OOPSE/libmdtools/calc_eam.F90

module eam
  use definitions, ONLY : DP,default_error
  use simulation
  use force_globals
  use status
  use atype_module
  use Vector_class
#ifdef IS_MPI
  use mpiSimulation
#endif
  implicit none
  PRIVATE


  logical, save :: EAM_FF_initialized = .false.
  integer, save :: EAM_Mixing_Policy
  real(kind = dp), save :: EAM_rcut
  logical, save :: haveRcut = .false.

  character(len = statusMsgSize) :: errMesg
  integer :: eam_err

  character(len = 200) :: errMsg
  character(len=*), parameter :: RoutineName =  "EAM MODULE"
!! Logical that determines if eam arrays should be zeroed
  logical :: cleanme = .true.
  logical :: nmflag  = .false.

 
  type, private :: EAMtype
     integer           :: eam_atype       
     real( kind = DP ) :: eam_dr          
     integer           :: eam_nr           
     integer           :: eam_nrho          
     real( kind = DP ) :: eam_lattice        
     real( kind = DP ) :: eam_drho      
     real( kind = DP ) :: eam_rcut     
     integer           :: eam_atype_map
     
     real( kind = DP ), pointer, dimension(:) :: eam_rvals        => null()
     real( kind = DP ), pointer, dimension(:) :: eam_rhovals      => null()
     real( kind = DP ), pointer, dimension(:) :: eam_F_rho        => null()
     real( kind = DP ), pointer, dimension(:) :: eam_Z_r          => null()
     real( kind = DP ), pointer, dimension(:) :: eam_rho_r        => null()
     real( kind = DP ), pointer, dimension(:) :: eam_phi_r        => null()
     real( kind = DP ), pointer, dimension(:) :: eam_F_rho_pp     => null()
     real( kind = DP ), pointer, dimension(:) :: eam_Z_r_pp       => null()
     real( kind = DP ), pointer, dimension(:) :: eam_rho_r_pp     => null()
     real( kind = DP ), pointer, dimension(:) :: eam_phi_r_pp     => null()
  end type EAMtype


  !! Arrays for derivatives used in force calculation
  real( kind = dp), dimension(:), allocatable :: frho
  real( kind = dp), dimension(:), allocatable :: rho

  real( kind = dp), dimension(:), allocatable :: dfrhodrho
  real( kind = dp), dimension(:), allocatable :: d2frhodrhodrho


!! Arrays for MPI storage
#ifdef IS_MPI
  real( kind = dp),save, dimension(:), allocatable :: dfrhodrho_col
  real( kind = dp),save, dimension(:), allocatable :: dfrhodrho_row
  real( kind = dp),save, dimension(:), allocatable :: frho_row
  real( kind = dp),save, dimension(:), allocatable :: frho_col
  real( kind = dp),save, dimension(:), allocatable :: rho_row
  real( kind = dp),save, dimension(:), allocatable :: rho_col
  real( kind = dp),save, dimension(:), allocatable :: d2frhodrhodrho_col
  real( kind = dp),save, dimension(:), allocatable :: d2frhodrhodrho_row
#endif

  type, private :: EAMTypeList
     integer           :: n_eam_types = 0
     integer           :: currentAddition = 0
     
     type (EAMtype), pointer  :: EAMParams(:) => null()
  end type EAMTypeList


  type (eamTypeList), save :: EAMList

  !! standard eam stuff  


  public :: init_EAM_FF
  public :: setCutoffEAM
  public :: do_eam_pair
  public :: newEAMtype
  public :: calc_eam_prepair_rho
  public :: calc_eam_preforce_Frho
  public :: clean_EAM

contains


  subroutine newEAMtype(lattice_constant,eam_nrho,eam_drho,eam_nr,&
       eam_dr,rcut,eam_Z_r,eam_rho_r,eam_F_rho,&
       eam_ident,status)
    real (kind = dp )                      :: lattice_constant
    integer                                :: eam_nrho
    real (kind = dp )                      :: eam_drho
    integer                                :: eam_nr
    real (kind = dp )                      :: eam_dr
    real (kind = dp )                      :: rcut
    real (kind = dp ), dimension(eam_nr)   :: eam_Z_r
    real (kind = dp ), dimension(eam_nr)   :: eam_rho_r
    real (kind = dp ), dimension(eam_nrho) :: eam_F_rho
    integer                                :: eam_ident
    integer                                :: status

    integer                                :: nAtypes
    integer                                :: maxVals
    integer                                :: alloc_stat
    integer                                :: current
    integer,pointer                        :: Matchlist(:) => null()

    status = 0


    !! Assume that atypes has already been set and get the total number of types in atypes
    !! Also assume that every member of atypes is a EAM model.
   

