quack/src/QuAcK/QuAcK.f90

program QuAcK

  implicit none
  include 'parameters.h'

  logical                       :: doSph
  logical                       :: unrestricted = .false.
  logical                       :: doRHF,doUHF,doMOM 
  logical                       :: dostab
  logical                       :: doKS
  logical                       :: doMP2,doMP3,doMP2F12
  logical                       :: doCCD,doDCD,doCCSD,doCCSDT
  logical                       :: do_drCCD,do_rCCD,do_lCCD,do_pCCD
  logical                       :: doCIS,doCIS_D,doCID,doCISD,doFCI
  logical                       :: doRPA,doRPAx,doppRPA
  logical                       :: doADC
  logical                       :: doG0F2,doevGF2,doqsGF2,doG0F3,doevGF3
  logical                       :: doG0W0,doevGW,doqsGW
  logical                       :: doG0T0,doevGT,doqsGT
  logical                       :: doMCMP2,doMinMCMP2
  logical                       :: doGTGW = .false.
  logical                       :: doBas

  integer                       :: nNuc,nBas,nBasCABS
  integer                       :: nEl(nspin)
  integer                       :: nC(nspin)
  integer                       :: nO(nspin)
  integer                       :: nV(nspin)
  integer                       :: nR(nspin)
  integer                       :: nS(nspin)
  double precision              :: ENuc,ERHF,EUHF,Norm
  double precision              :: EcMP2(3),EcMP3,EcMP2F12(3),EcMCMP2(3),Err_EcMCMP2(3),Var_EcMCMP2(3)

  double precision,allocatable  :: ZNuc(:),rNuc(:,:)
  double precision,allocatable  :: cHF(:,:,:),eHF(:,:),PHF(:,:,:)
  double precision,allocatable  :: Vxc(:,:)

  double precision,allocatable  :: eG0W0(:,:)
  double precision,allocatable  :: eG0T0(:,:)

  logical                       :: doACFDT
  logical                       :: exchange_kernel
  logical                       :: doXBS

  integer                       :: nShell
  integer,allocatable           :: TotAngMomShell(:)
  integer,allocatable           :: KShell(:)
  double precision,allocatable  :: CenterShell(:,:)
  double precision,allocatable  :: DShell(:,:)
  double precision,allocatable  :: ExpShell(:,:)
  integer,allocatable           :: max_ang_mom(:)
  double precision,allocatable  :: min_exponent(:,:)
  double precision,allocatable  :: max_exponent(:)

  integer                       :: TrialType
  double precision,allocatable  :: cTrial(:),gradient(:),hessian(:,:)

  double precision,allocatable  :: S(:,:)
  double precision,allocatable  :: T(:,:)
  double precision,allocatable  :: V(:,:)
  double precision,allocatable  :: Hc(:,:)
  double precision,allocatable  :: X(:,:)
  double precision,allocatable  :: dipole_int_AO(:,:,:)
  double precision,allocatable  :: dipole_int_MO(:,:,:)
  double precision,allocatable  :: dipole_int_aa(:,:,:)
  double precision,allocatable  :: dipole_int_bb(:,:,:)
  double precision,allocatable  :: ERI_AO(:,:,:,:)
  double precision,allocatable  :: ERI_MO(:,:,:,:)
  integer                       :: ixyz
  integer                       :: bra1,bra2
  integer                       :: ket1,ket2
  double precision,allocatable  :: ERI_MO_aaaa(:,:,:,:)
  double precision,allocatable  :: ERI_MO_aabb(:,:,:,:)
  double precision,allocatable  :: ERI_MO_bbbb(:,:,:,:)
  double precision,allocatable  :: ERI_ERF_AO(:,:,:,:)
  double precision,allocatable  :: ERI_ERF_MO(:,:,:,:)
  double precision,allocatable  :: F12(:,:,:,:),Yuk(:,:,:,:),FC(:,:,:,:,:,:)

  double precision              :: start_QuAcK  ,end_QuAcK    ,t_QuAcK
  double precision              :: start_int    ,end_int      ,t_int  
  double precision              :: start_HF     ,end_HF       ,t_HF
  double precision              :: start_stab   ,end_stab     ,t_stab
  double precision              :: start_KS     ,end_KS       ,t_KS
  double precision              :: start_MOM    ,end_MOM      ,t_MOM
  double precision              :: start_AOtoMO ,end_AOtoMO   ,t_AOtoMO
  double precision              :: start_CCD    ,end_CCD      ,t_CCD
  double precision              :: start_DCD    ,end_DCD      ,t_DCD
  double precision              :: start_CCSD   ,end_CCSD     ,t_CCSD
  double precision              :: start_CIS    ,end_CIS      ,t_CIS
  double precision              :: start_CID    ,end_CID      ,t_CID
  double precision              :: start_CISD   ,end_CISD     ,t_CISD
  double precision              :: start_FCI    ,end_FCI      ,t_FCI
  double precision              :: start_RPA    ,end_RPA      ,t_RPA 
  double precision              :: start_RPAx   ,end_RPAx     ,t_RPAx
  double precision              :: start_ppRPA  ,end_ppRPA    ,t_ppRPA
  double precision              :: start_ADC    ,end_ADC      ,t_ADC
  double precision              :: start_GF2    ,end_GF2      ,t_GF2
  double precision              :: start_GF3    ,end_GF3      ,t_GF3
  double precision              :: start_G0W0   ,end_G0W0     ,t_G0W0
  double precision              :: start_evGW   ,end_evGW     ,t_evGW
  double precision              :: start_qsGW   ,end_qsGW     ,t_qsGW
  double precision              :: start_G0T0   ,end_G0T0     ,t_G0T0
  double precision              :: start_evGT   ,end_evGT     ,t_evGT
  double precision              :: start_qsGT   ,end_qsGT     ,t_qsGT
  double precision              :: start_MP2    ,end_MP2      ,t_MP2
  double precision              :: start_MP3    ,end_MP3      ,t_MP3
  double precision              :: start_MP2F12 ,end_MP2F12   ,t_MP2F12
  double precision              :: start_MCMP2  ,end_MCMP2    ,t_MCMP2
  double precision              :: start_MinMCMP2,end_MinMCMP2,t_MinMCMP2
  double precision              :: start_Bas    ,end_Bas      ,t_Bas

