quantum-espresso/PW/new_ns.f90

212 lines
7.1 KiB
Fortran

!
! Copyright (C) 2001-2007 Quantum ESPRESSO group
! This file is distributed under the terms of the
! GNU General Public License. See the file `License'
! in the root directory of the present distribution,
! or http://www.gnu.org/copyleft/gpl.txt .
!
!
!-----------------------------------------------------------------------
SUBROUTINE new_ns(ns)
!-----------------------------------------------------------------------
!
! This routine computes the new value for ns (the occupation numbers of
! ortogonalized atomic wfcs).
! These quantities are defined as follows: ns_{I,s,m1,m2} = \sum_{k,v}
! f_{kv} <\fi^{at}_{I,m1}|\psi_{k,v,s}><\psi_{k,v,s}|\fi^{at}_{I,m2}>
!
USE io_global, ONLY : stdout
USE kinds, ONLY : DP
USE ions_base, ONLY : nat, ityp
USE basis, ONLY : natomwfc
USE klist, ONLY : nks, ngk
USE ldaU, ONLY : Hubbard_lmax, Hubbard_l, oatwfc, &
Hubbard_U, Hubbard_alpha, swfcatom
USE symme, ONLY : d1, d2, d3
USE lsda_mod, ONLY : lsda, current_spin, nspin, isk
USE symme, ONLY : nsym, irt
USE wvfct, ONLY : nbnd, npw, npwx, igk, wg
USE control_flags, ONLY : gamma_only
USE wavefunctions_module, ONLY : evc
USE gvect, ONLY : gstart
USE io_files, ONLY : iunigk, nwordwfc, iunwfc, nwordatwfc, iunsat
USE buffers, ONLY : get_buffer
USE mp_global, ONLY : intra_pool_comm, inter_pool_comm
USE mp, ONLY : mp_sum
IMPLICIT NONE
!
! I/O variables
!
REAL(DP) :: ns(2*Hubbard_lmax+1,2*Hubbard_lmax+1,nspin,nat)
INTEGER :: ik, ibnd, is, i, na, nb, nt, isym, m1, m2, &
m0, m00, ldim
! counter on k points
! " " bands
! " " spins
! in the natomwfc ordering
REAL(DP) , ALLOCATABLE :: nr (:,:,:,:)
REAL(DP) :: t0, scnds
! cpu time spent
REAL(DP), EXTERNAL :: ddot
COMPLEX(DP) :: zdotc
COMPLEX(DP) , ALLOCATABLE :: proj(:,:)
REAL(DP) :: psum
t0 = scnds ()
ldim = 2 * Hubbard_lmax + 1
ALLOCATE( proj(natomwfc,nbnd), nr(ldim,ldim,nspin,nat) )
!
! D_Sl for l=1, l=2 and l=3 are already initialized, for l=0 D_S0 is 1
!
! Offset of atomic wavefunctions initialized in setup and stored in oatwfc
!
nr (:,:,:,:) = 0.d0
ns (:,:,:,:) = 0.d0
!
! we start a loop on k points
!
IF (nks > 1) REWIND (iunigk)
DO ik = 1, nks
IF (lsda) current_spin = isk(ik)
npw = ngk (ik)
IF (nks > 1) THEN
READ (iunigk) igk
CALL get_buffer (evc, nwordwfc, iunwfc, ik)
END IF
CALL davcio (swfcatom, nwordatwfc, iunsat, ik, - 1)
!
! make the projection
!
DO ibnd = 1, nbnd
DO i = 1, natomwfc
IF ( gamma_only ) THEN
proj (i, ibnd) = 2.d0 * &
ddot(2*npw, swfcatom (1, i), 1, evc (1, ibnd), 1)
IF (gstart.EQ.2) proj (i, ibnd) = proj (i, ibnd) - &
swfcatom (1, i) * evc (1, ibnd)
ELSE
proj (i, ibnd) = zdotc (npw, swfcatom (1, i), 1, evc (1, ibnd), 1)
ENDIF
ENDDO
ENDDO
#ifdef __PARA
CALL mp_sum ( proj, intra_pool_comm )
#endif
!
