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https://github.com/pfloos/quack
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37 lines
661 B
Fortran
37 lines
661 B
Fortran
subroutine CCSD_correlation_energy(nC,nO,nV,nR,OOVV,tau,EcCCSD)
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! Compute the CCSD energy
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implicit none
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! Input variables
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integer,intent(in) :: nC,nO,nV,nR
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double precision,intent(in) :: OOVV(nO,nO,nV,nV)
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double precision,intent(in) :: tau(nO,nO,nV,nV)
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! Local variables
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integer :: i,j,a,b
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! Output variables
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double precision,intent(out) :: EcCCSD
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EcCCSD = 0d0
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do i=nC+1,nO
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do j=nC+1,nO
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do a=1,nV-nR
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do b=1,nV-nR
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EcCCSD = EcCCSD + OOVV(i,j,a,b)*tau(i,j,a,b)
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enddo
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enddo
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enddo
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enddo
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EcCCSD = 0.5d0*EcCCSD
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end subroutine CCSD_correlation_energy
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