quantum-espresso/PHonon/PH/sym_dns.f90

198 lines
7.4 KiB
Fortran

!
! Copyright (C) 2001-2023 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 sym_dns (ldim, npe, dns)
!-----------------------------------------------------------------------
!! DFPT+U: This routine symmetrizes the first order variation of
!! the occupation matrices dns due to the perturbation caused
!! by the displacement of atoms.
!
!! Written by S. de Gironcoli and A. Floris.
!! Modified by I. Timrov (01.10.2018).
!
USE kinds, ONLY : DP
USE constants, ONLY : tpi
USE ions_base, ONLY : nat, ityp
USE ldaU, ONLY : Hubbard_l, is_hubbard
USE lsda_mod, ONLY : nspin
USE lr_symm_base, ONLY : nsymq, minus_q, irotmq, rtau, upert, upert_mq
USE qpoint, ONLY : xq
USE symm_base, ONLY : d1, d2, d3, irt
!
IMPLICIT NONE
!
INTEGER, INTENT(IN) :: ldim, npe
COMPLEX(DP), INTENT(INOUT) :: dns(ldim,ldim,nspin,nat,npe)
!
! ... local variables
!
INTEGER :: nt, ip, jp, na, nb, is, m1, m2, &
m0, m00, isym, irot
COMPLEX(DP), ALLOCATABLE :: dnr(:,:,:,:,:), dnraux(:,:,:,:,:)
COMPLEX(DP) :: phase
REAL(DP) :: arg
!
IF ((nsymq==1) .AND. (.NOT.minus_q)) RETURN
!
! Initialization
!
! D_Sl for l=1, l=2 and l=3 are already initialized, for l=0 D_S0 is 1
!
ALLOCATE (dnraux(ldim,ldim,nspin,nat,npe))
ALLOCATE (dnr(ldim,ldim,nspin,nat,npe))
!
dnraux = (0.d0, 0.d0)
dnr = (0.d0, 0.d0)
!
! Impose hermiticity of dns_{m1,m2, is,na,ip} for m1<->m2
! and put it in dnr zeroing dns
!
DO ip = 1, npe
DO na = 1, nat
nt = ityp(na)
DO is = 1, nspin
DO m1 = 1, 2*Hubbard_l(nt)+1
DO m2 = 1, 2*Hubbard_l(nt)+1
dnr(m1, m2, is, na,ip) = 0.5d0 * ( dns(m1, m2, is, na, ip) &
+ dns(m2, m1, is, na, ip) )
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
!
dns = (0.d0, 0.d0)
!
! Symmetrize with -q if present (output overwritten on dnr)
!
IF (minus_q) THEN
DO ip = 1, npe
DO na = 1, nat
nt = ityp(na)
IF (is_hubbard(nt)) THEN
!
arg = ( xq(1) * rtau(1,irotmq,na) + &
xq(2) * rtau(2,irotmq,na) + &
xq(3) * rtau(3,irotmq,na) ) * tpi
phase = CMPLX (COS(arg), SIN(arg), kind=DP)
!
DO is = 1, nspin
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = 1, 2 * Hubbard_l(nt) + 1
nb = irt(irotmq, na)
DO m0 = 1, 2 * Hubbard_l(nt) + 1
DO m00 = 1, 2 * Hubbard_l(nt) + 1
DO jp = 1, npe
IF (Hubbard_l(nt).EQ.0) THEN
dns(m1,m2,is,na,ip) = dns(m1,m2,is,na,ip) + &
dnr(m0,m00,is,nb,jp) * upert_mq(jp,ip) * &
phase
ELSE IF (Hubbard_l(nt).EQ.1) THEN
dns(m1,m2,is,na,ip) = dns(m1,m2,is,na,ip) + &
d1(m0 ,m1,irotmq) * d1(m00,m2,irotmq) * &
dnr(m0,m00,is,nb,jp) * upert_mq(jp,ip) * &
phase
ELSE IF (Hubbard_l(nt).EQ.2) THEN
dns(m1,m2,is,na,ip) = dns(m1,m2,is,na,ip) + &
d2(m0 ,m1,irotmq) * d2(m00,m2,irotmq) * &
dnr(m0,m00,is,nb,jp) * upert_mq(jp,ip) * &
phase
ELSE IF (Hubbard_l(nt).EQ.3) THEN
dns(m1,m2,is,na,ip) = dns(m1,m2,is,na,ip) + &
d3(m0 ,m1,irotmq) * d3(m00,m2,irotmq) * &
dnr(m0,m00,is,nb,jp) * upert_mq(jp,ip) * &
phase
ELSE
CALL errore ('sym_dns', &
'angular momentum not implemented', &
ABS(Hubbard_l(nt)) )
ENDIF
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
ENDIF
ENDDO
ENDDO
dnr(:,:,:,:,:) = 0.5d0 * ( dnr(:,:,:,:,:) + CONJG(dns(:,:,:,:,:)) )
dns = (0.d0, 0.d0)
ENDIF
!
dnraux = (0.d0, 0.d0)
!
! Symmetryze dnr -> dns
!
DO isym = 1, nsymq
!
dns = (0.d0, 0.d0)
!
irot = isym
!
DO ip = 1, npe
DO na = 1, nat
nt = ityp(na)
IF (is_hubbard(nt)) THEN
!
arg = ( xq(1) * rtau(1,irot,na) + &
xq(2) * rtau(2,irot,na) + &
xq(3) * rtau(3,irot,na) ) * tpi
phase = CMPLX (COS(arg), SIN(arg), kind=DP )
!
DO m1 = 1, 2 * Hubbard_l(nt) + 1
DO m2 = 1, 2 * Hubbard_l(nt) + 1
nb = irt (irot, na)
DO m0 = 1, 2 * Hubbard_l(nt) + 1
DO m00 = 1, 2 * Hubbard_l(nt) + 1
do jp=1, npe
IF (Hubbard_l(nt).EQ.0) THEN
dns(m1,m2,:,na,ip) = dns(m1,m2,:,na,ip) + &
dnr(m0,m00,:,nb,jp) * upert(jp,ip,irot) * &
phase
ELSE IF (Hubbard_l(nt).EQ.1) THEN
dns(m1,m2,:,na,ip) = dns(m1,m2,:,na,ip) + &
d1(m0 ,m1,irot) * d1(m00,m2,irot) * &
dnr(m0,m00,:,nb,jp) * upert(jp,ip,irot) * &
phase
ELSE IF (Hubbard_l(nt).EQ.2) THEN
dns(m1,m2,:,na,ip) = dns(m1,m2,:,na,ip) + &
d2(m0 ,m1,irot) * d2(m00,m2,irot) * &
dnr(m0,m00,:,nb,jp) * upert(jp,ip,irot) * &
phase
ELSE IF (Hubbard_l(nt).EQ.3) THEN
dns(m1,m2,:,na,ip) = dns(m1,m2,:,na,ip) + &
d3(m0 ,m1,irot) * d3(m00,m2,irot) * &
dnr(m0,m00,:,nb,jp) * upert(jp,ip,irot) * &
phase
ELSE
CALL errore ('new_ns', &
'angular momentum not implemented', &
ABS(Hubbard_l(nt)) )
ENDIF
ENDDO
ENDDO
ENDDO
ENDDO
ENDDO
ENDIF
ENDDO
ENDDO
dnraux = dnraux + dns / nsymq
ENDDO
dns = dnraux
!
DEALLOCATE (dnr)
DEALLOCATE (dnraux)
!
RETURN
!
END SUBROUTINE sym_dns
!---------------------------------------------------------------------