quantum-espresso/PW/sum_band.f90

696 lines
23 KiB
Fortran

!
! Copyright (C) 2001-2005 PWSCF 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 .
!
#include "f_defs.h"
!
!----------------------------------------------------------------------------
SUBROUTINE sum_band()
!----------------------------------------------------------------------------
!
! ... calculates the symmetrized charge density and sum of occupied
! ... eigenvalues.
! ... this version works also for metals (gaussian spreading technique)
!
USE kinds, ONLY : DP
USE ener, ONLY : eband
USE wvfct, ONLY : gamma_only
USE control_flags, ONLY : diago_full_acc
USE cell_base, ONLY : at, bg, omega, tpiba
USE ions_base, ONLY : nat, ntyp => nsp, ityp
USE gvect, ONLY : nr1, nr2, nr3, nrx1, nrx2, nrx3, nrxx, ngm, g
USE gsmooth, ONLY : nls, nlsm, nr1s, nr2s, nr3s, &
nrx1s, nrx2s, nrx3s, nrxxs, doublegrid
USE klist, ONLY : nks, nkstot, wk, xk, ngk
USE ldaU, ONLY : lda_plus_U
USE lsda_mod, ONLY : lsda, nspin, current_spin, isk
USE scf, ONLY : rho, tauk
USE symme, ONLY : nsym, s, ftau
USE io_files, ONLY : iunwfc, nwordwfc, iunigk
USE buffers, ONLY : get_buffer
USE uspp, ONLY : nkb, vkb, becsum, nhtol, nhtoj, indv, okvan
USE uspp_param, ONLY : nh, tvanp, nhm
USE wavefunctions_module, ONLY : evc, psic, psic_nc
USE noncollin_module, ONLY : noncolin, npol
USE spin_orb, ONLY : lspinorb, domag, so, fcoef
USE wvfct, ONLY : nbnd, npwx, npw, igk, wg, et, btype
USE mp_global, ONLY : intra_image_comm, me_image, &
root_image, npool, my_pool_id
USE mp, ONLY : mp_bcast
USE funct, ONLY : dft_is_meta
!
IMPLICIT NONE
!
! ... local variables
!
INTEGER :: ikb, jkb, ijkb0, ih, jh, ijh, na, np
! counters on beta functions, atoms, pseudopotentials
INTEGER :: ir, is, ig, ibnd, ik, j
! counter on 3D r points
! counter on spin polarizations
! counter on g vectors
! counter on bands
! counter on k points
real (DP), allocatable :: kplusg (:)
!
!
CALL start_clock( 'sum_band' )
!
becsum(:,:,:) = 0.D0
rho(:,:) = 0.D0
eband = 0.D0
tauk(:,:) = 0.D0
if ( dft_is_meta() ) allocate (kplusg(npwx))
!
! ... calculates weights of Kohn-Sham orbitals used in calculation of rho
!
CALL weights ( )
!
IF ( diago_full_acc ) THEN
!
! ... for diagonalization purposes all the bands are considered occupied
!
btype(:,:) = 1
!
ELSE
!
! ... for diagonalization purposes a band is considered empty when its
! ... occupation is less than 1.0 %
!
btype(:,:) = 1
!
FORALL( ik = 1:nks, wk(ik) > 0.D0 )
!
WHERE( wg(:,ik) / wk(ik) < 0.01D0 ) btype(:,ik) = 0
!
END FORALL
!
END IF
!
! ... Needed for LDA+U
!
IF ( lda_plus_u ) CALL new_ns()
!
! ... specific routines are called to sum for each k point the contribution
! ... of the wavefunctions to the charge
!
IF ( gamma_only ) THEN
!
CALL sum_band_gamma()
!
ELSE
!
CALL sum_band_k()
!
END IF
!
! ... If a double grid is used, interpolate onto the fine grid
!
IF ( doublegrid ) THEN
!
DO is = 1, nspin
!
CALL interpolate( rho(1,is), rho(1,is), 1 )
if (dft_is_meta() ) CALL interpolate( tauk(1,is), tauk(1,is), 1 )
!
