About the voltage sweep script(ivcurves.py)

[gny1988]

I used the script from http://quantumwise.com/forum/index.php?topic=19.0 to calculate current under a series of voltages. As it said, I put the file ivcurve.py to C:\Program Files\QuantumWise\Virtual NanoLab 2008.10.0\atk\lib\site-packages. But when I calculate current by vnl-2008.10, it said:
Traceback (most recent call last):
  File "c:/docume~1/admini~1/locals~1/temp/tmplq3kcg.nl", line 439, in ?
    ivcurve.runIVcurve (
NameError: name 'ivcurve' is not defined
Terminated Abnormally

Could you help me?

[Anders Blom]

Although in general I wouldn't recommend running such a time-consuming calculation from within VNL (I would export the script, and run it from the command line, ideally on Linux, and in parallel! ), your problem should be easy to solve.

(Changing my previous reply...)

My suspicion is you have left out the line "import ivcurve", or else it would complain that it cannot find this module, but it cannot find the name "ivcurve", which means it was never imported.

[gny1988]

Thank you. That's the problem.

[gny1988]

Another error. Please help me.
  File "c:/docume~1/admini~1/locals~1/temp/tmptugyki.nl", line 447, in ?
    current_number_of_points = 100
  File "C:\Program Files\QuantumWise\Virtual NanoLab 2008.10.0\atk\lib\site-packages\ivcurve.py", line 66, in runIVcurve
    initial_calculation = scf
ATKError: bad allocation
Terminated Abnormally

[Anders Blom]

Out of memory

[gny1988]

My memory is 3G. Is that still enough. Can I change the script to limit the memory?

[zh]

Since the size of the system under study is fixed, the required  memory can be reduced by lowering the calculation accuracy, e.g., smaller cutoff for grid, smaller k-point grid, and so on.