    ! check to see if this is the first time into 
    if (.not.associated(EAMList%EAMParams)) then
       call getMatchingElementList(atypes, "is_EAM", .true., nAtypes, MatchList)
       EAMList%n_eam_types = nAtypes
       allocate(EAMList%EAMParams(nAtypes))
    end if

    EAMList%currentAddition = EAMList%currentAddition + 1
    current = EAMList%currentAddition
    

    call allocate_EAMType(eam_nrho,eam_nr,EAMList%EAMParams(current),stat=alloc_stat)
    if (alloc_stat /= 0) then
       status = -1
       return
    end if

    ! this is a possible bug, we assume a correspondence between the vector atypes and
    ! EAMAtypes
      
    EAMList%EAMParams(current)%eam_atype    = eam_ident
    EAMList%EAMParams(current)%eam_lattice  = lattice_constant
    EAMList%EAMParams(current)%eam_nrho     = eam_nrho
    EAMList%EAMParams(current)%eam_drho     = eam_drho
    EAMList%EAMParams(current)%eam_nr       = eam_nr
    EAMList%EAMParams(current)%eam_dr       = eam_dr
    EAMList%EAMParams(current)%eam_rcut     = rcut
    EAMList%EAMParams(current)%eam_Z_r      = eam_Z_r
    EAMList%EAMParams(current)%eam_rho_r    = eam_rho_r
    EAMList%EAMParams(current)%eam_F_rho    = eam_F_rho

  end subroutine newEAMtype


  subroutine init_EAM_FF(status)
    integer :: status
    integer :: i,j
    real(kind=dp) :: current_rcut_max
    integer :: alloc_stat
    integer :: number_r, number_rho


    status = 0
    if (EAMList%currentAddition == 0) then
       call handleError("init_EAM_FF","No members in EAMList")
       status = -1
       return
    end if

 
       do i = 1, EAMList%currentAddition

! Build array of r values

          do j = 1,EAMList%EAMParams(i)%eam_nr
             EAMList%EAMParams(i)%eam_rvals(j) = &
                  real(j-1,kind=dp)* &
                  EAMList%EAMParams(i)%eam_dr
              end do
! Build array of rho values
          do j = 1,EAMList%EAMParams(i)%eam_nrho
             EAMList%EAMParams(i)%eam_rhovals(j) = &
                  real(j-1,kind=dp)* &
                  EAMList%EAMParams(i)%eam_drho
          end do
          ! convert from eV to kcal / mol:
          EAMList%EAMParams(i)%eam_F_rho = EAMList%EAMParams(i)%eam_F_rho * 23.06054E0_DP

          ! precompute the pair potential and get it into kcal / mol:
          EAMList%EAMParams(i)%eam_phi_r(1) = 0.0E0_DP
          do j = 2, EAMList%EAMParams(i)%eam_nr
             EAMList%EAMParams(i)%eam_phi_r(j) = (EAMList%EAMParams(i)%eam_Z_r(j)**2)/EAMList%EAMParams(i)%eam_rvals(j)
             EAMList%EAMParams(i)%eam_phi_r(j) =  EAMList%EAMParams(i)%eam_phi_r(j)*331.999296E0_DP
          enddo
       end do
       

       do i = 1,  EAMList%currentAddition
          number_r   = EAMList%EAMParams(i)%eam_nr
          number_rho = EAMList%EAMParams(i)%eam_nrho
          
          call eam_spline(number_r, EAMList%EAMParams(i)%eam_rvals, &
               EAMList%EAMParams(i)%eam_rho_r, &
               EAMList%EAMParams(i)%eam_rho_r_pp, &
               0.0E0_DP, 0.0E0_DP, 'N')
          call eam_spline(number_r, EAMList%EAMParams(i)%eam_rvals, &
               EAMList%EAMParams(i)%eam_Z_r, &
               EAMList%EAMParams(i)%eam_Z_r_pp, &
               0.0E0_DP, 0.0E0_DP, 'N')
          call eam_spline(number_rho, EAMList%EAMParams(i)%eam_rhovals, &
               EAMList%EAMParams(i)%eam_F_rho, &
               EAMList%EAMParams(i)%eam_F_rho_pp, &
               0.0E0_DP, 0.0E0_DP, 'N')
          call eam_spline(number_r, EAMList%EAMParams(i)%eam_rvals, &
               EAMList%EAMParams(i)%eam_phi_r, &
               EAMList%EAMParams(i)%eam_phi_r_pp, &
               0.0E0_DP, 0.0E0_DP, 'N')
       enddo