  integer                       :: maxSCF_HF,n_diis_HF
  double precision              :: thresh_HF
  logical                       :: DIIS_HF,guess_type,ortho_type,mix

  integer                       :: maxSCF_CC,n_diis_CC
  double precision              :: thresh_CC
  logical                       :: DIIS_CC

  logical                       :: singlet
  logical                       :: triplet
  logical                       :: spin_conserved
  logical                       :: spin_flip
  logical                       :: TDA

  integer                       :: maxSCF_GF,n_diis_GF,renormGF
  double precision              :: thresh_GF
  logical                       :: DIIS_GF,linGF
  double precision              :: eta_GF

  integer                       :: maxSCF_GW,n_diis_GW
  double precision              :: thresh_GW
  logical                       :: DIIS_GW,COHSEX,SOSEX,TDA_W,G0W,GW0,linGW
  double precision              :: eta_GW

  logical                       :: BSE,dBSE,dTDA,evDyn

  integer                       :: nMC,nEq,nWalk,nPrint,iSeed
  double precision              :: dt
  logical                       :: doDrift

! Hello World

  write(*,*)
  write(*,*) '******************************************************************************************'
  write(*,*) '*            QuAcK                       QuAcK                         QuAcK             *'
  write(*,*) '*   __        __        __       __        __        __       __        __        __     *'
  write(*,*) '* <(o )___  <(o )___  <(o )___ <(o )___  <(o )___  <(o )___ <(o )___  <(o )___  <(o )___ *'
  write(*,*) '* ( ._> /   ( ._> /   ( ._> /  ( ._> /   ( ._> /   ( ._> /  ( ._> /   ( ._> /   ( ._> /  *'
  write(*,*) '*|--------------------------------------------------------------------------------------|*'
  write(*,*) '******************************************************************************************'
  write(*,*)

! Spherium calculation?
  
  doSph = .false.

  call cpu_time(start_QuAcK)

! Which calculations do you want to do?

  call read_methods(doRHF,doUHF,doKS,doMOM,           &
                    doMP2,doMP3,doMP2F12,             &
                    doCCD,doDCD,doCCSD,doCCSDT,       &
                    do_drCCD,do_rCCD,do_lCCD,do_pCCD, &
                    doCIS,doCIS_D,doCID,doCISD,doFCI, & 
                    doRPA,doRPAx,doppRPA,             &
                    doG0F2,doevGF2,doqsGF2,           & 
                    doG0F3,doevGF3,                   &
                    doG0W0,doevGW,doqsGW,             &
                    doG0T0,doevGT,doqsGT,             &
                    doMCMP2)

! Read options for methods

  call read_options(maxSCF_HF,thresh_HF,DIIS_HF,n_diis_HF,guess_type,ortho_type,mix,dostab, &
                    maxSCF_CC,thresh_CC,DIIS_CC,n_diis_CC,                                  &
                    TDA,singlet,triplet,spin_conserved,spin_flip,                           &
                    maxSCF_GF,thresh_GF,DIIS_GF,n_diis_GF,linGF,eta_GF,renormGF,            &
                    maxSCF_GW,thresh_GW,DIIS_GW,n_diis_GW,linGW,eta_GW,                     & 
                    COHSEX,SOSEX,TDA_W,G0W,GW0,                                             &  
                    doACFDT,exchange_kernel,doXBS,                                          &
                    BSE,dBSE,dTDA,evDyn,                                                    &
                    nMC,nEq,nWalk,dt,nPrint,iSeed,doDrift)

! Weird stuff

  doMinMCMP2 = .false.

!------------------------------------------------------------------------
! Read input information
!------------------------------------------------------------------------

! Read number of atoms, number of electrons of the system
! nC   = number of core orbitals
! nO   = number of occupied orbitals
! nV   = number of virtual orbitals (see below)
! nR   = number of Rydberg orbitals 
! nBas = number of basis functions (see below)
!      = nO + nV
! nS   = number of single excitation 
!      = nO*nV

  call read_molecule(nNuc,nEl(:),nO(:),nC(:),nR(:))
  allocate(ZNuc(nNuc),rNuc(nNuc,ncart))

! Read geometry

  call read_geometry(nNuc,ZNuc,rNuc,ENuc)

  allocate(CenterShell(maxShell,ncart),TotAngMomShell(maxShell),KShell(maxShell),DShell(maxShell,maxK), & 
           ExpShell(maxShell,maxK),max_ang_mom(nNuc),min_exponent(nNuc,maxL+1),max_exponent(nNuc))

!------------------------------------------------------------------------
! Read basis set information
!------------------------------------------------------------------------

  call read_basis(nNuc,rNuc,nBas,nO,nV,nShell,TotAngMomShell,CenterShell,KShell,DShell,ExpShell, & 
                  max_ang_mom,min_exponent,max_exponent)
  nS(:) = (nO(:) - nC(:))*(nV(:) - nR(:))

!------------------------------------------------------------------------
! Read auxiliary basis set information
!------------------------------------------------------------------------

! call ReadAuxBasis(nNuc,rNuc,nShell,CenterShell,TotAngMomShell,KShell,DShell,ExpShell)

! Compute the number of basis functions

! call CalcNBasis(nShell,TotAngMomShell,nA)

! Number of virtual orbitals in complete space

! nBasCABS = nA - nBas

!------------------------------------------------------------------------
! Read one- and two-electron integrals
!------------------------------------------------------------------------

! Memory allocation for one- and two-electron integrals

  allocate(cHF(nBas,nBas,nspin),eHF(nBas,nspin),eG0W0(nBas,nspin),eG0T0(nBas,nspin),PHF(nBas,nBas,nspin), &
           S(nBas,nBas),T(nBas,nBas),V(nBas,nBas),Hc(nBas,nBas),X(nBas,nBas),ERI_AO(nBas,nBas,nBas,nBas), &
           dipole_int_AO(nBas,nBas,ncart),dipole_int_MO(nBas,nBas,ncart),Vxc(nBas,nspin))

! Read integrals

  call cpu_time(start_int)

  if(doSph) then

    call read_integrals_sph(nBas,S,T,V,Hc,ERI_AO)  

  else

    call read_integrals(nBas,S,T,V,Hc,ERI_AO)
    call read_dipole_integrals(nBas,dipole_int_AO)

  end if

  call cpu_time(end_int)

    t_int = end_int - start_int
    write(*,*)
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for reading integrals = ',t_int,' seconds'
    write(*,*)

! Compute orthogonalization matrix

  call orthogonalization_matrix(ortho_type,nBas,S,X)

!------------------------------------------------------------------------
! Compute RHF energy
!------------------------------------------------------------------------

  if(doRHF) then

   ! Check that RHF calculation is worth doing...

   if(nO(1) /= nO(2)) then
     write(*,*) ' !!! The system does not appear to be closed shell !!!'
     write(*,*) 
     stop
   end if

    call cpu_time(start_HF)
    call RHF(maxSCF_HF,thresh_HF,n_diis_HF,guess_type,nNuc,ZNuc,rNuc,ENuc, &
             nBas,nO,S,T,V,Hc,ERI_AO,dipole_int_AO,X,ERHF,eHF,cHF,PHF,Vxc)
    call cpu_time(end_HF)

    t_HF = end_HF - start_HF
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for RHF = ',t_HF,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute UHF energy
!------------------------------------------------------------------------

  if(doUHF) then

    ! Switch on the unrestricted flag
    unrestricted = .true.

    call cpu_time(start_HF)
    call UHF(maxSCF_HF,thresh_HF,n_diis_HF,guess_type,mix,nNuc,ZNuc,rNuc,ENuc, & 
             nBas,nO,S,T,V,Hc,ERI_AO,dipole_int_AO,X,EUHF,eHF,cHF,PHF,Vxc)
    call cpu_time(end_HF)

    t_HF = end_HF - start_HF
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for UHF = ',t_HF,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute KS energy
!------------------------------------------------------------------------

  if(doKS) then

    ! Switch on the unrestricted flag
    unrestricted = .true.

    call cpu_time(start_KS)
    call eDFT(maxSCF_HF,thresh_HF,n_diis_HF,guess_type,mix,nNuc,ZNuc,rNuc,ENuc,nBas,nEl,nC, & 
              nO,nV,nR,nShell,TotAngMomShell,CenterShell,KShell,DShell,ExpShell,            &
              max_ang_mom,min_exponent,max_exponent,S,T,V,Hc,X,ERI_AO,dipole_int_AO,EUHF,eHF,cHF,PHF,Vxc)
             
    call cpu_time(end_KS)

    t_KS = end_KS - start_KS
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for KS = ',t_KS,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Maximum overlap method
!------------------------------------------------------------------------

  if(doMOM) then

    call cpu_time(start_MOM)

    if(unrestricted) then

!     call UMOM()

    else

      call RMOM(maxSCF_HF,thresh_HF,n_diis_HF,guess_type,nNuc,ZNuc,rNuc,ENuc, &
             nBas,nO,S,T,V,Hc,ERI_AO,dipole_int_AO,X,ERHF,eHF,cHF,PHF,Vxc)

    end if

    call cpu_time(end_MOM)

    t_MOM = end_MOM - start_MOM
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MOM = ',t_MOM,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! AO to MO integral transform for post-HF methods
!------------------------------------------------------------------------

  call cpu_time(start_AOtoMO)

  write(*,*)
  write(*,*) 'AO to MO transformation... Please be patient'
  write(*,*)

