Thanks again.
> Adwait
> Ph.D. Student,
> Gujarat University,
> Gujarat, India.
> On 23-Oct-2015 8:56 pm, "Giovanni Cantele" <giovanni.cantele at spin.cnr.it>
> wrote:
>
>> one of the problems that you might be running across is that you keep
>> ecutrho fixed. That means that with ecutwfc=30, ecutrho/ecutwfc=16, whereas
>> with ecutwfc=120, the same ratio is 4. The latter is definitely too small
>> for ultrasoft pseudo potentials, that you are including in your
>> calculation. In other words, you might be comparing values of the total
>> energies with different convergence levels with respect to ecutrho, which
>> can be the origin (or a partial explanation) of the oscillations you find.
>>
>> I would try (maybe this will not solve your problem!) to retry the test
>> as a function of ecutwfc, as you did, but keeping the ecutrho/ecutwfc ratio
>> (rather than the ecutrho variable) constant, to a more or less safe value
>> (e.g. 8).
>>
>> Giovanni
>>
>> > On 23 Oct 2015, at 17:05, adwait mevada <adwait.mevada at gmail.com>
>> wrote:
>> >
>> > Dear All,
>> > I am trying to find optimal ecutwfc for CaMg2.
>> > As a first step i varied ecutwfc from 30-150 but i found that
>> > energy was fluctuating
>> > I cannot decide what to set for ecutrho if my ecutwfc is fluctuating
>> > , what can be the reason for this? any help in this regard is
>> appreciated.
>> >
>> > note : i am not finding ecutwfc for equilibrium volume.
>> >
>> > I am attaching png output of gnuplot for it.
>> >
>> > data for various ecutwfc
>> > ecut    energy                 vol              kpoints  stress  time.
>> > 30     -932.78387473      1314.9516     40   459.00   7m 4.75s
>> > 40     -932.78292968      1314.9516     40   458.52  10m35.69s
>> > 50     -932.78368793      1314.9516     40   458.74  14m22.97s
>> > 60     -932.78388413      1314.9516     40   458.90  17m48.05s
>> > 70     -932.78547210      1314.9516     40   457.91  25m37.98s
>> > 80     -932.78563717      1314.9516     40   459.77  29m17.84s
>> > 90     -932.78419457      1314.9516     40   459.42  35m28.98s
>> > 100     -932.78387315      1314.9516     40   458.78  37m40.76s
>> > 110     -932.78425940      1314.9516     40   458.38  41m34.44s
>> > 120     -932.78459959      1314.9516     40   458.94  52m35.88s
>> > 130     -932.78422725      1314.9516     72   459.24      2h 0m
>> > 140     -932.78394222      1314.9516     72   458.91      2h 3m
>> > 150     -932.78396419      1314.9516     72   458.69      2h30m
>> > my input file is:
>> > C=9
>> > A=5
>> > for ECUT in 30 40 50 60 70 80 90 100 ; do
>> > cat > camg2e$ECUT.in << EOF
>> >  &control
>> >     calculation = 'scf'
>> >     prefix='camg2e$ECUT',
>> >     tstress = .true.
>> >     tprnfor = .true.
>> >  /
>> >  &system
>> >     ibrav=4, a=$A ,c=$C ,nat=12, ntyp=2,
>> >     ecutwfc=$ECUT ! ,ecutrho=480,
>> >     occupations='smearing',smearing="mv",degauss=0.02,
>> >  /
>> >  &electrons
>> >     diagonalization='david'
>> >     mixing_mode = 'plain'
>> >     mixing_beta = 0.7
>> >     conv_thr =  1.0d-8
>> >  /
>> > ATOMIC_SPECIES
>> >  Mg  24.305  Mg.pw91-np-van.UPF
>> >  Ca  40.078  Ca.pw91-nsp-van.UPF
>> > ATOMIC_POSITIONS crystal
>> > Ca      0.3333333   0.6666667   0.0668052
>> > Ca      0.3333333   0.6666667   0.4331948
>> > Ca      0.6666667   0.3333333   0.5668053
>> > Ca      0.6666667   0.3333333   0.9331947
>> > Mg      0.0000000   0.0000000   0.0000000
>> > Mg      0.0000000   0.0000000   0.5000000
>> > Mg      0.3397683   0.1698842   0.2500000
>> > Mg      0.8301158   0.6602317   0.2500000
>> > Mg      0.1698842   0.8301158   0.7500000
>> > Mg      0.8301158   0.1698842   0.2500000
>> > Mg      0.1698842   0.3397683   0.7500000
>> > Mg      0.6602317   0.8301158   0.7500000
>> > K_POINTS automatic
>> > 8 8 4 1 1 1
>> > EOF
>> > mpirun -np 4   pw.x -in camg2e$ECUT.in > camg2e$ECUT.out
>> >    ENERGY=`grep ! camg2e$ECUT.out | cut -b 33-49`
>> >    VOL=`grep volume camg2e$ECUT.out | cut -b 33-45 `
>> >    KP=`grep points= camg2e$ECUT.out | cut -b 25-31`
>> >    TIME=`grep "PWSCF  " camg2e$ECUT.out | cut -b 37-47`
>> >    STRESS=`grep "total   stress" camg2e$ECUT.out | cut -b 72-78`
>> >    FOR=`grep "Total force  " camg2e$ECUT.out`
>> >    echo "$ECUT $ENERGY $ALAT $VOL $KP $STRESS $TIME $FOR"
>> > sleep 60
>> >    echo "$ECUT $ENERGY $ALAT $VOL $KP $STRESS $TIME $FOR" >>
>> camg2r480.dat
>> > done
>> >
>> > Thank you for your help in advance
>> >
>> > --
>> > -Adwait
>> > Ph.D. Student,
>> > Gujarat University,
>> > Gujarat, India.
>> > <camg2ecut.png>_______________________________________________
>> > Pw_forum mailing list
>> > Pw_forum at pwscf.org
>> > http://pwscf.org/mailman/listinfo/pw_forum
>>
>> --
>>
>> Giovanni Cantele, PhD
>> CNR-SPIN
>> c/o Dipartimento di Fisica
>> Universita' di Napoli "Federico II"
>> Complesso Universitario M. S. Angelo - Ed. 6
>> Via Cintia, I-80126, Napoli, Italy
>> e-mail: giovanni.cantele at spin.cnr.it
>> Phone: +39 081 676910
>> Skype contact: giocan74
>>
>> ResearcherID: http://www.researcherid.com/rid/A-1951-2009
>> Web page: http://people.na.infn.it/~cantele
>>
>>
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>


-- 
-Adwait
'I Wonder!...The Empty Cup'
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