mirror of https://gitlab.com/QEF/q-e.git
69 lines
1.6 KiB
Fortran
69 lines
1.6 KiB
Fortran
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!
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! Copyright (C) 2002 FPMD 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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! AB INITIO COSTANT PRESSURE MOLECULAR DYNAMICS
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! ----------------------------------------------
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! Car-Parrinello Parallel Program
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! Carlo Cavazzoni - Gerardo Ballabio
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! SISSA, Trieste, Italy - 1997-99
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! Last modified: Tue Nov 30 10:59:55 MET 1999
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! ----------------------------------------------
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! BEGIN manual
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SUBROUTINE enthropy(f,temp,nx,ent)
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! this routine computes the enthropic contribution due to the finite
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! temperature assigned to electrons when computing occupation numbers
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! ----------------------------------------------
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! END manual
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USE kinds
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IMPLICIT NONE
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! ... declare subroutine arguments
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INTEGER nx
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REAL(dbl) f(nx),temp,ent
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! ... declare other variables
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INTEGER i
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REAL(dbl) fm
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REAL(dbl), PARAMETER :: eps = 1.0e-10
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! end of declarations
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! ----------------------------------------------
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ent=0.d0
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DO i=1,nx
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fm=0.5d0*f(i)
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ent = ent+ fm*log(eps+fm)+(1.d0-fm)*log(eps+1.d0-fm)
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END DO
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ent=-2.d0*temp*ent
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RETURN
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END
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subroutine enthropy_s(f,temp,nx,ent)
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use kinds
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implicit none
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integer nx
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integer i
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real(dbl) f(nx),temp,ent, fm,eps
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parameter(eps=1.e-10)
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ent=0.d0
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do i=1,nx
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fm=0.5d0*f(i)
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ent = ent+ fm*log(eps+fm)+(1.d0-fm)*log(eps+1.d0-fm)
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enddo
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ent=-2.d0*temp*ent
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return
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end
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