QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: sathyajit on June 4, 2015, 16:08

Title: restarting from saved checkpoint
Post by: sathyajit on June 4, 2015, 16:08

Hi,

I am doing a transmission spectrum calculation with 2 metal electrodes and a central region of semiconductor. I see that the checkpoint .nc file is saved only till the point where Left and Right electrodes are converged. Is there a way to save checkpoints in between the central region convergence ?

Regards
Sathyajit

Title: Re: restarting from saved checkpoint
Post by: Jess Wellendorff on June 5, 2015, 08:30

Dear Sathysjit,

In short: no, you can not make ATK save the converged electrodes to the nc file before converging the full device.

If you look in your script, the "update()" function call is the one that instructs ATK to compute the ground state electronic structure of the device. This is followed by the "nlsave" call, which writes the converged ground state to nc file. So the full device calculation must converge before it is written to nc.

Code

device_configuration.setCalculator(calculator)
nlprint(device_configuration)
device_configuration.update()
nlsave('myfile.nc', device_configuration)

Regards,
Jess

Title: Re: restarting from saved checkpoint
Post by: Umberto Martinez on June 5, 2015, 08:56

These two links can also be helpful:

http://quantumwise.com/publications/tutorials/item/116-reusing-electrodes
http://quantumwise.com/publications/tutorials/item/502-restarting-stopped-calculations