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gfortran -O3 -march=native -fopenmp -DUSEOMP -ffree-line-length-0 -cpp -DXS -DISO -DLIBXC -I
./finclude -c -I../../src ../../src/mod_potential_and_density.F90
../../src/mod_potential_and_density.F90:11:10:

Use modinput
1
Fatal Error: Can't open module file ‘modinput.mod’ for reading at (1): No such file or directo
ry
compilation terminated.
Makefile.mkmf:961: recipe for target 'mod_potential_and_density.o' failed
make[3]: *** [mod_potential_and_density.o] Error 1
m

vorwerkcvorwerkc 02 Jun 2017 12:38
in discussion Forum / Support Questions » sh 1: bad substitution

Dear all,
thank you for bringing the error message to our attention.
It seems that the error depends on the architecture you use. Could you provide information on the gfortran compiler version and the version of your default shell?

Best regards
Christian Vorwerk
(exciting team)

by vorwerkcvorwerkc, 02 Jun 2017 12:38

Hello everyone,

I was doing some calculations with GGA_PBE_SOL and, when I added spin-orbit coupling I got the message "Warning(init0): GGA inconsistent with non-collinear magnetism". Which kind of error should I expect if I still use GGA for the calculations? Is there any case where I can ignore this warning or do I need to change to L(S)DA to get any correct observable?

Thanks!

GGA inconsistent with non-collinear magnetism by Antônio Manesco (guest), 02 Jun 2017 11:35
Hala (guest) 31 May 2017 02:12
in discussion Forum / Support Questions » sh 1: bad substitution

I have the same problem. I used the above mentioned way to solve the problem (bash xxx.sh) but it did not work.

Anybody can help in solving this problem please answer the post

Thanks

by Hala (guest), 31 May 2017 02:12
DmitriiNabokDmitriiNabok 27 May 2017 09:48
in discussion Forum / Support Questions » shg energies

Hi Mike,

Ok, in this case my guess would be to check the total number of basis functions (the maximum number of the available states). This info is printed in INFO.OUT or simpler to find it in KPOINTS.OUT (last column). An alternative way to look at EIGVAL.OUT file and see the number of printed eigenenergies and their values.
If you discover that instead 5000 states EIGVAL.OUT contains only 1000, you should recalculate your system using a higher value of rgkmax (add more augmented plane-waves) and check if you reach a wanted upper energy.

Well, you could also send me your input file so I'll not guess about the reason :-)

Best,
Dmitri

by DmitriiNabokDmitriiNabok, 27 May 2017 09:48
Mike Mitchell (guest) 26 May 2017 14:38
in discussion Forum / Support Questions » shg energies

Hi Dmitri:
I did try that, wmax=1.0 and asked for 5000 states… Still no go…
Any other ideas?

—Mike

by Mike Mitchell (guest), 26 May 2017 14:38

Hi Mike,

Did you try to increase wmax value in addition to the number of empty states?

Best regards,
Dmitri

Re: shg energies by DmitriiNabokDmitriiNabok, 24 May 2017 07:29
Luan Guo (guest) 23 May 2017 20:08
in discussion Forum / Support Questions » sh 1: bad substitution

I got the problem too!
I search on-line, it's says that,we should run it with

bash xxx.sh

sth like this, I didn't try.
Luan Guo

by Luan Guo (guest), 23 May 2017 20:08
shg energies
Mike Mitchell (guest) 23 May 2017 14:37
in discussion Forum / Support Questions » shg energies

Hello all:
Thanks for the great code!
I was wondering how I would specify the emax variable for the shg calculations? I'm interested in looking at photon energies near the absorption edge. I tried asking for more empty states (nempty) but still only get energies up to 25eV.
Thanks!

—Mike

shg energies by Mike Mitchell (guest), 23 May 2017 14:37
Bad substitution
Hala (guest) 11 May 2017 21:07
in discussion Forum / Support Questions » Bad substitution

when I run EXECUTE-single.sh I get sh:1 bad substitution
I am working on Ubuntu 14.04

Bad substitution by Hala (guest), 11 May 2017 21:07
Pavel (guest) 11 May 2017 15:02
in discussion Forum / Support Questions » c-Si GW+BSE

Great, the taskname="skip" was what I was looking for, would be nice if this could be documented in the input reference