!       current_rcut_max = EAMList%EAMParams(1)%eam_rcut
       !! find the smallest rcut for any eam atype
!       do i = 2, EAMList%currentAddition 
!          current_rcut_max =max(current_rcut_max,EAMList%EAMParams(i)%eam_rcut)
!       end do

!       EAM_rcut = current_rcut_max
!       EAM_rcut_orig = current_rcut_max
!       do i = 1, EAMList%currentAddition
!          EAMList%EAMParam(i)s%eam_atype_map(eam_atype(i)) = i
!       end do
       !! Allocate arrays for force calculation
      
       call allocateEAM(alloc_stat)
       if (alloc_stat /= 0 ) then
          write(*,*) "allocateEAM failed"
          status = -1
          return
       endif
    
  end subroutine init_EAM_FF

!! routine checks to see if array is allocated, deallocates array if allocated
!! and then creates the array to the required size
  subroutine allocateEAM(status)
    integer, intent(out) :: status

    integer :: nlocal
#ifdef IS_MPI
    integer :: nrow
    integer :: ncol
#endif
    integer :: alloc_stat


    nlocal = getNlocal()
    status = 0
#ifdef IS_MPI
    nrow = getNrow(plan_row)
    ncol = getNcol(plan_col)
#endif

    if (allocated(frho)) deallocate(frho)
    allocate(frho(nlocal),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(rho)) deallocate(rho)
    allocate(rho(nlocal),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if

    if (allocated(dfrhodrho)) deallocate(dfrhodrho)
    allocate(dfrhodrho(nlocal),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if

    if (allocated(d2frhodrhodrho)) deallocate(d2frhodrhodrho)
    allocate(d2frhodrhodrho(nlocal),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    
#ifdef IS_MPI

    if (allocated(frho_row)) deallocate(frho_row)
    allocate(frho_row(nrow),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(rho_row)) deallocate(rho_row)
    allocate(rho_row(nrow),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(dfrhodrho_row)) deallocate(dfrhodrho_row)
    allocate(dfrhodrho_row(nrow),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(d2frhodrhodrho_row)) deallocate(d2frhodrhodrho_row)
    allocate(d2frhodrhodrho_row(nrow),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if


! Now do column arrays

    if (allocated(frho_col)) deallocate(frho_col)
    allocate(frho_col(ncol),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(rho_col)) deallocate(rho_col)
    allocate(rho_col(ncol),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(dfrhodrho_col)) deallocate(dfrhodrho_col)
    allocate(dfrhodrho_col(ncol),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
    if (allocated(d2frhodrhodrho_col)) deallocate(d2frhodrhodrho_col)
    allocate(d2frhodrhodrho_col(ncol),stat=alloc_stat)
    if (alloc_stat /= 0) then 
       status = -1
       return
    end if
  
#endif

  end subroutine allocateEAM

!! C sets rcut to be the largest cutoff of any atype 
!! present in this simulation. Doesn't include all atypes
!! sim knows about, just those in the simulation.
  subroutine setCutoffEAM(rcut, status)
    real(kind=dp) :: rcut
    integer :: status
    status = 0

    EAM_rcut = rcut

  end subroutine setCutoffEAM


  subroutine clean_EAM()
  
   ! clean non-IS_MPI first
    frho = 0.0_dp
    rho  = 0.0_dp
    dfrhodrho = 0.0_dp
! clean MPI if needed
#ifdef IS_MPI
    frho_row = 0.0_dp
    frho_col = 0.0_dp
    rho_row  = 0.0_dp
    rho_col  = 0.0_dp
    dfrhodrho_row = 0.0_dp
    dfrhodrho_col = 0.0_dp
#endif
  end subroutine clean_EAM


  subroutine allocate_EAMType(eam_n_rho,eam_n_r,thisEAMType,stat)
    integer, intent(in)          :: eam_n_rho
    integer, intent(in)          :: eam_n_r
    type (EAMType)               :: thisEAMType
    integer, optional   :: stat
    integer             :: alloc_stat


    if (present(stat)) stat = 0
    
    allocate(thisEAMType%eam_rvals(eam_n_r),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_rhovals(eam_n_rho),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_F_rho(eam_n_rho),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_Z_r(eam_n_r),stat=alloc_stat)        
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_rho_r(eam_n_r),stat=alloc_stat)      
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_phi_r(eam_n_r),stat=alloc_stat)      
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_F_rho_pp(eam_n_rho),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_Z_r_pp(eam_n_r),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_rho_r_pp(eam_n_r),stat=alloc_stat)   
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
    allocate(thisEAMType%eam_phi_r_pp(eam_n_r),stat=alloc_stat)
    if (alloc_stat /= 0 ) then
       if (present(stat)) stat = -1
       return
    end if
       

  end subroutine allocate_EAMType


  subroutine deallocate_EAMType(thisEAMType)
    type (EAMtype), pointer :: thisEAMType

