FFT grid and cutoff energy.
Posted: Tue May 31, 2011 5:05 pm
Hi all,
I've learned that, for all of the PW based DFT codes, such as, VASP/PWscf/Abinit/CASTEP, the FFT grid is generated based on the cutoff energy. So if we have tested the convergence total energy vs cutoff energy, then the FFT grid used for our calcultions should also be OK based on the selected cutoff energy. In other words, it is unnecessary to do a independent FFT grid convergence test. Am I right?
Regards.
--
Hongsheng Zhao <zhaohscas@yahoo.com.cn>
School of Physics and Electrical Information Science,
Ningxia University, Yinchuan 750021, China
I've learned that, for all of the PW based DFT codes, such as, VASP/PWscf/Abinit/CASTEP, the FFT grid is generated based on the cutoff energy. So if we have tested the convergence total energy vs cutoff energy, then the FFT grid used for our calcultions should also be OK based on the selected cutoff energy. In other words, it is unnecessary to do a independent FFT grid convergence test. Am I right?
Regards.
--
Hongsheng Zhao <zhaohscas@yahoo.com.cn>
School of Physics and Electrical Information Science,
Ningxia University, Yinchuan 750021, China