The Fourier-Bessel transformation was tested once upon a time, but it had a funny behavior sometimes and it was finally abandoned; the Fourier transforms of the radial parts are done in a rather dumb way, by computing the integrals \beta_l(q_i) = \int 4\pi r^2 \beta(r) j_l(q_ir) dr on a uniform grid of q_i, interpolating them (optionally with splines, with a simple interpolation formula otherwise) for the required q=|k+G|
Paolo On Fri, Jun 17, 2016 at 1:49 PM, Ryky Nelson <[email protected]> wrote: > Hello Paolo, > > I just want to know what kind of algorithm (method) used to > 3D-Fourier-transform and interpolate the projectors (beta functions). Does > it use the Fourier-Bessel transformation and Spline interpolation, > respectively? And thank you for the information of the subroutines. > > Ryky Nelson > Institut für Anorganische Chemie > RWTH Aachen University > > On Fri, Jun 17, 2016 at 12:20 PM, Paolo Giannozzi <[email protected]> > wrote: >> >> I am not sure I understand your questions. Projectors, aka "beta >> functions", are computed in reciprocal space (variable "vkb") by >> routine "init_us_2", using interpolation from a table computed by >> routine "init_us_1" >> >> Paolo >> >> On Thu, Jun 16, 2016 at 2:33 PM, Ryky Nelson <[email protected]> >> wrote: >> > Hello QE users and developers, >> > >> > in the PAW scheme, there's a step to calculate wave-function characters >> > at a >> > given k-point, i.e. <p_tilde (k) | psi_tilde(k)>. However, projectors >> > (p_tilde) are given in real-space in UPF files whereas the smooth >> > wave-functions are expanded in G(reciprocal)-space. Could someone tell >> > me >> > how and in what subroutine(s) this wave-function character is calculated >> > in >> > Espresso? Also, is there any interpolation method used in this >> > calculation? >> > >> > Thank you! >> > >> > Ryky Nelson >> > Institut für Anorganische Chemie >> > RWTH Aachen University >> > >> > _______________________________________________ >> > Pw_forum mailing list >> > [email protected] >> > http://pwscf.org/mailman/listinfo/pw_forum >> >> >> >> -- >> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, >> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy >> Phone +39-0432-558216, fax +39-0432-558222 >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