Anyway thanks a lot for all the help, hopefully I will not bother for some time now…

by Pavel (guest), 11 May 2017 15:02
DmitriiNabokDmitriiNabok 11 May 2017 13:50
in discussion Forum / Support Questions » c-Si GW+BSE

Currently in exciting, one can use GW qp-energies as an input for BSE only.
So surely, you can initialize new BSE calculations on top of the same GW output. For this you need only to copy EVALQP.OUT (binary) and to have the <gw> element present in input.xml. To disable running GW, one needs simply replace: taskname="skip"

Regarding the list of "know issues", we have it internally and try so solve it as soon as possible ;-)

by DmitriiNabokDmitriiNabok, 11 May 2017 13:50
Pavel (guest) 11 May 2017 13:22
in discussion Forum / Support Questions » c-Si GW+BSE

Thanks for the info,
I'll try to do it by hand it is not a big deal, however I will have to think more about this how to select the best offsets so that the combined sampling of the BZ is reasonable. I may need to read something more on the double-grid technique, any pointers?

However this brings me back to a question from the third post:
Is is possible to do xc calculations on top of existing GW without redoing it?
e.g. something equivalent to do="skip" parameter for the groundstate?
This is now even more urgent if I'm about to do the multiple xc calculation on top of single GW calc.

BTW is there some list of known issues or something similar?
I looked at the github but the repo there seems to be quite outdated.

by Pavel (guest), 11 May 2017 13:22
DmitriiNabokDmitriiNabok 11 May 2017 08:33
in discussion Forum / Support Questions » c-Si GW+BSE

Dear Pavel,

I'm glad to hear that you have no problems with GW part :-)
Regarding the BSE part… Unfortunately, as we have recently discovered, there is a problem in the implemented version of the double-grid technique.
However, you can still proceed with this technique by doing it manually.
For this, e.g., to double k-grid, you should choose 4 k-point offsets and perform 4 corresponding BSE calculations. And in the end to make the spectrum averaging. We did it for another system and I wonder to repeat for Si.

Best regards,
Dmitrii

by DmitriiNabokDmitriiNabok, 11 May 2017 08:33
Pavel (guest) 11 May 2017 08:22
in discussion Forum / Support Questions » c-Si GW+BSE

Dear Dmitrii,
thanks for the advice, I played little with the other parameters and there is not much change, however with all those improvements with the nbands and others combined, the direct Gamma-Gamma gap is now 3.24eV, which should be quite comparable with experiments…

Now, looking at the comparison of my BSE spectra with 0K exp data the first peak position is only about 0.1eV below the experimental one, the second peak maximum is little bit worse, bit over 0.2 eV below the experimental, however I'm quite happy with this ;-)

The remaining discrepancies could be caused by the 10x10x10 grid in the BSE (since it still seems not so well converged).
My last remaining problem is with the double-grid technique for the xs. Can the ngridksub parameter just be added into the calculations as is or are there some other changes needed? E.g. if I add ngridksub="2 2 2" to the BSE element in the example input file from the first post, the calculations seem to run fine (looking at the INFOXS the BSE calculation is repeated three time), however the resulting averaged dielectric function is wrong. It actually looks more like it should be with the RPA or IP bsetype, any ideas what I did wrong or what should I do to fix this? (even adding ngridksub="2 2 2" into the example LiF calculation produces completely bad results…)

Anyway thank a lot for all the help.

by Pavel (guest), 11 May 2017 08:22
DmitriiNabokDmitriiNabok 10 May 2017 18:25
in discussion Forum / Support Questions » c-Si GW+BSE

Dear Pavel,

Do I understand correctly, that your major concern is to reproduce the experimental band gap in Si?
There are many things to mention prior going into technical details.
What is the value you're aiming at? There are many experimental as well as the theoretical results.
You can find in the literature the hole spectrum of G0W0 band gaps depending on the input structure and implementation.

