mirror of https://gitlab.com/QEF/q-e.git
60 lines
1.6 KiB
Fortran
60 lines
1.6 KiB
Fortran
!
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! Copyright (C) 2001-2003 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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!-----------------------------------------------------------------------
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function sumkg (et, nbnd, nks, wk, degauss, ngauss, e, is, isk)
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!-----------------------------------------------------------------------
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!
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! This function computes the number of states under a given energy e
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!
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!
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USE kinds
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USE mp_global, ONLY : inter_pool_comm
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USE mp, ONLY : mp_sum
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implicit none
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! Output variable
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real(DP) :: sumkg
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! Input variables
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integer, intent(in) :: nks, nbnd, ngauss
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! input: the total number of K points
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! input: the number of bands
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! input: the type of smearing
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real(DP), intent(in) :: wk (nks), et (nbnd, nks), degauss, e
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! input: the weight of the k points
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! input: the energy eigenvalues
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! input: gaussian broadening
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! input: the energy to check
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integer, intent(in) :: is, isk(nks)
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!
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! local variables
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!
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real(DP), external :: wgauss
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! function which compute the smearing
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real(DP) ::sum1
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integer :: ik, ibnd
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! counter on k points
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! counter on the band energy
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!
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sumkg = 0.d0
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do ik = 1, nks
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sum1 = 0.d0
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if (is /= 0) then
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if (isk(ik).ne.is) cycle
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end if
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do ibnd = 1, nbnd
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sum1 = sum1 + wgauss ( (e-et (ibnd, ik) ) / degauss, ngauss)
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enddo
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sumkg = sumkg + wk (ik) * sum1
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enddo
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#ifdef __PARA
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call mp_sum ( sumkg, inter_pool_comm )
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#endif
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return
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end function sumkg
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