DP_main.f

module DP_main_m

    use type_m
    use omp_lib
    use constants_m
    use f95_precision
    use blas95
    use Semi_Empirical_Parms    , only  : atom
    use parameters_m            , only  : verbose ,                             &
                                          DP_Moment ,                           &
                                          Environ_Type ,                        &
                                          static ,                              &
                                          hole_state ,                          &
                                          excited_state => electron_state        ! for static calculations initial state = excited state
    use Multipole_Routines_m    , only  : rotationmultipoles ,                  &
                                          multipole_messages ,                  &
                                          multipoles1c ,                        &
                                          multipoles2c ,                        &
                                          util_multipoles
    use tuning_m                , only  : eh_tag

!   this is causing dependency problems in compilation
!   use DP_excited_m            , only  : el_hl_StaticDPs


    Real*8 , allocatable , public :: DP_matrix_AO(:,:,:)

    public :: Dipole_Matrix
    public :: Dipole_Moment

    private

    !module variables ...
    logical               , save :: done = .false. , ready = .false.
    integer , allocatable , save :: ija(:) , occupancy(:)
    real*8  , allocatable , save :: xyz(:,:)
    real*8  , allocatable , save :: DP_pack(:,:)


contains
!
!
!
!=====================================================================
 subroutine Dipole_Matrix( system , basis , L_vec , R_vec , Total_DP )
!=====================================================================
implicit none
type(structure)             , intent(inout) :: system
type(STO_basis)             , intent(in)    :: basis(:)
real*8          , optional  , intent(in)    :: L_vec(:,:) , R_vec(:,:)
real*8          , optional  , intent(out)   :: Total_DP(3)

! local variables ...
real*8  :: Sparsity(3)
integer :: NonZero(3) , M_size , i

!----------------------------------------------------------
!       initialize DIPOLE MATRIX M(i,j)[x,y,z]
!       only for QM atoms ...
!----------------------------------------------------------

If( verbose ) Print 153

CALL Util_Multipoles

! size of M matrix ...
M_size = sum( atom(system%AtNo)%DOS , system%QMMM == "QM" )

If( allocated(DP_matrix_AO) ) deallocate( DP_matrix_AO )
allocate( DP_matrix_AO(M_size,M_size,3) )

CALL Build_DIPOLE_Matrix(system,basis)

forall(i=1:3) NonZero(i) = count(DP_matrix_AO(:,:,i) /= D_zero)

Sparsity(:) = dfloat(NonZero(:))/dfloat((M_size**2))

If( verbose ) &
then 
     Print 73, Sparsity
     Print 155
end if

include 'formats.h'

end subroutine Dipole_Matrix
!
!
!
!==================================================================================================
 subroutine Dipole_Moment( system , basis , L_vec , R_vec , AO_bra , AO_ket , Dual_ket , DP_total )
!==================================================================================================
implicit none
type(structure)             , intent(inout) :: system
type(STO_basis)             , intent(in)    :: basis(:)
real*8                      , intent(in)    :: L_vec    (:,:)
real*8                      , intent(in)    :: R_vec    (:,:)
complex*16      , optional  , intent(in)    :: AO_bra   (:,:)
complex*16      , optional  , intent(in)    :: AO_ket   (:,:)
complex*16      , optional  , intent(in)    :: Dual_ket (:,:)
real*8          , optional  , intent(out)   :: DP_total (3)

! local variables ...
integer                       :: xyz, Fermi_state
real*8                        :: Nuclear_DP(3), Electronic_DP(3), hole_DP(3), excited_DP(3), Total_DP(3)
real*8          , allocatable :: R_vector(:,:)
logical         , allocatable :: AO_mask(:)

! local parameters ...
real*8          , parameter   :: Debye_unit = 4.803204d0    ! <== e[C]*d[Angs]*4.803204 = p[Debye]

! define system for DP_Moment calculation ...
allocate( AO_mask(size(basis)) , source = .true. )
AO_mask = merge( basis%DPF , AO_mask , any(basis%DPF) )