Correct me if I'm wrong, the value you have reported before is the indirect band gap between X1(0,0.3,0.3)(CBM) [in the reciprocal unitcell units] and Gamma(VBM). This quite close to the X* point. However, since you're doing optics, I'd rather recommend you to look at the convergence of the direct band gap instead.
Before playing with the basis sets and fighting for the ultimate numerical convergence, I'd still recommend you to check the parameters which remained hidden (default). What about to expand the <gw> element:

<gw
taskname="g0w0"
ngridq="6 6 6"
nempty="300"
ibgw="1" nbgw="22"
>
<mixbasis
lmaxmb="3"
epsmb="1.0d-4"
gmb="1.0d0"
></mixbasis>
<barecoul
barcevtol="0.1"
></barecoul>
<freqgrid
nomeg="32"
freqmax="1.d0"
></freqgrid>
<selfenergy
actype="pade"
><selfenergy/>
<scrcoul
scrtype="rpa"
></scrcoul>
</gw>

The grid 6x6x6 should already be quite good, especially for tests. The product basis parameter could be an issue for some materials, but not in 'simple' Si. The number of frequencies is rather important and should not be overlooked.
In the posts above, you were correctly mentioning that the total number of the available empty states is restricted by the chosen in <groundstate> rgkmax parameter (Gmax). This number you should be able to see in KPOINT.OUT file, last column. So to reach high values of nempty, one has to modify rgkmax and recalculate groundstate cycle.
Thus, in your case for rgkmax=8, 300 empty states should already exceed the maximum number of the augmented plane waves.

You have also correctly mentioned that to reach numerically converged results it's often not enough to operate with the well converged groundstate (starting-point dependence), the number of states and the size of k/q-grids. One should extra take care about the complimentary basis-set incompleteness error. Similarly to pseudopotential method, for the excited state calculations one needs to employ specially optimized LAPW+LO basis (choose another species file). However, it has been shown a few times, that the basis set incompleteness is rather small for Si. So the reason for the inconsistent results one should look somewhere else.

The my suggestion is to modify the gw element and repeat calculations. The values you should ~1.21 eV [Gamma-X] and 3.21 eV [Gamma-Gamma] (depends on the lattice parameters).

Please let me know about your findings.
With best regards,
D. Nabok
(the exciting developers team)

by DmitriiNabokDmitriiNabok, 10 May 2017 18:25
Pavel (guest) 10 May 2017 15:21
in discussion Forum / Support Questions » c-Si GW+BSE

So actually to follow up on the problem, increasing the number of empty states does not lead to much better QP energies:
nempty=100 : GAP 1.2150 eV
nempty=200 : GAP 1.2441 eV
nempty=300 : GAP 1.2537 eV
nempty=500 : GAP 1.2607 eV

by Pavel (guest), 10 May 2017 15:21
Pavel (guest) 09 May 2017 12:03
in discussion Forum / Support Questions » c-Si GW+BSE

Sorry, I pressed enter too early and the the last section of the previous posts is messed up, it should be:

3) I also had a look at the article "D. Nabok, A. Gulans, and C. Draxl, "Accurate all-electron G0W0 quasiparticle energies employing the full-potential augmented plane-wave method", Phys. Rev. B 94, 035118 (2016).", and the crucial stuff seems to be (beside the number of empty bands) also the usage of local orbitals for unoccupied states and the maximum angular momentum for such orbitals, how can I select this in the calculations?

by Pavel (guest), 09 May 2017 12:03
Pavel (guest) 09 May 2017 11:55
in discussion Forum / Support Questions » c-Si GW+BSE

Dear Caterina,

thanks for the advice, I'm trying it now, just few more questions.

1) The nempty parameter (in both groundstate and gw) seems to be truncated somehow, to the value of "Minimal number of LAPW states"
how can I get more LAPW states, do I need to increase the basis (rgkmax) or something else?

2) Is is possible to do xc calculations on top of existing GW without redoing it?
e.g. something equivalent to do="skip" parameter for the groundstate?

3) I did some reading of the
I also had a look at the article "D. Nabok, A. Gulans, and C. Draxl, "Accurate all-electron G0W0 quasiparticle energies employing the full-potential augmented plane-wave method", Phys. Rev. B 94, 035118 (2016)." which also article, and the crucial stuff seems to be (beside the number of occupied bands) also the usage of local orbitals for unoccupied states and the maximum angular momentum for such orbitals, how can I select this in the calculations?

by Pavel (guest), 09 May 2017 11:55

Dear Pavel,

I think your problem is related to the small number of empty states that you are including in the GW calculation. 100 is really not enough for comparing your results with published data. The exact number of empty states needs to be converged carefully and depends on the specific system, but typically several hundreds of states are needed to achieve reliable results. I suggest you to focus on the GW step since indeed the parameters for the solution of the BSE seem reasonable to me.

I hope this helps!

Best regards,
Caterina Cocchi
(exciting team)

Re: c-Si GW+BSE by Caterina CocchiCaterina Cocchi, 09 May 2017 11:02
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