mirror of
https://github.com/pfloos/quack
synced 2025-01-10 21:18:23 +01:00
77 lines
1.7 KiB
Fortran
77 lines
1.7 KiB
Fortran
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subroutine QP_graph_GF2(eta,nBas,nC,nO,nV,nR,nS,eHF,eGF2lin,ERI,eGF2)
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! Compute the graphical solution of the GF2 QP equation
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implicit none
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include 'parameters.h'
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! Input variables
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double precision,intent(in) :: eta
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integer,intent(in) :: nBas,nC,nO,nV,nR,nS
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double precision,intent(in) :: eHF(nBas)
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double precision,intent(in) :: eGF2lin(nBas)
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double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
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! Local variables
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integer :: p
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integer :: nIt
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integer,parameter :: maxIt = 64
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double precision,parameter :: thresh = 1d-6
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double precision,external :: SigmaC_GF2,dSigmaC_GF2
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double precision :: sigC,dsigC
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double precision :: f,df
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double precision :: w
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! Output variables
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double precision,intent(out) :: eGF2(nBas)
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! Run Newton's algorithm to find the root
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do p=nC+1,nBas-nR
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write(*,*) '-----------------'
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write(*,'(A10,I3)') 'Orbital ',p
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write(*,*) '-----------------'
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w = eGF2lin(p)
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nIt = 0
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f = 1d0
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write(*,'(A3,I3,A1,1X,3F15.9)') 'It.',nIt,':',w*HaToeV,f
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do while (abs(f) > thresh .and. nIt < maxIt)
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nIt = nIt + 1
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sigC = SigmaC_GF2(p,w,eta,nBas,nC,nO,nV,nR,nS,eHF,ERI)
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dsigC = dSigmaC_GF2(p,w,eta,nBas,nC,nO,nV,nR,nS,eHF,ERI)
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f = w - eHF(p) - sigC
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df = 1d0 - dsigC
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w = w - f/df
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write(*,'(A3,I3,A1,1X,3F15.9)') 'It.',nIt,':',w*HaToeV,f,sigC
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end do
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if(nIt == maxIt) then
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write(*,*) 'Newton root search has not converged!'
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else
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eGF2(p) = w
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write(*,'(A32,F16.10)') 'Quasiparticle energy (eV) ',eGF2(p)*HaToeV
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write(*,*)
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end if
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end do
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end subroutine QP_graph_GF2
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