2020-03-26 16:57:46 +01:00
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subroutine CCD_correlation_energy(nC,nO,nV,nR,OOVV,t2,EcCCD)
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! Compute the CCD 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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2020-10-19 14:20:35 +02:00
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double precision,intent(in) :: OOVV(nO-nC,nO-nC,nV-nR,nV-nR)
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double precision,intent(in) :: t2(nO-nC,nO-nC,nV-nR,nV-nR)
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2020-03-26 16:57:46 +01:00
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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) :: EcCCD
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EcCCD = 0d0
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2020-10-19 14:20:35 +02:00
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do i=1,nO-nC
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do j=1,nO-nC
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2020-03-26 16:57:46 +01:00
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do a=1,nV-nR
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do b=1,nV-nR
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EcCCD = EcCCD + OOVV(i,j,a,b)*t2(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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EcCCD = 0.25d0*EcCCD
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end subroutine CCD_correlation_energy
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