Oops, I made a mistake. :-( You are totally right.
Thank you for your reply. > > On Jan 15, 2008, at 9:00 AM, Min Seung Kyu wrote: > >> Dear users and developers, >> >> I have a question about eigenfunctions in PWSCF codes. >> >> I looked at PWSCF source files and I found that the 'evc' variable is >> KS eigenvectors in G-space, right? >> >> Because Hamiltonian matrix H(G,G') is hermitian, 'evc' should be real. > > Who said this? > > The eigenvalues of a Hermitean matrix are real, the eigenvectors not > necessarily so. If in addition to being Hermitean the matrix is also real > (which implies it is symmetric), the the eigenvectors CAN BE CHOSEN to be > real. If you feed a real matrix to a complex eigenvalue solver, then the > eigenvectors will most probably come out complex, but can they be easily > converted to real (if needed) by an appropriate choice of phases (again, if > the original matrix is real symmetric, not merely Hermitean) > > Hope this helps > Stefano > >> >> >> When I print out 'evc', however, 'evc' contains imaginary parts. >> >> For example, when I run 'co.rx.in' (example03 folder), I got these values: >> >> DBLE(evc(1:4,1)) 0.186884 0.154551 0.154551 0.142085 >> AIMAG(evc(1:4,1)) 0.000000 0.000000 0.000000 -0.048560 >> DBLE(evc(1:4,2)) -0.024799 -0.021751 -0.021751 -0.068645 >> AIMAG(evc(1:4,2)) 0.000000 0.000000 0.000000 -0.145963 >> DBLE(evc(1:4,3)) 0.000000 0.000000 0.000000 0.000000 >> AIMAG(evc(1:4,3)) 0.000000 -0.005668 0.152298 0.000000 >> DBLE(evc(1:4,4)) 0.000000 0.000000 0.000000 0.000000 >> AIMAG(evc(1:4,4)) 0.000000 -0.152298 -0.005668 0.000000 >> DBLE(evc(1:4,5)) -0.299154 -0.185970 -0.185970 0.011252 >> AIMAG(evc(1:4,5)) 0.000000 0.000000 0.000000 0.168998 >> >> ( I added 'WRITE(*,*) evc(1:4,ibnd)' in 'sum_band.f90'. ) >> >> What is the problem? >> >> Thank you in advance. >> >> Sincerely, Min. >> >> -------------------------------Sig.--------------------------- >> Center for Superfunctional Materials, Department of Chemistry, >> Pohang University of Science and Technology (POSTECH) >> >> Mr. Seung Kyu, Min >> >> Ph.D. Candidate >> >> E-Mail: min0220 at postech.ac.kr >> Tel. : 82-54-279-5858 >> ---------------------------------------------- >> >> >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum > > --- > Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste > [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) > > Please, if possible, don't send me MS Word or PowerPoint attachments > Why? See: http://www.gnu.org/philosophy/no-word-attachments.html > > >