END DO
!
END IF
!
! ... Here we add the Ultrasoft contribution to the charge
!
IF ( okvan ) CALL addusdens()
!
IF ( noncolin .AND. .NOT. domag ) rho(:,2:4)=0.D0
!
CALL poolreduce( 1, eband )
!
! ... symmetrization of the charge density (and local magnetization)
!
#if defined (__PARA)
!
! ... reduce charge density across pools
!
CALL poolreduce( nspin * nrxx, rho )
if (dft_is_meta() ) CALL poolreduce( nspin * nrxx, tauk )
!
IF ( noncolin ) THEN
!
CALL psymrho( rho(1,1), nrx1, nrx2, nrx3, nr1, nr2, nr3, nsym, s, ftau )
!
IF ( domag ) &
CALL psymrho_mag( rho(1,2), nrx1, nrx2, nrx3, &
nr1, nr2, nr3, nsym, s, ftau, bg, at )
!
ELSE
!
DO is = 1, nspin
!
CALL psymrho( rho(1,is), nrx1, nrx2, nrx3, &
nr1, nr2, nr3, nsym, s, ftau )
if (dft_is_meta() ) CALL psymrho( tauk(1,is), nrx1, nrx2, nrx3, &
nr1, nr2, nr3, nsym, s, ftau )
!
END DO
!
END IF
!
#else
!
IF ( noncolin ) THEN
!
CALL symrho( rho(1,1), nrx1, nrx2, nrx3, nr1, nr2, nr3, nsym, s, ftau )
!
IF ( domag ) &
CALL symrho_mag( rho(1,2), nrx1, nrx2, nrx3, &
nr1, nr2, nr3, nsym, s, ftau, bg, at )
!
ELSE
!
DO is = 1, nspin
!
CALL symrho( rho(1,is), nrx1, nrx2, nrx3, nr1, nr2, nr3, nsym, s, ftau )
if (dft_is_meta() ) CALL symrho( tauk(1,is), nrx1, nrx2, nrx3, &
nr1, nr2, nr3, nsym, s, ftau )
!
END DO
!
END IF
!
#endif
if (dft_is_meta() ) deallocate (kplusg)
!
CALL stop_clock( 'sum_band' )
!
RETURN
!
CONTAINS
!
! ... internal procedures
!
!-----------------------------------------------------------------------
SUBROUTINE sum_band_gamma()
!-----------------------------------------------------------------------
!
! ... gamma version
!
IMPLICIT NONE
!
! ... local variables
!
REAL(DP) :: w1, w2
! weights
REAL(DP), ALLOCATABLE :: becp(:,:)
! contains <beta|psi>
!
!
ALLOCATE( becp( nkb, nbnd ) )
!
! ... here we sum for each k point the contribution
! ... of the wavefunctions to the charge
!
IF ( nks > 1 ) REWIND( iunigk )
!
k_loop: 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
!
IF ( nkb > 0 ) &
CALL init_us_2( npw, igk, xk(1,ik), vkb )
!
! ... here we compute the band energy: the sum of the eigenvalues
!
DO ibnd = 1, nbnd
!
! ... the sum of eband and demet is the integral for
! ... e < ef of e n(e) which reduces for degauss=0 to the sum of
! ... the eigenvalues.
!
eband = eband + et(ibnd,ik) * wg(ibnd,ik)
!
END DO
!
DO ibnd = 1, nbnd, 2
!
psic(:) = ( 0.D0, 0.D0 )
!
IF ( ibnd < nbnd ) THEN
!
! ... two ffts at the same time
!
psic(nls(igk(1:npw))) = evc(1:npw,ibnd) + &
( 0.D0, 1.D0 ) * evc(1:npw,ibnd+1)
psic(nlsm(igk(1:npw))) = CONJG( evc(1:npw,ibnd) - &
( 0.D0, 1.D0 ) * evc(1:npw,ibnd+1) )
!
