can we start simulation from middle??

[Sarvesh Agarwal]

Is there any way to restart a simulation from middle, i mean if anyhow our simulation gets stop due to any reason, hence, to save time can we restart the simulation from the point where it was stopped.

[kstokbro]

see the tutorial:
http://www.quantumwise.com/publications/tutorials/mini-tutorials/142

[kstokbro]

note, this tutorial is to restart the scf iteration where it was stopped, it you have a loop in your python input file, forinstance for doing I-V, you will need to manually change the input file to start at the right loop point.

[sergio]

Hi,

In atk 12.8, to restart a stopped calculation, we can use:

configuration = nlread("checkpointfile.nc")[0]
configuration.update(force_restart=True)
nlsave("file.nc",configuration)

given in the mini-tutorials.

In atk 11.2.3 "force_restart" is not recognized. How can we employ this script in atk 11.2.3?

Thanks,

[Anders Blom]

That's why we introduced that keyword, to make it easier I think it's possible to use "initial_state" instead in 11.2. So, you take your original script, add

Code: python

checkpoint =  = nlread("checkpointfile.nc")[0]

to the top, and then add the keyword

Code: python

initial_state = checkpoint

to "setCalculator".

[sergio]

Thanks for your reply.  However when I do what you have written, even if I have already tem. checkpointfile, I have enecountered with the following in the first statement of the output file:

"Warning:
  The provided initial state parameter has no pre-calculated data.
  Proceeding without setting an initial state."

That is, it starts from the left electrode calculation.

Is there anything wrong?

Thanks,

[Anders Blom]

It means the checkpoint file doesn't contain what is required... Hard to say why, you may want to inspect its contents and file size to determine this. It also matters where the calculation was interrupted, if it happened in the equivalent bulk part, it will not work - but then you haven't lost that much anyway, you can just as well rerun.