Dear Lorenzo, Thank you so much for pointing out the pw2wannier90.x code. I have seen this code in the wannier90-2.0.1/pwscf/v5.0 folder and it only calculates the overlap for the nearest neighbor k-points (loops over nnb in the compute_mmn subroutine). The one you referred to does not have this limitation. I will give it a try.
Best wishes, Vahid > On Mar 16, 2017, at 5:14 AM, Lorenzo Paulatto > <lorenzo.paula...@impmc.upmc.fr> wrote: > > On Wednesday, March 15, 2017 11:11:54 PM CET Vahid Askarpour wrote: >> I would like to calculate the overlap integral u*_k’(r)u_k(r)d^3r. > > Dear Vahid, > if you want to do it for excercize, go on and do it. > > But, you may be happy to know that this integral is already computed in > several places in the pw code. One in particular is the pw2wannier90.x code > in > particular in PP/src/pw2wannier90.f90 from line 2120 to line 2187 > > (and in general all the compute_mmn subroutine, but it does also a few more > operations and some parts related to ultrasoft pseudopotentials are a bit > difficult to understand) > >> 1. Am I correct in assuming that the above integral is equivalent to the >> sum(C*_k C_k’), where C’s are the coefficients from evc.dat and the sum is >> over igwx (maximum G-vector index) specified in eve.dat? > > No, i I remember correctly the wfcs on files are in G-space. Doing the > product > in G-space is equivalent to doing a convolution in real space. > >> 2. igwx is different for different k-points. One k-point may have igwx=1459 >> while another k-point has igwx=1468. In the above sum, is it correct to >> to use the top 1468 coefficients of the first k-point to calculate the >> overlap >> integral between the two k-points? > > No, because the order is not necessarily the same. Also, because you wouldn't > be doing the product of the two functions but their convolution. > > hth > > > -- > Dr. Lorenzo Paulatto > IdR @ IMPMC -- CNRS & Université Paris 6 > phone: +33 (0)1 442 79822 / skype: paulatz > www: http://www-int.impmc.upmc.fr/~paulatto/ > mail: 23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05 > > _______________________________________________ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum