[Wien] [WIEN]A question on Procedure of Optical calculation

[Laurence Marks]

Many parts of the Wien2k code have been written for clarity rather
than speed; without knowing this part exactly this is probably the
case because it is not a speed-critical part of the code.

On 3/15/07, Jun Jiang <czjiangjun at gmail.com> wrote:
> Dear Professor:
>    I have been confused about the segment of SUBROUTINE OUTSYM(O,nb1,nb2)
> showed below in WIEN2K/SRC_Optic/outmat.f.
>
>       do 772 l=1,iord
>          do ii=1,3
>          o1(ii)=0.0
>          end do
>        do   i=1,3
>        do  ii=1,3
>        o1(i)=o1(i)+opIMAT(ii,i,l)*O(ii)
>        end do
>        end do
>          o2(1)=o2(1)+o1(1)*conjg(o1(1))
>          o2(2)=o2(2)+o1(2)*conjg(o1(2))
>          o2(3)=o2(3)+o1(3)*conjg(o1(3))
>        if (det(l).LT.0) then
>          o2(4)=o2(4)+conjg(o1(2))*o1(1)
>          o2(5)=o2(5)+conjg(o1(3))*o1(1)
>          o2(6)=o2(6)+conjg(o1(3))*o1(2)
>                         else
>          o2(4)=o2(4)+o1(2)*conjg(o1(1))
>          o2(5)=o2(5)+o1(3)*conjg(o1(1))
>          o2(6)=o2(6)+o1(3)*conjg(o1(2))
>        end if
> 772   continue
>
>
>    My First quyestion is that
>        do   i=1,3
>        do  ii=1,3
>        o1(i)=o1(i)+opIMAT(ii,i,l)*O(ii)
>        end do
>        end do
> is obviously a projecting operation.Why is it necessary?
>
>   The second question is, if the first answer is Yes,then Why the cycling
> body denoted by "do 722" must include  the below part:
>
>          o2(1)=o2(1)+o1(1)*conjg(o1(1))
>          o2(2)=o2(2)+o1(2)*conjg(o1(2))
>          o2(3)=o2(3)+o1(3)*conjg(o1(3))
>        if (det(l).LT.0) then
>          o2(4)=o2(4)+conjg(o1(2))*o1(1)
>          o2(5)=o2(5)+conjg(o1(3))*o1(1)
>          o2(6)=o2(6)+conjg(o1(3))*o1(2)
>                         else
>          o2(4)=o2(4)+o1(2)*conjg(o1(1))
>          o2(5)=o2(5)+o1(3)*conjg(o1(1))
>          o2(6)=o2(6)+o1(3)*conjg(o1(2))
>        end if
>
>    Thank you very much!Best regards!
>                                             Sincerely Jun
>
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>


-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
EMM2007 http://ns.crys.ras.ru/EMMM07/