diag_direct Module Reference

Functions/Subroutines
subroutine	direct (npw, kvec, evec, eval)

Function/Subroutine Documentation

direct()

subroutine diag_direct::direct	(	integer, intent(in)	npw,
		real(8), dimension(3), intent(in)	kvec,
		complex(8), dimension(npw,nbnd), intent(out)	evec,
		real(8), dimension(nbnd), intent(out)	eval
	)

Definition at line 30 of file diag_direct.F90.

    !
    use atm_spec, only : bvec
    use kohn_sham, only : nbnd
    use gvec, only : g_rh, g_wf
    use rho_v, only : vks
    use fftw_wrapper, only : fft_r2g
    !
    integer,intent(in) :: npw
    real(8),intent(in) :: kvec(3)
    complex(8),intent(out) :: evec(npw,nbnd)
    real(8),intent(out) :: eval(nbnd)
    !
    integer :: info, ipw, jpw, lwork, dmill(3)
    real(8) :: rwork(3*npw-2), eval_full(npw), kgv(3)
    complex(8) :: ham(npw,npw), &
    &             VksG(g_rh%nft(1), g_rh%nft(2), g_rh%nft(3))
    complex(8),allocatable :: work(:)
    !
    ! Local potential term
    !
    call fft_r2g(vks, vksg)
    !
    do ipw = 1, npw
       do jpw = 1, npw
          dmill(1:3) = g_wf%mill(1:3,g_wf%map(jpw)) - g_wf%mill(1:3,g_wf%map(ipw))
          dmill(1:3) = modulo(dmill(1:3), g_rh%nft(1:3)) + 1
          ham(jpw,ipw) = vksg(dmill(1), dmill(2), dmill(3))
       end do
    end do
    !
    ! Kinetic energy term
    !
    do ipw = 1, npw
       kgv(1:3) = kvec(1:3) + matmul(bvec(1:3,1:3), dble(g_wf%mill(1:3,g_wf%map(ipw))))
       ham(ipw,ipw) = ham(ipw,ipw) + 0.5d0 * dot_product(kgv,kgv)
    end do
    !
    lwork = -1
    allocate(work(1))
    call zheev('V', 'U', npw, ham, npw, eval_full, work, lwork, rwork, info)
    lwork = nint(dble(work(1)))
    deallocate(work)
    allocate(work(lwork))
    call zheev('V', 'U', npw, ham, npw, eval_full, work, lwork, rwork, info)
    deallocate(work)
    !
    eval(      1:nbnd) = eval_full(1:nbnd)
    evec(1:npw,1:nbnd) = ham(1:npw,1:nbnd)
    !

References atm_spec::bvec, fftw_wrapper::fft_r2g(), gvec::g_rh, gvec::g_wf, kohn_sham::nbnd, and rho_v::vks.

Referenced by scf::kohn_sham_eq().

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