! compute the occupation numbers (the quantities n(m1,m2)) of the
! atomic orbitals
!
DO na = 1, nat
nt = ityp (na)
IF (Hubbard_U(nt).NE.0.d0 .OR. Hubbard_alpha(nt).NE.0.d0) THEN
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = m1, 2 * Hubbard_l(nt) + 1
DO ibnd = 1, nbnd
nr(m1,m2,current_spin,na) = nr(m1,m2,current_spin,na) + &
wg(ibnd,ik) * DBLE( proj(oatwfc(na)+m2,ibnd) * &
CONJG(proj(oatwfc(na)+m1,ibnd)) )
ENDDO
ENDDO
ENDDO
ENDIF
ENDDO
! on k-points
ENDDO
#ifdef __PARA
CALL mp_sum( nr, inter_pool_comm )
#endif
IF (nspin.EQ.1) nr = 0.5d0 * nr
!
! impose hermiticity of n_{m1,m2}
!
DO na = 1, nat
nt = ityp(na)
DO is = 1, nspin
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = m1 + 1, 2 * Hubbard_l(nt) + 1
nr (m2, m1, is, na) = nr (m1, m2, is, na)
ENDDO
ENDDO
ENDDO
ENDDO
! symmetrize the quantities nr -> ns
DO na = 1, nat
nt = ityp (na)
IF (Hubbard_U(nt).NE.0.d0 .OR. Hubbard_alpha(nt).NE.0.d0) THEN
DO is = 1, nspin
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = 1, 2 * Hubbard_l(nt) + 1
DO isym = 1, nsym
nb = irt (isym, na)
DO m0 = 1, 2 * Hubbard_l(nt) + 1
DO m00 = 1, 2 * Hubbard_l(nt) + 1
IF (Hubbard_l(nt).EQ.0) THEN
ns(m1,m2,is,na) = ns(m1,m2,is,na) + &
nr(m0,m00,is,nb) / nsym
ELSE IF (Hubbard_l(nt).EQ.1) THEN
ns(m1,m2,is,na) = ns(m1,m2,is,na) + &
d1(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
d1(m00,m2,isym) / nsym
ELSE IF (Hubbard_l(nt).EQ.2) THEN
ns(m1,m2,is,na) = ns(m1,m2,is,na) + &
d2(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
d2(m00,m2,isym) / nsym
ELSE IF (Hubbard_l(nt).EQ.3) THEN
ns(m1,m2,is,na) = ns(m1,m2,is,na) + &
d3(m0 ,m1,isym) * nr(m0,m00,is,nb) * &
d3(m00,m2,isym) / nsym
ELSE
CALL errore ('new_ns', &
'angular momentum not implemented', &
ABS(Hubbard_l(nt)) )
END IF
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
ENDIF
ENDDO
! Now we make the matrix ns(m1,m2) strictly hermitean
DO na = 1, nat
nt = ityp (na)
IF (Hubbard_U(nt).NE.0.d0 .OR. Hubbard_alpha(nt).NE.0.d0) THEN
DO is = 1, nspin
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = m1, 2 * Hubbard_l(nt) + 1
psum = ABS ( ns(m1,m2,is,na) - ns(m2,m1,is,na) )
IF (psum.GT.1.d-10) THEN
WRITE( stdout, * ) na, is, m1, m2
WRITE( stdout, * ) ns (m1, m2, is, na)
WRITE( stdout, * ) ns (m2, m1, is, na)
CALL errore ('new_ns', 'non hermitean matrix', 1)
ELSE
ns(m1,m2,is,na) = 0.5d0 * (ns(m1,m2,is,na) + &
ns(m2,m1,is,na) )
ns(m2,m1,is,na) = ns(m1,m2,is,na)
ENDIF
ENDDO
ENDDO
ENDDO
ENDIF
ENDDO
DEALLOCATE ( proj, nr )
RETURN
END SUBROUTINE new_ns