  if(doSph) then

    allocate(ERI_MO(nBas,nBas,nBas,nBas))
    ERI_MO(:,:,:,:) = ERI_AO(:,:,:,:)
    print*,'!!! MO = AO !!!'
    deallocate(ERI_AO)

  else

    if(unrestricted) then

      ! Read and transform dipole-related integrals
    
      allocate(dipole_int_aa(nBas,nBas,ncart),dipole_int_bb(nBas,nBas,ncart))
      dipole_int_aa(:,:,:) = dipole_int_AO(:,:,:)
      dipole_int_bb(:,:,:) = dipole_int_AO(:,:,:)
      do ixyz=1,ncart
          call AOtoMO_transform(nBas,cHF(:,:,1),dipole_int_aa(:,:,ixyz))
          call AOtoMO_transform(nBas,cHF(:,:,2),dipole_int_bb(:,:,ixyz))
      end do 

      ! Memory allocation
     
      allocate(ERI_MO_aaaa(nBas,nBas,nBas,nBas),ERI_MO_aabb(nBas,nBas,nBas,nBas),ERI_MO_bbbb(nBas,nBas,nBas,nBas))
     
      ! 4-index transform for (aa|aa) block
     
      bra1 = 1
      bra2 = 1
      ket1 = 1
      ket2 = 1
      call AOtoMO_integral_transform(bra1,bra2,ket1,ket2,nBas,cHF,ERI_AO,ERI_MO_aaaa)
      
      ! 4-index transform for (aa|bb) block
     
      bra1 = 1
      bra2 = 1
      ket1 = 2
      ket2 = 2
      call AOtoMO_integral_transform(bra1,bra2,ket1,ket2,nBas,cHF,ERI_AO,ERI_MO_aabb)
     
      ! 4-index transform for (bb|bb) block
     
      bra1 = 2
      bra2 = 2
      ket1 = 2
      ket2 = 2
      call AOtoMO_integral_transform(bra1,bra2,ket1,ket2,nBas,cHF,ERI_AO,ERI_MO_bbbb)

    else

      ! Memory allocation
     
      allocate(ERI_MO(nBas,nBas,nBas,nBas))
 
      ! Read and transform dipole-related integrals
    
      dipole_int_MO(:,:,:) = dipole_int_AO(:,:,:)
      do ixyz=1,ncart
        call AOtoMO_transform(nBas,cHF,dipole_int_MO(:,:,ixyz))
      end do 

      ! 4-index transform 
     
      bra1 = 1
      bra2 = 1
      ket1 = 1
      ket2 = 1
      call AOtoMO_integral_transform(bra1,bra2,ket1,ket2,nBas,cHF,ERI_AO,ERI_MO)

    end if

  end if

  call cpu_time(end_AOtoMO)

  t_AOtoMO = end_AOtoMO - start_AOtoMO
  write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for AO to MO transformation = ',t_AOtoMO,' seconds'
  write(*,*)

!------------------------------------------------------------------------
! Stability analysis of HF solution
!------------------------------------------------------------------------

  if(dostab) then

    call cpu_time(start_stab)

    if(unrestricted) then

      call UHF_stability(nBas,nC,nO,nV,nR,nS,eHF,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb)

    else

      call RHF_stability(nBas,nC,nO,nV,nR,nS,eHF,ERI_MO)

    end if

    call cpu_time(end_stab)

    t_stab = end_stab - start_stab
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for stability analysis = ',t_stab,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute MP2 energy
!------------------------------------------------------------------------

  if(doMP2) then

    call cpu_time(start_MP2)

    if(unrestricted) then

      call UMP2(nBas,nC,nO,nV,nR,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,ENuc,EUHF,eHF,EcMP2)

    else

      call MP2(nBas,nC,nO,nV,nR,ERI_MO,ENuc,ERHF,eHF,EcMP2)

    end if

    call cpu_time(end_MP2)

    t_MP2 = end_MP2 - start_MP2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MP2 = ',t_MP2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute MP3 energy
!------------------------------------------------------------------------

  if(doMP3) then

    call cpu_time(start_MP3)
    
    if(unrestricted) then

      write(*,*) 'MP3 NYI for UHF reference'
      stop

    else

      call MP3(nBas,nC,nO,nV,nR,ERI_MO,eHF,ENuc,ERHF)

    end if

    call cpu_time(end_MP3)

    t_MP3 = end_MP3 - start_MP3
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MP3 = ',t_MP3,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute MP2-F12 energy
!------------------------------------------------------------------------

  if(doMP2F12) then

    call cpu_time(start_MP2F12)

!   Memory allocation for one- and two-electron integrals

    allocate(F12(nBas,nBas,nBas,nBas),Yuk(nBas,nBas,nBas,nBas),FC(nBas,nBas,nBas,nBas,nBas,nBas))

