Hi
I've read in the VASP's manual that an option EDIFFG is responsible for the ions relaxation tolerance. It has a meaning of energy tolerance If it's positive and force tolerance in the case of negative values.
Is it somehow possible to set both tolerances?
Krzysztof
energy & force tolerance
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energy & force tolerance
Last edited by kusiu on Fri Jan 25, 2008 1:30 pm, edited 1 time in total.
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energy & force tolerance
the values to choose depend on the problem you want to solve:
--) EDIFFG 0
this depends of the required accuracy of the total energy you need for your investigation, which may vary over several ranges of magnitude: the possible error in energy due to relaxation convergence should be at least one order of magnitude smaller than the requested accuracy of the effect you are investigating: eg, if you need to determine some adsorption energy to an accuracy of meV, EDIFFG should be 1e-4 or 1e-5 at least. (and, correspondingly EDIFF 1e-05 or 1e-06)
--) EDIFFG 0
this depends of the required accuracy of the total energy you need for your investigation, which may vary over several ranges of magnitude: the possible error in energy due to relaxation convergence should be at least one order of magnitude smaller than the requested accuracy of the effect you are investigating: eg, if you need to determine some adsorption energy to an accuracy of meV, EDIFFG should be 1e-4 or 1e-5 at least. (and, correspondingly EDIFF 1e-05 or 1e-06)
Last edited by admin on Mon Jan 28, 2008 9:02 am, edited 1 time in total.
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energy & force tolerance
Thank you for response but it is not what I meant. I mean about setting both tolerances in the same time. For example calculation are stopped when energy difference is less than 1e-05 eV >>AND<< maximal force is less than 0.01 eV/A.
Thank you in advance:
Krzysztof
Thank you in advance:
Krzysztof
Last edited by kusiu on Fri Apr 25, 2008 12:32 pm, edited 1 time in total.
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energy & force tolerance
this is not possible. Only the first entry for each tag in INCAR is taken for input from INCAR, multiple settings are ignored
Last edited by admin on Tue Apr 29, 2008 7:13 am, edited 1 time in total.