mirror of https://gitlab.com/QEF/q-e.git
237 lines
7.8 KiB
Fortran
237 lines
7.8 KiB
Fortran
!
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! Copyright (C) 2001 PWSCF group
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! This file is distributed under the terms of the
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! GNU General Public License. See the file `License'
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! in the root directory of the present distribution,
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! or http://www.gnu.org/copyleft/gpl.txt .
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!
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!-----------------------------------------------------------------------
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subroutine new_ns
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!-----------------------------------------------------------------------
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!
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! This routine computes the new value for ns (the occupation numbers of
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! ortogonalized atomic wfcs).
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! These quantities are defined as follows: ns_{I,s,m1,m2} = \sum_{k,v}
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! f_{kv} <\fi^{at}_{I,m1}|\psi_{k,v,s}><\psi_{k,v,s}|\fi^{at}_{I,m2}>
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!
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#include "machine.h"
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USE io_global, ONLY: stdout
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USE kinds, ONLY: DP
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USE atom, ONLY: lchi, nchi, oc
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USE basis, ONLY: nat, natomwfc, ityp
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USE klist, ONLY: nks
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USE ldaU, ONLY: ns, nsnew, Hubbard_lmax, Hubbard_l, Hubbard_U, &
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Hubbard_alpha, swfcatom, eth, d1, d2, d3
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USE lsda_mod, ONLY: lsda, current_spin, nspin, isk
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USE symme, ONLY: nsym, irt
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USE wvfct, ONLY: nbnd, npw, npwx, igk, wg, gamma_only
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USE wavefunctions_module, ONLY : evc
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USE us, ONLY: newpseudo
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USE gvect, ONLY : gstart
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use io_files
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#ifdef __PARA
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use para
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#endif
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implicit none
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integer :: ik, ibnd, is, i, na, nb, nt, isym, n, counter, m1, m2, &
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m0, m00, l, ldim
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integer, allocatable :: offset (:)
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! counter on k points
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! " " bands
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! " " spins
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! offset of d electrons of atom d
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! in the natomwfc ordering
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real(kind=DP) , allocatable :: nr (:,:,:,:)
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real(kind=DP) :: t0, scnds
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! cpu time spent
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real(kind=DP), external :: DDOT
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complex(kind=DP) :: ZDOTC
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complex(kind=DP) , allocatable :: proj(:,:)
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real(kind=DP) :: psum
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t0 = scnds ()
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ldim = 2 * Hubbard_lmax + 1
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allocate( offset(nat), proj(natomwfc,nbnd), nr(ldim,ldim,nspin,nat) )
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!
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! D_Sl for l=1, l=2 and l=3 are already initialized, for l=0 D_S0 is 1
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!
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counter = 0
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do na = 1, nat
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nt = ityp (na)
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do n = 1, nchi (nt)
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if (oc (n, nt) .gt.0.d0.or..not.newpseudo (nt) ) then
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l = lchi (n, nt)
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if (l.eq.Hubbard_l(nt)) offset (na) = counter
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counter = counter + 2 * l + 1
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endif
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enddo
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enddo
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if (counter.ne.natomwfc) call errore ('new_ns', 'nstart<>counter', 1)
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nr (:,:,:,:) = 0.d0
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nsnew (:,:,:,:) = 0.d0
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!
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! we start a loop on k points
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!
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if (nks.gt.1) rewind (iunigk)
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do ik = 1, nks
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if (lsda) current_spin = isk(ik)
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if (nks.gt.1) read (iunigk) npw, igk
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if (nks.gt.1) call davcio (evc, nwordwfc, iunwfc, ik, - 1)
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call davcio (swfcatom, nwordatwfc, iunat, ik, - 1)
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!
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! make the projection
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!
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do ibnd = 1, nbnd
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do i = 1, natomwfc
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if ( gamma_only ) then
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proj (i, ibnd) = 2.d0 * &
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DDOT(2*npw, swfcatom (1, i), 1, evc (1, ibnd), 1)
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if (gstart.eq.2) proj (i, ibnd) = proj (i, ibnd) - &
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swfcatom (1, i) * evc (1, ibnd)
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else
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proj (i, ibnd) = ZDOTC (npw, swfcatom (1, i), 1, evc (1, ibnd), 1)
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endif
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enddo
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enddo
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#ifdef __PARA
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call reduce (2 * natomwfc * nbnd, proj)
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#endif
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!
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! compute the occupation numbers (the quantities n(m1,m2)) of the
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! atomic orbitals
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!