ELSE
!
psic(nls(igk(1:npw))) = evc(1:npw,ibnd)
psic(nlsm(igk(1:npw))) = CONJG( evc(1:npw,ibnd) )
!
END IF
!
CALL cft3s( psic, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, 2 )
!
w1 = wg(ibnd,ik) / omega
!
! ... increment the charge density ...
!
IF ( ibnd < nbnd ) THEN
!
! ... two ffts at the same time
!
w2 = wg(ibnd+1,ik) / omega
!
ELSE
!
w2 = w1
!
END IF
!
DO ir = 1, nrxxs
!
rho(ir,current_spin) = rho(ir,current_spin) + &
w1 * DBLE( psic(ir) )**2 + &
w2 * AIMAG( psic(ir) )**2
!
END DO
!
IF (dft_is_meta()) THEN
DO j=1,3
psic(:) = ( 0.D0, 0.D0 )
!
kplusg (1:npw) = (xk(j,ik)+g(j,igk(1:npw))) * tpiba
IF ( ibnd < nbnd ) THEN
! ... two ffts at the same time
psic(nls(igk(1:npw))) = CMPLX (0d0, kplusg(1:npw)) * &
( evc(1:npw,ibnd) + &
( 0.D0, 1.D0 ) * evc(1:npw,ibnd+1) )
psic(nlsm(igk(1:npw))) = CMPLX (0d0, -kplusg(1:npw)) * &
CONJG( evc(1:npw,ibnd) - &
( 0.D0, 1.D0 ) * evc(1:npw,ibnd+1) )
ELSE
psic(nls(igk(1:npw))) = CMPLX (0d0, kplusg(1:npw)) * &
evc(1:npw,ibnd)
psic(nlsm(igk(1:npw))) = CMPLX (0d0, -kplusg(1:npw)) * &
CONJG( evc(1:npw,ibnd) )
END IF
!
CALL cft3s( psic, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, 2 )
!
! ... increment the kinetic energy density ...
!
DO ir = 1, nrxxs
tauk(ir,current_spin) = tauk(ir,current_spin) + &
w1 * DBLE( psic(ir) )**2 + &
w2 * AIMAG( psic(ir) )**2
END DO
!
END DO
END IF
!
!
END DO
!
! ... If we have a US pseudopotential we compute here the becsum term
!
IF ( .NOT. okvan ) CYCLE k_loop
!
IF ( nkb > 0 ) &
CALL ccalbec( nkb, npwx, npw, nbnd, becp, vkb, evc )
!
CALL start_clock( 'becsum' )
!
DO ibnd = 1, nbnd
!
w1 = wg(ibnd,ik)
ijkb0 = 0
!
DO np = 1, ntyp
!
IF ( tvanp(np) ) THEN
!
DO na = 1, nat
!
IF ( ityp(na) == np ) THEN
!
ijh = 1
!
DO ih = 1, nh(np)
!
ikb = ijkb0 + ih
!
becsum(ijh,na,current_spin) = &
becsum(ijh,na,current_spin) + &
w1 * becp(ikb,ibnd) * becp(ikb,ibnd)
!
ijh = ijh + 1
!
DO jh = ( ih + 1 ), nh(np)
!
jkb = ijkb0 + jh
!
becsum(ijh,na,current_spin) = &
becsum(ijh,na,current_spin) + &
w1 * 2.D0 * becp(ikb,ibnd) * becp(jkb,ibnd)
!
ijh = ijh + 1
!
END DO
!
END DO
!
ijkb0 = ijkb0 + nh(np)
!
END IF
!
END DO
!
ELSE
!
DO na = 1, nat
!
IF ( ityp(na) == np ) ijkb0 = ijkb0 + nh(np)
!
END DO
!
END IF
!
END DO
!
END DO
!
CALL stop_clock( 'becsum' )
!
END DO k_loop
!
DEALLOCATE( becp )
!
RETURN
!
END SUBROUTINE sum_band_gamma
!
!
!-----------------------------------------------------------------------
SUBROUTINE sum_band_k()
!-----------------------------------------------------------------------
!
