[Pw_forum] complex band
Manoj Srivastava
manoj at phys.ufl.edu
Thu Nov 27 00:26:11 CET 2008
Dear Alexander, PWSCF users and developers,
I have a technical question in one of the subroutines used to calculate
complex band. The subroutine 'init_gper.f90' under PWCOND directory is
used to calculate number of G perpendicular vectors within the energy
cutoff by using [k_{\perp}+G_{\perp}]^2.le.E_{cut}. I understand the
counting of Gper, but i dont understand how do they construct the Gper
vectors. For example what is 'ngpsh'? It is defined as 'no. of shells for
G', but i really dont understand what this is. I dont understand after
line 50 of the code in init_gper.f90. Mainly what does the following
piece of code do
do i=1,nrx
do j=1,nry
icount=0
do iw=1, ngpsh
if (abs(norm2-gnorm2(iw)).gt.eps) then
icount=icount+1
else
nshell(i,j)=iw
endif
enddo
if (icount.eq.ngpsh) then
ngpsh=ngpsh+1
gnorm2(ngpsh)=norm2
nshell(i,j)=ngpsh
endif
endif
enddo
enddo
I understand it is not a good way of asking question, but I am completely
lost. Any help will be appreciated.
Regards,
Manoj
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