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do na = 1, nat
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nt = ityp (na)
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if (Hubbard_U(nt).ne.0.d0 .or. Hubbard_alpha(nt).ne.0.d0) then
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do m1 = 1, 2 * Hubbard_l(nt) + 1
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do m2 = m1, 2 * Hubbard_l(nt) + 1
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do ibnd = 1, nbnd
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nr(m1,m2,current_spin,na) = nr(m1,m2,current_spin,na) + &
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wg(ibnd,ik) * DREAL( proj(offset(na)+m2,ibnd) * &
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conjg(proj(offset(na)+m1,ibnd)) )
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enddo
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enddo
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enddo
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endif
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enddo
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! on k-points
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enddo
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#ifdef __PARA
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call poolreduce (ldim * ldim * nspin * nat , nr)
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#endif
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if (nspin.eq.1) nr = 0.5d0 * nr
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!
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! impose hermiticity of n_{m1,m2}
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!
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do na = 1, nat
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nt = ityp(na)
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do is = 1, nspin
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do m1 = 1, 2 * Hubbard_l(nt) + 1
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do m2 = m1 + 1, 2 * Hubbard_l(nt) + 1
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nr (m2, m1, is, na) = nr (m1, m2, is, na)
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enddo
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enddo
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enddo
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enddo
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! symmetryze the quantities nr -> nsnew
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do na = 1, nat
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nt = ityp (na)
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if (Hubbard_U(nt).ne.0.d0 .or. Hubbard_alpha(nt).ne.0.d0) then
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do is = 1, nspin
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do m1 = 1, 2 * Hubbard_l(nt) + 1
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do m2 = 1, 2 * Hubbard_l(nt) + 1
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do isym = 1, nsym
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nb = irt (isym, na)
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do m0 = 1, 2 * Hubbard_l(nt) + 1
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do m00 = 1, 2 * Hubbard_l(nt) + 1
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if (Hubbard_l(nt).eq.0) then
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nsnew(m1,m2,is,na) = nsnew(m1,m2,is,na) + &
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nr(m0,m00,is,nb) / nsym
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else if (Hubbard_l(nt).eq.1) then
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nsnew(m1,m2,is,na) = nsnew(m1,m2,is,na) + &
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d1(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
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d1(m00,m2,isym) / nsym
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else if (Hubbard_l(nt).eq.2) then
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nsnew(m1,m2,is,na) = nsnew(m1,m2,is,na) + &
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d2(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
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d2(m00,m2,isym) / nsym
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else if (Hubbard_l(nt).eq.3) then
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nsnew(m1,m2,is,na) = nsnew(m1,m2,is,na) + &
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d3(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
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d3(m00,m2,isym) / nsym
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else
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call errore ('new_ns', &
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'angular momentum not implemented', &
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abs(Hubbard_l(nt)) )
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end if
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enddo
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enddo
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enddo
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enddo
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enddo
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enddo
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endif
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enddo
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! Now we make the matrix ns(m1,m2) strictly hermitean
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do na = 1, nat
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nt = ityp (na)
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if (Hubbard_U(nt).ne.0.d0 .or. Hubbard_alpha(nt).ne.0.d0) then
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do is = 1, nspin
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do m1 = 1, 2 * Hubbard_l(nt) + 1
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do m2 = m1, 2 * Hubbard_l(nt) + 1
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psum = abs ( nsnew(m1,m2,is,na) - nsnew(m1,m2,is,na) )
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if (psum.gt.1.d-10) then
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WRITE( stdout, * ) na, is, m1, m2
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WRITE( stdout, * ) nsnew (m1, m2, is, na)
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WRITE( stdout, * ) nsnew (m2, m1, is, na)
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call errore ('new_ns', 'non hermitean matrix', 1)
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else
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nsnew(m1,m2,is,na) = 0.5d0 * (nsnew(m1,m2,is,na) + &
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nsnew(m2,m1,is,na) )
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nsnew(m2,m1,is,na) = nsnew(m1,m2,is,na)
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endif
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enddo
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enddo
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enddo
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endif
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enddo
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!
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! Now the contribution to the total energy is computed. The corrections
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! needed to obtain a variational expression are already included
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!
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eth = 0.d0
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do na = 1, nat
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nt = ityp (na)
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if (Hubbard_U(nt).ne.0.d0 .or. Hubbard_alpha(nt).ne.0.d0) then
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do is = 1, nspin
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do m1 = 1, 2 * Hubbard_l(nt) + 1
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do m2 = 1, 2 * Hubbard_l(nt) + 1
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eth = eth + Hubbard_U(nt) * nsnew(m1,m2,is,na) * &
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(ns(m2,m1,is,na) - nsnew(m2,m1,is,na) * 0.5d0)
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enddo
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enddo
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enddo
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endif
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enddo
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deallocate ( offset, proj, nr )
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if (nspin.eq.1) eth = 2.d0 * eth
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return
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end subroutine new_ns
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