! if origin = Center_of_Charge ==> Nuclear_DP = (0,0,0)
CALL Center_of_Charge( system , R_vector )

Nuclear_DP = D_zero

! set MO occupancy ...
Fermi_state = sum( system%Nvalen )/two + mod( sum( system%Nvalen ) , 2 )
If( .not. allocated(occupancy)) then
    allocate(occupancy(Fermi_state), source = 2)
    occupancy(Fermi_state) =  2 - mod( sum( system%Nvalen ) , 2 )
end If

do xyz = 1 , 3

    Electronic_DP(xyz) = DP_Moment_component( xyz , basis , L_vec , R_vec , R_vector , AO_mask , Fermi_state )

end do

!--------------------------------------------------------------------------------------
! Build DP_Moment ...
!--------------------------------------------------------------------------------------

! contribution from the hole and electronic-wavepackets ...
! excited-state case: hole_state /= 0 ...
If( hole_state /= I_zero ) then

    If( static ) then

!        this is causing dependency problems in compilation
!        CALL el_hl_StaticDPs( system , hole_DP , excited_DP )

    else

        If( (eh_tag(1) /= "el") .OR. (eh_tag(2) /= "hl") ) pause ">>> check call to wavepacket_DP in DP_main.f <<<"

!$OMP PARALLEL SECTIONS
        !$OMP SECTION
        hole_DP    =  wavepacket_DP( basis , AO_mask , R_vector , AO_bra(:,2) , AO_ket(:,2) , Dual_ket(:,2) )

        !$OMP SECTION
        excited_DP =  wavepacket_DP( basis , AO_mask , R_vector , AO_bra(:,1) , AO_ket(:,1) , Dual_ket(:,1) )
!$OMP END PARALLEL SECTIONS

    end If

    Electronic_DP = Electronic_DP - hole_DP + excited_DP

end If
! minus sign is due to the negative electron chage ...
Electronic_DP = -Electronic_DP

!================================================
! use classical MM dipole moment, if requested ...
If( Environ_Type == "DP_MM" ) call MM_DP_Moment( system , R_vector , Electronic_DP )
!================================================

Total_DP = ( Nuclear_DP - Electronic_DP ) * Debye_unit
!--------------------------------------------------------------------------------------

If( verbose .AND. present(DP_total) ) &
then
    DP_total = Total_DP
    Print*, " "
    Print*, '>> Dipole Moment done <<'
    Print 154, Total_DP, sqrt(sum(Total_DP*Total_DP))
end if

deallocate(R_vector , AO_mask)

include 'formats.h'

end subroutine Dipole_Moment
!
!
!
!============================================
subroutine Build_DIPOLE_Matrix(system, basis)
!============================================
implicit none
type(structure) , intent(in)    :: system
type(STO_basis) , intent(in)    :: basis(:)

! local variables
real*8  :: expa, expb, Rab
integer :: a , b , ia , ib , ja , jb
integer :: na , la , ma
integer :: nb , lb , mb
integer :: lmult , i , j , k
logical :: atom_not_moved

real*8  , parameter :: tol = 1.d-10
integer , parameter :: mxl = 5 , mxmult = 3 , mxlsup = max(mxl,mxmult)
real*8  , parameter :: cutoff_Angs = 10.d0

real*8 , dimension((mxmult+1)**2,-mxl:mxl,-mxl:mxl)        :: qlm
real*8 , dimension(-mxlsup:mxlsup,-mxlsup:mxlsup,0:mxlsup) :: rl , rl2

lmult = 1 ! <== DIPOLE MOMENT

DP_matrix_AO = D_zero

!$omp parallel do schedule(dynamic,100) default(shared)&
!$omp private(ib,ia,atom_not_moved,Rab,jb,ja,b,a,k,nb,na,lb,la,mb,ma,j,i,expb,expa,rl,rl2,qlm)
do ib = 1 , system%atoms
do ia = 1 , system%atoms

    if( (system%QMMM(ib) /= "QM") .OR. (system%QMMM(ia) /= "QM") ) cycle

    ! if atoms ia and ib remaing fixed => recover DP_matrix_AO ...
    If( ready ) then

        atom_not_moved = all(system%coord(ia,:)==xyz(ia,:)) .AND. all(system%coord(ib,:)==xyz(ib,:))