!   Read integrals

    call read_F12_integrals(nBas,S,ERI_AO,F12,Yuk,FC)
    call MP2F12(nBas,nC,nO,nV,ERI_AO,F12,Yuk,FC,ERHF,eHF,cHF)
    call cpu_time(end_MP2F12)

    t_MP2F12 = end_MP2F12 - start_MP2F12
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MP2-F12 = ',t_MP2F12,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform CCD calculation
!------------------------------------------------------------------------

  if(doCCD) then

    call cpu_time(start_CCD)
    call CCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR, & 
             ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCD)

    t_CCD = end_CCD - start_CCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for CCD = ',t_CCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform DCD calculation
!------------------------------------------------------------------------

  if(doDCD) then

    call cpu_time(start_DCD)
    call DCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR, & 
             ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_DCD)

    t_DCD = end_DCD - start_DCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for DCD = ',t_DCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform CCSD or CCSD(T) calculation
!------------------------------------------------------------------------

  if(doCCSDT) doCCSD = .true.

  if(doCCSD) then

    call cpu_time(start_CCSD)
    call CCSD(maxSCF_CC,thresh_CC,n_diis_CC,doCCSDT,nBas,nC,nO,nV,nR, & 
              ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCSD)

    t_CCSD = end_CCSD - start_CCSD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for CCSD or CCSD(T)= ',t_CCSD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform direct ring CCD calculation
!------------------------------------------------------------------------

  if(do_drCCD) then

    call cpu_time(start_CCD)
    call drCCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR, &
               ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCD)

    t_CCD = end_CCD - start_CCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for direct ring CCD = ',t_CCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform ring CCD calculation
!------------------------------------------------------------------------

  if(do_rCCD) then

    call cpu_time(start_CCD)
    call rCCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR, &
              ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCD)

    t_CCD = end_CCD - start_CCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for ring CCD = ',t_CCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform ladder CCD calculation
!------------------------------------------------------------------------

  if(do_lCCD) then

    call cpu_time(start_CCD)
    call lCCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR, &
              ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCD)

    t_CCD = end_CCD - start_CCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for ladder CCD = ',t_CCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform pair CCD calculation
!------------------------------------------------------------------------

  if(do_pCCD) then

    call cpu_time(start_CCD)
    call pCCD(maxSCF_CC,thresh_CC,n_diis_CC,nBas,nC,nO,nV,nR,ERI_MO,ENuc,ERHF,eHF)
    call cpu_time(end_CCD)

    t_CCD = end_CCD - start_CCD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for pair CCD = ',t_CCD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute CIS excitations
!------------------------------------------------------------------------

  if(doCIS) then

    call cpu_time(start_CIS)
    if(unrestricted) then

      call UCIS(spin_conserved,spin_flip,nBas,nC,nO,nV,nR,nS,ERI_MO_aaaa,ERI_MO_aabb, & 
                ERI_MO_bbbb,dipole_int_aa,dipole_int_bb,eHF,cHF,S)

   else 

      call CIS(singlet,triplet,doCIS_D,nBas,nC,nO,nV,nR,nS,ERI_MO,dipole_int_MO,eHF)

    end if
    call cpu_time(end_CIS)

    t_CIS = end_CIS - start_CIS
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for CIS = ',t_CIS,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute CID excitations
!------------------------------------------------------------------------

  if(doCID) then

    call cpu_time(start_CID)
!   call CID(singlet,triplet,nBas,nC,nO,nV,nR,ERI_MO,eHF)
    call cpu_time(end_CID)

    t_CID = end_CID - start_CID
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for CID = ',t_CID,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute CISD excitations
!------------------------------------------------------------------------

  if(doCISD) then

    call cpu_time(start_CISD)
!   call CISD(singlet,triplet,nBas,nC,nO,nV,nR,ERI_MO,eHF)
    call cpu_time(end_CISD)

    t_CISD = end_CISD - start_CISD
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for CISD = ',t_CISD,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute (direct) RPA excitations
!------------------------------------------------------------------------

  if(doRPA) then

    call cpu_time(start_RPA)
    if(unrestricted) then

       call URPA(TDA,doACFDT,exchange_kernel,spin_conserved,spin_flip,0d0,nBas,nC,nO,nV,nR,nS,ENuc,EUHF, &
                  ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_aa,dipole_int_bb,eHF,cHF,S)

    else

      call RPA(TDA,doACFDT,exchange_kernel,singlet,triplet,0d0,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_MO,dipole_int_MO,eHF)

    end if
    call cpu_time(end_RPA)

    t_RPA = end_RPA - start_RPA
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for RPA = ',t_RPA,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute RPAx (RPA with exchange) excitations
!------------------------------------------------------------------------

  if(doRPAx) then

    call cpu_time(start_RPAx)
    if(unrestricted) then

       call URPAx(TDA,doACFDT,exchange_kernel,spin_conserved,spin_flip,0d0,nBas,nC,nO,nV,nR,nS,ENuc,EUHF, &
                  ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_aa,dipole_int_bb,eHF,cHF,S)

    else 

      call RPAx(TDA,doACFDT,exchange_kernel,singlet,triplet,0d0,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_MO,dipole_int_MO,eHF)

    end if
    call cpu_time(end_RPAx)

    t_RPAx = end_RPAx - start_RPAx
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for RPAx = ',t_RPAx,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute pp-RPA excitations
!------------------------------------------------------------------------

  if(doppRPA) then

    call cpu_time(start_ppRPA)
    call ppRPA(singlet,triplet,nBas,nC,nO,nV,nR,ENuc,ERHF,ERI_MO,eHF)
    call cpu_time(end_ppRPA)

    t_ppRPA = end_ppRPA - start_ppRPA
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for pp-RPA = ',t_ppRPA,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute ADC excitations
!------------------------------------------------------------------------

