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https://github.com/pfloos/quack
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43 lines
985 B
Fortran
43 lines
985 B
Fortran
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subroutine gga_correlation_energy(DFA,nEns,wEns,nGrid,weight,rho,drho,Ec)
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! Compute GGA correlation energy
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implicit none
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include 'parameters.h'
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! Input variables
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character(len=12),intent(in) :: DFA
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integer,intent(in) :: nEns
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double precision,intent(in) :: wEns(nEns)
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integer,intent(in) :: nGrid
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double precision,intent(in) :: weight(nGrid)
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double precision,intent(in) :: rho(nGrid,nspin)
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double precision,intent(in) :: drho(ncart,nGrid,nspin)
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! Local variables
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integer :: iG
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double precision :: ra,rb,ga,gb
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! Output variables
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double precision :: Ec(nsp)
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! Coefficients for ??? GGA exchange functional
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! Compute GGA exchange energy
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Ec(:) = 0d0
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do iG=1,nGrid
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ra = rho(iG,1)
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rb = rho(iG,2)
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ga = drho(1,iG,1)**2 + drho(2,iG,1)**2 + drho(3,iG,1)**2
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gb = drho(1,iG,2)**2 + drho(2,iG,2)**2 + drho(3,iG,2)**2
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enddo
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end subroutine gga_correlation_energy
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