        Rab = sqrt(sum( (system%coord(ia,:)-system%coord(ib,:)) * (system%coord(ia,:)-system%coord(ib,:)) ) )

        If(Rab > cutoff_Angs) goto 10

        If( atom_not_moved ) then

            do jb = 1 , atom( system%AtNo(ib) )% DOS  ;  b  = system%BasisPointer (ib) + jb
            do ja = 1 , atom( system%AtNo(ia) )% DOS  ;  a  = system%BasisPointer (ia) + ja

                do k = ija(a) , ija(a+1)-1
                    if( ija(k) == b ) DP_Matrix_AO(a,b,:) = DP_pack(k,:)
                end do

            enddo
            enddo

            goto 10

        end if
    end if

    ! if atoms ia and ib move => calculate rotation matrix for the highest l ...
    call RotationMultipoles( system , ia , ib , Rab , lmult , rl , rl2 )

    If(Rab > cutoff_Angs) goto 10

    do jb = 1 , atom(system%AtNo(ib))%DOS  ;  b = system%BasisPointer(ib) + jb
    do ja = 1 , atom(system%AtNo(ia))%DOS  ;  a = system%BasisPointer(ia) + ja

        na = basis(a)%n ;   la = basis(a)%l ;   ma = basis(a)%m
        nb = basis(b)%n ;   lb = basis(b)%l ;   mb = basis(b)%m

        CALL Multipole_Messages(na,nb,la,lb)

!----------------------------------------------------------------------------------------------------
!       sum over zeta coefficients
        do i = 1 , basis(a)%Nzeta
        do j = 1 , basis(b)%Nzeta

            expa = basis(a)%zeta(i)
            expb = basis(b)%zeta(j)

            if( ia==ib ) then

!               CALLS THE SUBROUTINE FOR THE MULTIPOLES OF ONE-CENTER DISTRIBUTIONS

                qlm = 0.d0

                call multipoles1c(na, la, expa, nb, lb, expb, lmult, qlm)

            else

!               CALLS THE SUBROUTINE FOR THE MULTIPOLES OF TWO-CENTER DISTRIBUTIONS

                qlm = 0.d0

                call multipoles2c(na, la, expa, nb, lb, expb, Rab, lmult, rl, qlm)

            end if

!           p_x(a,b)
            DP_matrix_AO(a,b,1) = DP_matrix_AO(a,b,1) + basis(a)%coef(i)*basis(b)%coef(j)*qlm(4,ma,mb)
!           p_y(a,b)
            DP_matrix_AO(a,b,2) = DP_matrix_AO(a,b,2) + basis(a)%coef(i)*basis(b)%coef(j)*qlm(2,ma,mb)
!           p_z(a,b)
            DP_matrix_AO(a,b,3) = DP_matrix_AO(a,b,3) + basis(a)%coef(i)*basis(b)%coef(j)*qlm(3,ma,mb)

        end do
        end do
!----------------------------------------------------------------------------------------------------

    enddo
    enddo
10 end do
end do
!$omp end parallel do

! save DP_Matrix_AO for reuse ...
If( (.NOT. static) .AND. (.NOT. done) ) then

    allocate( xyz , source = system%coord)

    CALL sprsin( DP_Matrix_AO )

    done  = .true.
    ready = .true.