! if(doADC) then

!   call cpu_time(start_ADC)
!   call ADC(singlet,triplet,maxSCF_GF,thresh_GF,n_diis_GF, & 
!            nBas,nC,nO,nV,nR,eHF,ERI_MO)
!   call cpu_time(end_ADC)

!   t_ADC = end_ADC - start_ADC
!   write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for ADC = ',t_ADC,' seconds'
!   write(*,*)

! end if

!------------------------------------------------------------------------
! Compute G0F2 electronic binding energies
!------------------------------------------------------------------------

  if(doG0F2) then

    call cpu_time(start_GF2)

    if(unrestricted) then

      call UG0F2(BSE,TDA,dBSE,dTDA,evDyn,spin_conserved,spin_flip,linGF,eta_GF,nBas,nC,nO,nV,nR,nS,ENuc,EUHF, &
                 S,ERI_AO,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_aa,dipole_int_bb,eHF)

    else

      call G0F2(BSE,TDA,dBSE,dTDA,evDyn,singlet,triplet,linGF, & 
                eta_GF,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_MO,dipole_int_MO,eHF)

    end if

    call cpu_time(end_GF2)

    t_GF2 = end_GF2 - start_GF2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for GF2 = ',t_GF2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute evGF2 electronic binding energies
!------------------------------------------------------------------------

  if(doevGF2) then

    call cpu_time(start_GF2)

    if(unrestricted) then

      call evUGF2(maxSCF_GF,thresh_GF,n_diis_GF,BSE,TDA,dBSE,dTDA,evDyn,spin_conserved,spin_flip,    &
                  eta_GF,nBas,nC,nO,nV,nR,nS,ENuc,EUHF,S,ERI_AO,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb, & 
                  dipole_int_aa,dipole_int_bb,cHF,eHF)

    else

      call evGF2(BSE,TDA,dBSE,dTDA,evDyn,maxSCF_GF,thresh_GF,n_diis_GF, & 
                 singlet,triplet,linGF,eta_GF,nBas,nC,nO,nV,nR,nS,ENuc,ERHF, & 
                 ERI_MO,dipole_int_MO,eHF)

    end if

    call cpu_time(end_GF2)

    t_GF2 = end_GF2 - start_GF2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for GF2 = ',t_GF2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform qsGF2 calculation
!------------------------------------------------------------------------

  if(doqsGF2) then 

    call cpu_time(start_GF2)

    if(unrestricted) then

      call qsUGF2(maxSCF_GF,thresh_GF,n_diis_GF,BSE,TDA,dBSE,dTDA,evDyn,spin_conserved,spin_flip,eta_GF, &
                  nNuc,ZNuc,rNuc,ENuc,nBas,nC,nO,nV,nR,nS,EUHF,S,X,T,V,Hc,ERI_AO,                        & 
                  ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_AO,dipole_int_aa,dipole_int_bb,PHF,cHF,eHF)

    else

      call qsGF2(maxSCF_GF,thresh_GF,n_diis_GF,BSE,TDA,dBSE,dTDA,evDyn,singlet,triplet,eta_GF,nNuc,ZNuc,rNuc,ENuc, & 
                 nBas,nC,nO,nV,nR,nS,ERHF,S,X,T,V,Hc,ERI_AO,ERI_MO,dipole_int_AO,dipole_int_MO,PHF,cHF,eHF)

    end if

    call cpu_time(end_GF2)

    t_GF2 = end_GF2 - start_GF2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for qsGF2 = ',t_GF2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute G0F3 electronic binding energies
!------------------------------------------------------------------------

  if(doG0F3) then

    call cpu_time(start_GF3)
    call G0F3(renormGF,nBas,nC,nO,nV,nR,ERI_MO,eHF)
    call cpu_time(end_GF3)

    t_GF3 = end_GF3 - start_GF3
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for GF3 = ',t_GF3,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute evGF3 electronic binding energies
!------------------------------------------------------------------------

  if(doevGF3) then

    call cpu_time(start_GF3)
    call evGF3(maxSCF_GF,thresh_GF,n_diis_GF,renormGF,nBas,nC,nO,nV,nR,ERI_MO,eHF)
    call cpu_time(end_GF3)

    t_GF3 = end_GF3 - start_GF3
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for GF3 = ',t_GF3,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform G0W0 calculatiom
!------------------------------------------------------------------------

  eG0W0(:,:) = eHF(:,:)

  if(doG0W0) then
    
    call cpu_time(start_G0W0)
    if(unrestricted) then 

      call UG0W0(doACFDT,exchange_kernel,doXBS,COHSEX,BSE,TDA_W,TDA,dBSE,dTDA,evDyn,spin_conserved,spin_flip,   & 
                 linGW,eta_GW,nBas,nC,nO,nV,nR,nS,ENuc,EUHF,S,ERI_AO,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb, & 
                 dipole_int_aa,dipole_int_bb,PHF,cHF,eHF,Vxc,eG0W0)
    else

      call G0W0(doACFDT,exchange_kernel,doXBS,COHSEX,SOSEX,BSE,TDA_W,TDA,dBSE,dTDA,evDyn,singlet,triplet, &
                linGW,eta_GW,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_AO,ERI_MO,dipole_int_MO,PHF,cHF,eHF,Vxc,eG0W0)