! ... k-points version
!
IMPLICIT NONE
!
! ... local variables
!
REAL(DP) :: w1
! weights
COMPLEX(DP), ALLOCATABLE :: becp(:,:), becp_nc(:,:,:)
! contains <beta|psi>
!
COMPLEX(DP), ALLOCATABLE :: becsum_nc(:,:,:,:)
!
INTEGER :: ipol, kh, kkb, is1, is2, js
!
IF (okvan) THEN
IF (noncolin) THEN
ALLOCATE(becsum_nc(nhm*(nhm+1)/2,nat,npol,npol))
becsum_nc=(0.d0, 0.d0)
ALLOCATE( becp_nc( nkb, npol, nbnd ) )
ELSE
ALLOCATE( becp( nkb, nbnd ) )
END IF
ENDIF
!
! ... here we sum for each k point the contribution
! ... of the wavefunctions to the charge
!
IF ( nks > 1 ) REWIND( iunigk )
!
k_loop: 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
!
IF ( nkb > 0 ) &
CALL init_us_2( npw, igk, xk(1,ik), vkb )
!
! ... here we compute the band energy: the sum of the eigenvalues
!
DO ibnd = 1, nbnd
!
eband = eband + et(ibnd,ik) * wg(ibnd,ik)
!
! ... the sum of eband and demet is the integral for e < ef of
! ... e n(e) which reduces for degauss=0 to the sum of the
! ... eigenvalues
w1 = wg(ibnd,ik) / omega
IF (noncolin) THEN
psic_nc = (0.D0,0.D0)
DO ig = 1, npw
psic_nc(nls(igk(ig)),1)=evc(ig ,ibnd)
psic_nc(nls(igk(ig)),2)=evc(ig+npwx,ibnd)
END DO
call cft3s (psic_nc(1,1), nr1s, nr2s, nr3s, &
nrx1s,nrx2s,nrx3s, 2)
call cft3s (psic_nc(1,2), nr1s, nr2s, nr3s, &
nrx1s,nrx2s,nrx3s, 2)
!
! increment the charge density ...
!
DO ipol=1,npol
DO ir = 1, nrxxs
rho (ir, 1) = rho (ir, 1) + &
w1*( DBLE(psic_nc(ir,ipol))**2+AIMAG(psic_nc(ir,ipol))**2)
END DO
END DO
!
! In this case, calculate also the three
! components of the magnetization (stored in rho(ir,2-4) )
!
IF (domag) THEN
DO ir = 1,nrxxs
rho(ir,2) = rho(ir,2) + w1*2.D0* &
(DBLE(psic_nc(ir,1))* DBLE(psic_nc(ir,2)) + &
AIMAG(psic_nc(ir,1))*AIMAG(psic_nc(ir,2)))
rho(ir,3) = rho(ir,3) + w1*2.D0* &
(DBLE(psic_nc(ir,1))*AIMAG(psic_nc(ir,2)) - &
DBLE(psic_nc(ir,2))*AIMAG(psic_nc(ir,1)))
rho(ir,4) = rho(ir,4) + w1* &
(DBLE(psic_nc(ir,1))**2+AIMAG(psic_nc(ir,1))**2 &
-DBLE(psic_nc(ir,2))**2-AIMAG(psic_nc(ir,2))**2)
END DO
ELSE
rho(:,2:4)=0.d0
END IF
!
ELSE
!
psic(:) = ( 0.D0, 0.D0 )
!
psic(nls(igk(1:npw))) = evc(1:npw,ibnd)
!
CALL cft3s( psic, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, 2 )
!
! ... increment the charge density ...
!
DO ir = 1, nrxxs
!
rho(ir,current_spin) = rho(ir,current_spin) + &
w1 * ( DBLE( psic(ir) )**2 + &
AIMAG( psic(ir) )**2 )
!
END DO
!