End If

end subroutine Build_DIPOLE_Matrix
!
!
!
!=================================================================================================
function DP_Moment_component( xyz , basis , L_vec , R_vec , R_vector , AO_mask , Fermi_state)
!=================================================================================================
implicit none
integer                  , intent(in) :: xyz
type(STO_basis)          , intent(in) :: basis    (:)
real*8                   , intent(in) :: L_vec    (:,:)
real*8                   , intent(in) :: R_vec    (:,:)
real*8                   , intent(in) :: R_vector (:,:)
logical                  , intent(in) :: AO_mask  (:)
integer                  , intent(in) :: Fermi_state

real*8 :: DP_Moment_component

! local variables ...
real*8     , allocatable :: a(:,:), b(:,:)
real*8     , allocatable :: origin_Dependent   (:)
real*8     , allocatable :: origin_Independent (:)
integer                  :: i , states , n_basis

! Electronic dipole
n_basis = size(basis)

allocate( a(n_basis,n_basis)              , source = D_zero )
allocate( b(n_basis,n_basis)              , source = D_zero )
allocate( origin_Dependent  (Fermi_state) )
allocate( origin_Independent(Fermi_state) )

! origin dependent DP = sum{C_dagger * vec{R} * S_ij * C}
do states = 1 , Fermi_state
    do concurrent (i=1:n_basis)
        a(states,i) = L_vec(states,i) * R_vector(basis(i)%atom,xyz)
    end do
    origin_Dependent(states) = occupancy(states) * sum( a(states,:)*R_vec(:,states) , AO_mask )
end do

! origin independent DP = sum{C_dagger * vec{DP_matrix_AO(i,j)} * C}
b = DP_matrix_AO(:,:,xyz)
CALL gemm( L_vec , b , a , 'N' , 'N' , D_one , D_zero )

forall( states=1:Fermi_state ) origin_Independent(states) = occupancy(states) * sum( a(states,:)*L_vec(states,:) , AO_mask )

deallocate( a , b )

! contribution from the valence states ...
DP_Moment_component = sum( origin_Dependent + origin_Independent )

deallocate( origin_Dependent , origin_Independent )

end function DP_Moment_component
!
!
!
!=============================================================================
 pure function wavepacket_DP( basis , mask , R_vector , bra , ket , Dual_ket )
!=============================================================================
implicit none
type(STO_basis) , intent(in)    :: basis(:)
logical         , intent(in)    :: mask(:)
real*8          , intent(in)    :: R_vector(:,:)
complex*16      , intent(in)    :: bra(:)
complex*16      , intent(in)    :: ket(:)
complex*16      , intent(in)    :: Dual_ket(:)
real*8                          :: wavepacket_DP(3)

! local variables ...
integer                         :: i, xyz, n_basis
complex*16      , allocatable   :: a(:), b(:,:)
type(R3_vector)                 :: origin_Dependent, origin_Independent

n_basis = size(basis)

allocate( a(n_basis)         , source = C_zero )
allocate( b(n_basis,n_basis) , source = C_zero )

do xyz = 1 , 3

        ! origin dependent DP = sum{bra * vec{R} * S_ij * ket}

        forall( i=1:n_basis ) a(i) = bra(i) * R_vector(basis(i)%atom,xyz)

        origin_Dependent%DP(xyz) = real( sum( a(:)*Dual_ket(:) , mask ) )

        ! origin independent DP = sum{bra * vec{DP_matrix_AO(i,j)} * ket}

        b = DP_matrix_AO(:,:,xyz)

        CALL gemv( b , ket , a , C_one , C_zero )

        origin_Independent%DP(xyz) = real( sum( bra(:)*a(:) , mask ) )

end do

wavepacket_DP = origin_Dependent%DP + origin_Independent%DP

deallocate( a , b )

end function wavepacket_DP
!
!
!
!==============================================================
 subroutine MM_DP_Moment( system , R_vector , MM_DP )
!==============================================================
use MD_read_m , only : MM_Atom => atom
implicit none
type(structure) , intent(in)  :: system
real*8          , intent(in)  :: R_vector(:,:)
real*8          , intent(out) :: MM_DP(3)