    end if

    call cpu_time(end_G0W0)
  
    t_G0W0 = end_G0W0 - start_G0W0
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for G0W0 = ',t_G0W0,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform evGW calculation
!------------------------------------------------------------------------

  if(doevGW) then

    call cpu_time(start_evGW)
    if(unrestricted) then 

      call evUGW(maxSCF_GW,thresh_GW,n_diis_GW,doACFDT,exchange_kernel,doXBS,COHSEX,BSE,TDA_W,TDA,   &
                G0W,GW0,dBSE,dTDA,evDyn,spin_conserved,spin_flip,eta_GW,nBas,nC,nO,nV,nR,nS,ENuc,    &
                EUHF,S,ERI_AO,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_aa,dipole_int_bb, & 
                PHF,cHF,eHF,Vxc,eG0W0)

    else

      call evGW(maxSCF_GW,thresh_GW,n_diis_GW,doACFDT,exchange_kernel,doXBS,COHSEX,SOSEX,       &
                BSE,TDA_W,TDA,G0W,GW0,dBSE,dTDA,evDyn,singlet,triplet,eta_GW, &
                nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_AO,ERI_MO,dipole_int_MO,PHF,cHF,eHF,Vxc,eG0W0)
    end if
    call cpu_time(end_evGW)

    t_evGW = end_evGW - start_evGW
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for evGW = ',t_evGW,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform qsGW calculation
!------------------------------------------------------------------------

  if(doqsGW) then 

    call cpu_time(start_qsGW)

    if(unrestricted) then 
    
      call qsUGW(maxSCF_GW,thresh_GW,n_diis_GW,doACFDT,exchange_kernel,doXBS,COHSEX,SOSEX,BSE,TDA_W,TDA, &
                 G0W,GW0,dBSE,dTDA,evDyn,spin_conserved,spin_flip,eta_GW,nNuc,ZNuc,rNuc,ENuc,nBas,nC,nO, &
                 nV,nR,nS,EUHF,S,X,T,V,Hc,ERI_AO,ERI_MO_aaaa,ERI_MO_aabb,ERI_MO_bbbb,dipole_int_AO,      &
                 dipole_int_aa,dipole_int_bb,PHF,cHF,eHF)

    else
 
      call qsGW(maxSCF_GW,thresh_GW,n_diis_GW,doACFDT,exchange_kernel,doXBS,COHSEX,SOSEX,         &
                BSE,TDA_W,TDA,G0W,GW0,dBSE,dTDA,evDyn,singlet,triplet,eta_GW,nNuc,ZNuc,rNuc,ENuc, & 
                nBas,nC,nO,nV,nR,nS,ERHF,S,X,T,V,Hc,ERI_AO,ERI_MO,dipole_int_AO,dipole_int_MO,PHF,cHF,eHF)

    end if

    call cpu_time(end_qsGW)

    t_qsGW = end_qsGW - start_qsGW
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for qsGW = ',t_qsGW,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform G0T0 calculatiom
!------------------------------------------------------------------------

  eG0T0(:,:) = eHF(:,:)

  if(doG0T0) then
    
    call cpu_time(start_G0T0)
    call G0T0(doACFDT,exchange_kernel,doXBS,BSE,TDA_W,TDA,dBSE,dTDA,evDyn,singlet,triplet, &
              linGW,eta_GW,nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_AO,ERI_MO,dipole_int_MO,      &  
              PHF,cHF,eHF,Vxc,eG0T0)
    call cpu_time(end_G0T0)
  
    t_G0T0 = end_G0T0 - start_G0T0
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for G0T0 = ',t_G0T0,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Perform evGT calculatiom
!------------------------------------------------------------------------

  if(doevGT) then
    
    call cpu_time(start_evGT)
    call evGT(maxSCF_GW,thresh_GW,n_diis_GW,doACFDT,exchange_kernel,doXBS, &
              BSE,TDA_W,TDA,dBSE,dTDA,evDyn,singlet,triplet,eta_GW,        & 
              nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_AO,ERI_MO,dipole_int_MO,   &
              PHF,cHF,eHF,Vxc,eG0T0)
    call cpu_time(end_evGT)
  
    t_evGT = end_evGT - start_evGT
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for evGT = ',t_evGT,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Information for Monte Carlo calculations
!------------------------------------------------------------------------

  if(doMCMP2 .or. doMinMCMP2) then

!   Print simulation details

    write(*,'(A32)') '----------------------'
    write(*,'(A32,1X,I16)')    'Number of Monte Carlo   steps',nMC
    write(*,'(A32,1X,I16)')    'Number of equilibration steps',nEq
    write(*,'(A32,1X,I16)')    'Number of walkers',nWalk
    write(*,'(A32,1X,F16.10)') 'Initial time step',dt
    write(*,'(A32,1X,I16)')    'Frequency of ouput',nPrint
    write(*,'(A32,1X,I16)')    'Seed for random number generator',iSeed
    write(*,'(A32)') '----------------------'
    write(*,*)

!   Initialize random number generator

    call initialize_random_generator(iSeed)

!------------------------------------------------------------------------
!   Type of weight function
!------------------------------------------------------------------------
!   TrialType = 0 => HF density
!   TrialType = 1 => Custom one-electron function
!------------------------------------------------------------------------

