Messages

16

General Questions and Answers / Re: OptimizationDevice Geometry

« on: January 10, 2020, 08:49 »

This means that the Poisson solver did not converge. You could try changing it, f.ex. to the Parallel Conjugate Gradient solver or increasing the mesh cutoff. You should also check that your gate and dielectric setup (if present) is reasonable.

17

General Questions and Answers / Re: Heterostructure Band Gap calculation using MGGA

« on: September 9, 2019, 09:29 »

It is described with an example on the manual page here: https://docs.quantumatk.com/manual/Types/ExchangeCorrelation/ExchangeCorrelation.html

18

General Questions and Answers / Re: Parallelization in ATK 13.8

« on: May 21, 2019, 08:54 »

The 13.8 version is no longer supported. I suggest you take a look at the newest P-2019.03 version and the many improvements that have been made since 13.8.

19

General Questions and Answers / Re: Phonon Dispersion Spectrum of GNR (Geometry optimization and mode separation)

« on: April 29, 2019, 09:28 »

This happens because you optimize the structure after calculating the Dynamical matrix and before calculating the phonon bandstructure. So what you do is this:

1. Calculate the dynamical matrix for your structure
2. Optimize, i.e. change the structure
3. Calculate the phonon bandstructure based on your DM and configuration, which no longer match.

You need to optimize the structure first, otherwise the rest does not really make sense.

20

General Questions and Answers / Re: NLValueError

« on: March 27, 2019, 10:22 »

You are right that you should make sure to use consistent exchange-correlation functionals, not LDA for one and GGA for the other. However, it  is only the indirect reason for the error you see. Because you change the exchange-correlation type, you will get different default basis sets because you have not explicitly defined them, and this mismatch causes the error.

The important lines in the tutorial scripts (para.py and angles.py) are these:

para.py - lines 116-123

Code

basis_set = [
    LDABasis.Carbon_SingleZetaPolarized,
    ]

#----------------------------------------
# Exchange-Correlation
#----------------------------------------
exchange_correlation = LSDA.PZ

angles.py - lines 16-20

Code

    calculator = device_configuration.calculator()
    calculator = calculator(
        exchange_correlation=NCLDA.PZ,
        iteration_control_parameters=iteration_control_parameters,
    )

Note how the basis set is explicitly defined in the first, spin-polarized, calculation, which is then read in and used as the starting point for defining the noncollinear one. This ensures that the calculation parameters are consistent.

P.S. Please attach your scripts instead of including the full text in the post. In that way, it will be much easier to read for everybody.

21

General Questions and Answers / Re: NLValueError

« on: March 26, 2019, 10:33 »

It seems that you are using different basis sets for the initial and the Spin-Orbit calculations. If you attach both of the scripts I can make a suggestion that should solve the issue.

22

General Questions and Answers / Re: How to solve this question?

« on: March 21, 2019, 10:32 »

It looks like the computing node(s) had problems with the connection to the license server. The final error could be a result of those connection problems, or it could be running out of memory.

23

General Questions and Answers / Re: why those add-on-plugin disappear in the lastes 2019-03 version

« on: March 20, 2019, 14:49 »

The Twister plugin is not shipped with the installer, but must be downloaded from the AddOn manager. It is contained in the FunWithGraphene AddOn.

24

General Questions and Answers / Re: in my working flow, the iv calculation is for unrelax or relaxed configuration

« on: March 14, 2019, 16:31 »

If you do it like you show, without any modifications, it will be the unrelaxed configuration. Study objects are not designed to be used sequentially in the same script.

However, it is easy to use the relaxed configuration instead. Just insert this line between the two study objects:

device_configuration = optimize_device_configuration.result()

25

General Questions and Answers / Re: Output the Electron Phonon Scattering Rate in Graphene Nanoribbons

« on: March 7, 2019, 09:30 »

There is a typo in the line where the energies are defined, where there is a trailing comma, which should not be there. If you remove it, it works. I will make sure to fix the script.

Note that you should also change the file ending to hdf5, but QuantumATK will automatically do that in the current version.

26

General Questions and Answers / Re: Output the Electron Phonon Scattering Rate in Graphene Nanoribbons

« on: March 7, 2019, 09:06 »

You can use the built-in methods to extract the matrix elements, see the manual page for details: https://docs.quantumatk.com/manual/Types/ElectronPhononCoupling/ElectronPhononCoupling.html
Note that we do not recommend, or support, accessing the hdf5 files 3rd-party software.

I will look into the other issue.

27

General Questions and Answers / Re: Output the Electron Phonon Scattering Rate in Graphene Nanoribbons

« on: March 1, 2019, 08:48 »

Sounds like you need the method .inverseRelaxationTime(), which can be invoked in a script - see the manual page for more details: https://docs.quantumatk.com/manual/Types/Mobility/Mobility.html

Does it look like the properties you need?

28

General Questions and Answers / Re: how to use less memory but performance did not change much

« on: February 27, 2019, 15:37 »

It will depend on the details of your device, so it is hard to give advice without seeing the script.

However, one thing you can do is to make sure threading is enabled. It will allow you to re-gain some of the performance that is lost when you reduce the number of processes. Also, make sure you distribute the processes equally on the node, to ensure that you can utilize the available memory efficiently. How to do this in practice depends on the hardware and queuing system, and cannot be done from inside QuantumATK.

29

Installation and License Questions / Re: any one has the same err while connect to license server？

« on: February 27, 2019, 15:32 »

The port restrictions are mentioned elsewhere in the installation guide: https://docs.quantumatk.com/guides/license_server_linux.html#modify-the-server-line

I believe they apply to both the primary and secondary ports.

30

Installation and License Questions / Re: any one has the same err while connect to license server？

« on: February 27, 2019, 11:34 »

You can probably solve the problem by the approach mentioned here: https://docs.quantumatk.com/guides/license_server_linux.html#optional-adding-a-second-port

If not, we will need more information, and as Petr wrote, technical and license issues are better handled using the support e-mail.