! local variables ...
integer :: xyz

! classical electronic_DP ...  
do xyz = 1,3 
   MM_DP(xyz) = sum( MM_atom(:)%MM_charge * R_vector(:,xyz) , system%DPF == .true. )
   end do

end subroutine MM_DP_Moment 
!
!
!
!===========================================
 subroutine Center_of_Charge( a , R_vector )
!===========================================
implicit none
type(structure)                 , intent(inout) :: a
real*8          , allocatable   , intent(out)   :: R_vector(:,:)

! local variables ...
integer               :: i , j
real*8                :: total_valence
real*8  , allocatable :: Qi_Ri(:,:)
logical , allocatable :: mask(:)

! define system for DP_Moment calculation ...
allocate( mask(a%atoms) , source = .true. )
mask = merge( mask , a%DPF , count(a%DPF) == I_zero )

! sum_i = (q_i * vec{r}_i) / sum_i q_i ...

allocate( Qi_Ri(a%atoms,3) , source = D_zero )

forall( j=1:3 , i=1:a%atoms , mask(i) ) Qi_Ri(i,j) = atom(a%AtNo(i))%Nvalen * a%coord(i,j)

total_valence = sum( atom(a%AtNo(:))%Nvalen, mask )

forall(j=1:3) a%Center_of_Charge(j) = sum( Qi_Ri(:,j) , mask ) / total_valence

! atomic positions measured from the Center of Charge
allocate( R_vector(a%atoms,3) , source = D_zero )
forall( j=1:3 , i=1:a%atoms , mask(i) ) R_vector(i,j) = a%coord(i,j) - a%Center_of_Charge(j)

deallocate( Qi_Ri , mask )

end subroutine Center_of_Charge
!
!
!
!=================================
 subroutine sprsin( DP_Matrix_AO )
!=================================
implicit none
real*8 , intent(in) :: DP_Matrix_AO(:,:,:)

!=====================================================================
! converts a matrix a(1:n,1:n,1:3) with physical dimension np into
! row-indexed sparse storage mode. Only elements of a with magnitude >=
! thresh are retained. Output is in two linear arrays with physical
! dimension nmax (an input parameter): sa(1:) contains array lines,
! indexed by ija(1:). The logical sizes of sa and ija on output are
! both  ija(ija(1)-1)-1
!=====================================================================

!local variables ...
integer               :: i , j , k , n , length, nnz
real*8                :: thresh = mid_prec
integer , allocatable :: tmp_ij(:)
real*8  , allocatable :: tmp_DP(:,:)

!local parameters ...
integer  :: nmax = 100000000

n = size( DP_Matrix_AO(:,1,1) )

allocate( tmp_ij(nmax  ) )
allocate( tmp_DP(nmax,3) , source=D_zero )

      DO 11 j = 1 , n
         tmp_DP(j,:) = DP_Matrix_AO(j,j,:)
11    END DO
      tmp_ij(1) = n + 2
      k = n + 1
      DO 13 i = 1 , n
         DO 12 j = 1 , n
            IF( any( abs(DP_Matrix_AO(i,j,:)) >= thresh ) ) then
              IF(i /= j) then
                k = k + 1
                IF(k > nmax) pause 'nmax too small in sprsin'
                tmp_DP(k,:) = DP_Matrix_AO(i,j,:)
                tmp_ij(k) = j
              END IF
            END IF
12       END DO
         tmp_ij(i+1) = k + 1
13    END DO

length = tmp_ij( tmp_ij(1) - 1 ) - 1             ! <== physical size of DP_pack and ija
nnz    = tmp_ij( tmp_ij(1) - 1 ) - 2             ! <== number of nonzero elements

allocate( DP_pack(length,3) )
forall(i=1:3) DP_pack(:length,i) = tmp_DP(:length,i)  

allocate( ija (length) )
ija(:length) = tmp_ij(:length)  

deallocate( tmp_DP , tmp_IJ )

END subroutine sprsin
!
!
!
end module DP_main_m