IF (dft_is_meta()) THEN
DO j=1,3
psic(:) = ( 0.D0, 0.D0 )
!
kplusg (1:npw) = (xk(j,ik)+g(j,igk(1:npw))) * tpiba
psic(nls(igk(1:npw))) = CMPLX (0d0, kplusg(1:npw)) * &
evc(1:npw,ibnd)
!
CALL cft3s( psic, nr1s, nr2s, nr3s, nrx1s, nrx2s, nrx3s, 2 )
!
! ... increment the kinetic energy density ...
!
DO ir = 1, nrxxs
tauk(ir,current_spin) = tauk(ir,current_spin) + &
w1 * ( DBLE( psic(ir) )**2 + &
AIMAG( psic(ir) )**2 )
END DO
!
END DO
END IF
!
END IF
!
END DO
!
! ... If we have a US pseudopotential we compute here the becsum term
!
IF ( .NOT. okvan ) CYCLE k_loop
!
IF (noncolin) THEN
IF ( nkb > 0 ) &
CALL ccalbec_nc( nkb, npwx, npw, npol, nbnd, &
becp_nc, vkb, evc )
ELSE
IF ( nkb > 0 ) &
CALL ccalbec( nkb, npwx, npw, nbnd, becp, vkb, evc )
ENDIF
!
CALL start_clock( 'becsum' )
!
DO ibnd = 1, nbnd
!
w1 = wg(ibnd,ik)
ijkb0 = 0
!
DO np = 1, ntyp
!
IF ( tvanp(np) ) THEN
!
DO na = 1, nat
!
IF (ityp(na)==np) THEN
!
ijh = 1
!
DO ih = 1, nh(np)
!
ikb = ijkb0 + ih
!
IF (noncolin) THEN
!
DO is=1,npol
!
DO js=1,npol
becsum_nc(ijh,na,is,js) = &
becsum_nc(ijh,na,is,js)+w1 * &
CONJG(becp_nc(ikb,is,ibnd)) * &
becp_nc(ikb,js,ibnd)
END DO
!
END DO
!
ELSE
!
becsum(ijh,na,current_spin) = &
becsum(ijh,na,current_spin) + &
w1 * DBLE( CONJG( becp(ikb,ibnd) ) * &
becp(ikb,ibnd) )
!
END IF
!
ijh = ijh + 1
!
DO jh = ( ih + 1 ), nh(np)
!
jkb = ijkb0 + jh
!
IF (noncolin) THEN
!
DO is=1,npol
!
DO js=1,npol
becsum_nc(ijh,na,is,js) = &
becsum_nc(ijh,na,is,js) + w1 * &
CONJG(becp_nc(ikb,is,ibnd)) * &
becp_nc(jkb,js,ibnd)
END DO
!
END DO
!
ELSE
!
becsum(ijh,na,current_spin) = &
becsum(ijh,na,current_spin) + w1 * 2.D0 * &
DBLE( CONJG( becp(ikb,ibnd) ) * &
becp(jkb,ibnd) )
ENDIF
!
ijh = ijh + 1
!
END DO
!
END DO
!
ijkb0 = ijkb0 + nh(np)
!
END IF
!
END DO
!
ELSE
!
DO na = 1, nat
!
IF ( ityp(na) == np ) ijkb0 = ijkb0 + nh(np)
!
END DO
!
END IF
!
END DO
!
END DO
!
CALL stop_clock( 'becsum' )
!
END DO k_loop
IF (noncolin.and.okvan) THEN
DO np = 1, ntyp
IF ( tvanp(np) ) THEN
DO na = 1, nat
IF (ityp(na)==np) THEN
IF (so(np)) THEN
CALL transform_becsum_so(becsum_nc,becsum,na)
ELSE
CALL transform_becsum_nc(becsum_nc,becsum,na)
END IF
END IF
END DO
END IF
END DO
END IF
!
IF (okvan) THEN
IF (noncolin) THEN
DEALLOCATE( becsum_nc )
DEALLOCATE( becp_nc )
ELSE
DEALLOCATE( becp )
ENDIF
END IF
!
RETURN
!
END SUBROUTINE sum_band_k
!
END SUBROUTINE sum_band