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QuAcK/src/GW/QP_graph.f90

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subroutine QP_graph(nBas,nC,nO,nV,nR,nS,eta,eHF,SigX,Vxc,Omega,rho,eGWlin,eGW,regularize)
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! Compute the graphical solution of the QP equation
implicit none
include 'parameters.h'
! Input variables
integer,intent(in) :: nBas
integer,intent(in) :: nC
integer,intent(in) :: nO
integer,intent(in) :: nV
integer,intent(in) :: nR
integer,intent(in) :: nS
double precision,intent(in) :: eta
double precision,intent(in) :: eHF(nBas)
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double precision,intent(in) :: SigX(nBas)
double precision,intent(in) :: Vxc(nBas)
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double precision,intent(in) :: Omega(nS)
double precision,intent(in) :: rho(nBas,nBas,nS)
double precision,intent(in) :: eGWlin(nBas)
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logical,intent(in) :: regularize
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! Local variables
integer :: p
integer :: nIt
integer,parameter :: maxIt = 64
double precision,parameter :: thresh = 1d-6
double precision,external :: SigmaC,dSigmaC
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double precision :: sigC,dsigC
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double precision :: f,df
double precision :: w
! Output variables
double precision,intent(out) :: eGW(nBas)
! Run Newton's algorithm to find the root
do p=nC+1,nBas-nR
write(*,*) '-----------------'
write(*,'(A10,I3)') 'Orbital ',p
write(*,*) '-----------------'
w = eGWlin(p)
nIt = 0
f = 1d0
write(*,'(A3,I3,A1,1X,3F15.9)') 'It.',nIt,':',w*HaToeV,f
do while (abs(f) > thresh .and. nIt < maxIt)
nIt = nIt + 1
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sigC = SigmaC(p,w,eta,nBas,nC,nO,nV,nR,nS,eHF,Omega,rho,regularize)
dsigC = dSigmaC(p,w,eta,nBas,nC,nO,nV,nR,nS,eHF,Omega,rho,regularize)
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f = w - eHF(p) - SigX(p) - sigC + Vxc(p)
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
if(nIt == maxIt) then
write(*,*) 'Newton root search has not converged!'
else
eGW(p) = w
write(*,'(A32,F16.10)') 'Quasiparticle energy (eV) ',eGW(p)*HaToeV
write(*,*)
end if
end do
end subroutine QP_graph