You're clearly doing dinner wrong, but you're not providing enough information to say what. I would recommend you study the code and literature and understand how one comes from the other before changing parameters. P.s. alpha is an inverse length.
Regards -- Lorenzo Paulatto On Sat, 11 Jan 2020, 10:50 , <[email protected]> wrote: > Thank you, sir. I have another confusion now. > The long-range dynamical matrix should not change too much if I reset alph > to a larger number, given that it is convergent. > However, I set alph= 2.0d0 and obtain a very different long-range > dynamical matrix. > Where is the problem? > > > > -----原始邮件----- > > 发件人: "Stefano Baroni" <[email protected]> > > 发送时间: 2020-01-11 02:47:40 (星期六) > > 收件人: "Quantum ESPRESSO users Forum" <[email protected]> > > 抄送: > > 主题: Re: [QE-users] phonon dispersion relation from the full IFCs > > > > 1.0 tons is 1000000000 times larger than 1.0 mg. A very large number > indeed! SB > > > > -- > > Stefano Baroni, Trieste -- swift message written and sent on the go > > > > > On 10 Jan 2020, at 18:03, [email protected] wrote: > > > > > > Thank you so much, professor. I really appreciate your scrupulous > reply over and over again. > > > In the QE code(subroutine rgd_dyn) of computing the rigid-ion > (long-range) term, it is commented that > > > "Only the G-space term is implemented: the Ewald parameter alpha must > be large enough to have negligible r-space contribution". > > > But in the following value assignment, alph= 1.0d0, not a very large > number. > > > I think such a value will not make the real-space term vanish in the > Ewald summation. > > > How to understand this? > > > > > > > > >> -----原始邮件----- > > >> 发件人: "Lorenzo Paulatto" <[email protected]> > > >> 发送时间: 2020-01-10 17:19:48 (星期五) > > >> 收件人: [email protected] > > >> 抄送: > > >> 主题: Re: [QE-users] phonon dispersion relation from the full IFCs > > >> > > >>> Is it equivalent to the regular adopted Ewald summation method in > mathematics? > > >> > > >> I think you forgot to attach the paper in question... > > >> > > >> That said, if there is not lo-to splitting, there are no effectiv > > >> charges and no long-range interaction. Than there is no problem doing > > >> Fourier interpolation. > > >> > > >> 2D is a bit special, but the QE code has special techniques to deal > with > > >> 2D phonon interpolation, I think it is explained in Phys. Rev. B 94, > 085415 > > >> > > >> cheers > > >> > > >>> > > >>> With thanks and best regards ! > > >>> Happy New Year ! > > >>> > > >>> > > >>> -- > > >>> Jian-qi Huang > > >>> > > >>> Magnetism and Magnetic Materials Division > > >>> Institute of Metal Research > > >>> Chinese Academy of Sciences > > >>> 72 Wenhua Road, Shenyang 110016, China > > >>> > > >>> email:[email protected] > > >>> > > >>>> -----原始邮件----- > > >>>> 发件人: "Lorenzo Paulatto" <[email protected]> > > >>>> 发送时间: 2020-01-09 03:56:21 (星期四) > > >>>> 收件人: [email protected] > > >>>> 抄送: > > >>>> 主题: Re: [QE-users] phonon dispersion relation from the full IFCs > > >>>> > > >>>>> Thank you for reply, professor. I understand the regular routine > > >>>>> implemented in QE where the long-range contribution is added in > > >>>>> reciprocal space. My point is can I get the correct dynamical > matrix > > >>>>> just by making inverse Fourier transformation of the > full(short+long) > > >>>>> IFCs in a large real space? > > >>>>> > > >>>> > > >>>> The dynamical matrix at Gamma is discontinuity with respect to the > > >>>> points nearby, which would make any Fourier transform impossible to > > >>>> converge. > > >>>> > > >>>> I think you should explain WHY you want to do this, and you may get > some > > >>>> better answer. > > >>>> > > >>>> In practice, if I was obliged at gunpoint, I would replace the > dynamical > > >>>> matrix file at Gamma (typically dyn1) with one computed very close > to > > >>>> Gamma, let's say q=0.001,0,0. Edit the file to trick q2r into > thinking > > >>>> that it was done at exactly Gamma, and see was comes out. > > >>>> > > >>>> If the material has a non-analytic term (i.e. the long range term > > >>>> depends on the direction), this will definitely not work. > Otherwise, you > > >>>> may get something decent. > > >>>> > > >>>> > > >>>> cheers > > >>>> > > >>>> > > >>>> > > >>>> -- > > >>>> Lorenzo Paulatto - Paris > > >>>> _______________________________________________ > > >>>> Quantum ESPRESSO is supported by MaX ( > www.max-centre.eu/quantum-espresso) > > >>>> users mailing list [email protected] > > >>>> https://lists.quantum-espresso.org/mailman/listinfo/users > > >>> _______________________________________________ > > >>> Quantum ESPRESSO is supported by MaX ( > www.max-centre.eu/quantum-espresso) > > >>> users mailing list [email protected] > > >>> https://lists.quantum-espresso.org/mailman/listinfo/users > > >>> > > >> > > >> -- > > >> Lorenzo Paulatto - Paris > > >> _______________________________________________ > > >> Quantum ESPRESSO is supported by MaX ( > www.max-centre.eu/quantum-espresso) > > >> users mailing list [email protected] > > >> https://lists.quantum-espresso.org/mailman/listinfo/users > > > _______________________________________________ > > > Quantum ESPRESSO is supported by MaX ( > www.max-centre.eu/quantum-espresso) > > > users mailing list [email protected] > > > https://lists.quantum-espresso.org/mailman/listinfo/users > > > > _______________________________________________ > > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso > ) > > users mailing list [email protected] > > https://lists.quantum-espresso.org/mailman/listinfo/users > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________ Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) users mailing list [email protected] https://lists.quantum-espresso.org/mailman/listinfo/users
