[QE-users] Initial density and wfc guesses from a converged calculation with coarser k mesh

[Yang Liu]

Dear Omar A. Ashour

Thank you very much for your reply!

Best regards

Mr. Yang Liu


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>



>Message: 10



>Date: Tue, 20 Aug 2024 00:54:20 -0700



>From: Omar Ashour <ashour at berkeley.edu>



>To: Quantum ESPRESSO users Forum <users at lists.quantum-espresso.org>



>Subject: Re: [QE-users] Initial density and wfc guesses from a



>	converged	calculation with coarser k mesh



>Message-ID: <9E320D4C-6343-4CA6-8B54-4816866ABA6C at berkeley.edu>



>Content-Type: text/plain; charset=utf-8



>



>As far as I know, this is only supported for the density/potential. The density is stored in real space and can be Fourier transformed to your finer k-grid (Fourier interpolation, more or less). The wave functions, on the other hand, are stored in k-space so there is no straightforward way to change their k-grid. 



>



>Starting your finer grid calculation from the coarse grid density is usually better than starting from scratch, although if your original k-grid was very coarse, the Fourier interpolation to the finer grid will be poor, so your mileage may vary.  



>



>As an aside, I believe VASP does support this using a rudimentary implementation (it just uses the wave functions at the last k-point in the coarser grid for all the extra k-points in the finer grid, which doesn't make much sense to me, especially for incommensurate grids). 



>



>Omar A. Ashour



>UC Berkeley 



>



>> On Aug 20, 2024, at 12:05?AM, Yang Liu <rabbitkiller at 163.com> wrote:



>> 



>> ?Dear QE users



>> 



>> For systems hard to converge, is it possible to use the density and wfcs from a converged calculation with coarser k mesh as initial guesses for refined k mesh calculation?



>> 



>> I tried with "startingpot=file, startingwfc=file", but it seemd that QE accepted the density, but refused the wfcs...



>> 



>> Regards & Thanks



>> 



>> Mr. Yang Liu



>> Fudan Univ., Shanghai, China



>> 



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