    TrialType = 0
    allocate(cTrial(nBas),gradient(nBas),hessian(nBas,nBas))

  end if
!------------------------------------------------------------------------
! Compute MC-MP2 energy
!------------------------------------------------------------------------

  if(doMCMP2) then

    call cpu_time(start_MCMP2)
!   call MCMP2(doDrift,nBas,nC,nO,nV,cHF,eHF,EcMP2,        &
!              nMC,nEq,nWalk,dt,nPrint,                                  &
!              nShell,CenterShell,TotAngMomShell,KShell,DShell,ExpShell, &
!              Norm,EcMCMP2,Err_EcMCMP2,Var_EcMCMP2)
    call cpu_time(end_MCMP2)

    t_MCMP2 = end_MCMP2 - start_MCMP2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MC-MP2 = ',t_MCMP2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Minimize MC-MP2 variance
!------------------------------------------------------------------------

  if(doMinMCMP2) then

    call cpu_time(start_MinMCMP2)
!   call MinMCMP2(nBas,nEl,nC,nO,nV,cHF,eHF,EcMP2,                              & 
!                 nMC,nEq,nWalk,dt,nPrint,                                  &
!                 nShell,CenterShell,TotAngMomShell,KShell,DShell,ExpShell, & 
!                 TrialType,Norm,cTrial,gradient,hessian)
    call cpu_time(end_MinMCMP2)
    
    t_MinMCMP2 = end_MinMCMP2 - start_MinMCMP2
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for MC-MP2 variance minimization = ',t_MinMCMP2,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Range-separeted GT/GW
!------------------------------------------------------------------------

! if(doGTGW) then

!   ! Read and transform long-range two-electron integrals

!   allocate(ERI_ERF_AO(nBas,nBas,nBas,nBas),ERI_ERF_MO(nBas,nBas,nBas,nBas))
!   call read_LR(nBas,ERI_ERF_AO)

!   call cpu_time(start_AOtoMO)

!   write(*,*)
!   write(*,*) 'AO to MO transformation for long-range ERIs... Please be patient'
!   write(*,*)

!   call AOtoMO_integral_transform(nBas,cHF,ERI_ERF_AO,ERI_ERF_MO)

!   call cpu_time(end_AOtoMO)

!   deallocate(ERI_ERF_AO)

!   t_AOtoMO = end_AOtoMO - start_AOtoMO

!   write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for AO to MO transformation = ',t_AOtoMO,' seconds'
!   write(*,*)

!   ! Long-range G0W0 calculation

!   call cpu_time(start_G0W0)
!   call G0W0(doACFDT,exchange_kernel,doXBS,COHSEX,SOSEX,BSE,TDA_W,TDA,       & 
!             dBSE,dTDA,evDyn,singlet,triplet,linGW,eta_GW, & 
!             nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_ERF_MO,dipole_int_MO,eHF,eG0W0)
!   call cpu_time(end_G0W0)
! 
!   t_G0W0 = end_G0W0 - start_G0W0
!   write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for G0W0 = ',t_G0W0,' seconds'
!   write(*,*)

!   ! Short-range G0T0 calculation

!   ERI_ERF_MO(:,:,:,:) = ERI_MO(:,:,:,:) - ERI_ERF_MO(:,:,:,:)

!   call cpu_time(start_G0T0)
!   call G0T0(doACFDT,exchange_kernel,doXBS,BSE,TDA_W,TDA,dBSE,dTDA,evDyn, &
!             singlet,triplet,linGW,eta_GW,              &  
!             nBas,nC,nO,nV,nR,nS,ENuc,ERHF,ERI_ERF_MO,dipole_int_MO,eHF,eG0T0)
!   call cpu_time(end_G0T0)
! 
!   t_G0T0 = end_G0T0 - start_G0T0
!   write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for G0T0 = ',t_G0T0,' seconds'
!   write(*,*)

!   call matout(nBas,1,(eG0W0+eG0T0-eHF(:,1))*HaToeV)

! end if

!------------------------------------------------------------------------
! Basis set correction
!------------------------------------------------------------------------

  doBas = .false.

  if(doBas) then

    call cpu_time(start_Bas)
    call basis_correction(nBas,nO,nShell,CenterShell,TotAngMomShell,KShell,DShell,ExpShell, &
                          ERI_MO,eHF,cHF,PHF,eG0W0)
    call cpu_time(end_Bas)

    t_Bas = end_Bas - start_Bas
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for basis set correction = ',t_Bas,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! Compute FCI 
!------------------------------------------------------------------------

  if(doFCI) then

    call cpu_time(start_FCI)
    call FCI(nBas,nC,nO,nV,nR,ERI_MO,eHF)
    call cpu_time(end_FCI)

    t_FCI = end_FCI - start_FCI
    write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for FCI = ',t_FCI,' seconds'
    write(*,*)

  end if

!------------------------------------------------------------------------
! End of QuAcK
!------------------------------------------------------------------------

  call cpu_time(end_QuAcK)

  t_QuAcK = end_QuAcK - start_QuAcK
  write(*,'(A65,1X,F9.3,A8)') 'Total CPU time for QuAcK = ',t_QuAcK,' seconds'
  write(*,*)

end program QuAcK