mirror of https://gitlab.com/QEF/q-e.git
63 lines
1.6 KiB
Fortran
63 lines
1.6 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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subroutine delta_e (nr1, nr2, nr3, nrxx, rho, v_in, v_out, omega, &
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de, deband, nspin)
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USE kinds
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implicit none
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integer :: nspin, nr1, nr2, nr3, nrxx, i, ipol
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! nspin=1 if LDA, nspin=2 if LSDA
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! fft grid dimensions
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! counters
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real(kind=DP) :: rho (nrxx, nspin), v_in (nrxx, nspin), v_out (nrxx, &
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nspin), omega, de, deband
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! charge density
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! in and ...
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! ... out potentials from potential mixing
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! cell volume
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! total energy and band energy corrections
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de = 0.d0
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deband = 0.d0
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if (nspin.ne.2) then
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!
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! LDA case
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!
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do ipol=1,nspin
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do i = 1, nrxx
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de = de + rho(i,ipol) * ( v_out(i,ipol) - v_in(i,ipol) )
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deband = deband - rho(i,ipol) * v_in(i,ipol)
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enddo
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enddo
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else
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!
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! LSDA case
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!
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do i = 1, nrxx
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de = de + rho(i,1) * ( v_out(i,1) - v_in(i,1) ) + &
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rho(i,2) * ( v_out(i,2) - v_in(i,2) )
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deband = deband - rho(i,1) * v_in(i,1) - rho(i,2) * v_in(i,2)
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enddo
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endif
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de = omega * de / (nr1 * nr2 * nr3)
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deband = omega * deband / (nr1 * nr2 * nr3)
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#ifdef __PARA
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call reduce (1, de)
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call reduce (1, deband)
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#endif
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return
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end subroutine delta_e
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