    ! free Arrays in reverse order of allocation...
    deallocate(thisEAMType%eam_phi_r_pp)      
    deallocate(thisEAMType%eam_rho_r_pp)   
    deallocate(thisEAMType%eam_Z_r_pp)   
    deallocate(thisEAMType%eam_F_rho_pp)   
    deallocate(thisEAMType%eam_phi_r)      
    deallocate(thisEAMType%eam_rho_r)      
    deallocate(thisEAMType%eam_Z_r)   
    deallocate(thisEAMType%eam_F_rho)
    deallocate(thisEAMType%eam_rhovals)
    deallocate(thisEAMType%eam_rvals)
   
  end subroutine deallocate_EAMType

!! Calculates rho_r
  subroutine calc_eam_prepair_rho(atom1,atom2,d,r,rijsq)
    integer :: atom1,atom2
    real(kind = dp), dimension(3) :: d
    real(kind = dp), intent(inout)               :: r
    real(kind = dp), intent(inout)               :: rijsq
    ! value of electron density rho do to atom i at atom j
    real(kind = dp) :: rho_i_at_j
    ! value of electron density rho do to atom j at atom i
    real(kind = dp) :: rho_j_at_i

    ! we don't use the derivatives, dummy variables
    real( kind = dp) :: drho,d2rho
    integer :: eam_err
   
    integer :: myid_atom1
    integer :: myid_atom2

! check to see if we need to be cleaned at the start of a force loop
      

#ifdef IS_MPI
    myid_atom1 = atid_Row(atom1)
    myid_atom2 = atid_Col(atom2)
#else
    myid_atom1 = atid(atom1)
    myid_atom2 = atid(atom2)
#endif

    if (r.lt.EAMList%EAMParams(myid_atom1)%eam_rcut) then


       call eam_splint(EAMList%EAMParams(myid_atom1)%eam_nr, &
            EAMList%EAMParams(myid_atom1)%eam_rvals, &
            EAMList%EAMParams(myid_atom1)%eam_rho_r, &
            EAMList%EAMParams(myid_atom1)%eam_rho_r_pp, &
            r, rho_i_at_j,drho,d2rho)


#ifdef  IS_MPI
       rho_col(atom2) = rho_col(atom2) + rho_i_at_j
#else
       rho(atom2) = rho(atom2) + rho_i_at_j
#endif
!       write(*,*) atom1,atom2,r,rho_i_at_j
       endif

       if (r.lt.EAMList%EAMParams(myid_atom2)%eam_rcut) then
          call eam_splint(EAMList%EAMParams(myid_atom2)%eam_nr, &
               EAMList%EAMParams(myid_atom2)%eam_rvals, &
               EAMList%EAMParams(myid_atom2)%eam_rho_r, &
               EAMList%EAMParams(myid_atom2)%eam_rho_r_pp, &
               r, rho_j_at_i,drho,d2rho)


#ifdef  IS_MPI
          rho_row(atom1) = rho_row(atom1) + rho_j_at_i
#else
          rho(atom1) = rho(atom1) + rho_j_at_i
#endif
       endif


  end subroutine calc_eam_prepair_rho


  !! Calculate the functional F(rho) for all local atoms
  subroutine calc_eam_preforce_Frho(nlocal,pot)
    integer :: nlocal
    real(kind=dp) :: pot
    integer :: i,j
    integer :: atom
    real(kind=dp) :: U,U1,U2
    integer :: atype1
    integer :: me
    integer :: n_rho_points

  
    cleanme = .true.
    !! Scatter the electron density from  pre-pair calculation back to local atoms
#ifdef IS_MPI
    call scatter(rho_row,rho,plan_row,eam_err)
    if (eam_err /= 0 ) then
      write(errMsg,*) " Error scattering rho_row into rho"
      call handleError(RoutineName,errMesg)
   endif       
    call scatter(rho_col,rho,plan_col,eam_err)
    if (eam_err /= 0 ) then
      write(errMsg,*) " Error scattering rho_col into rho"
      call handleError(RoutineName,errMesg)
   endif
#endif


!! Calculate F(rho) and derivative 
    do atom = 1, nlocal
       me = atid(atom)
       n_rho_points = EAMList%EAMParams(me)%eam_nrho
       !  Check to see that the density is not greater than the larges rho we have calculated
       if (rho(atom) < EAMList%EAMParams(me)%eam_rhovals(n_rho_points)) then
          call eam_splint(n_rho_points, &
               EAMList%EAMParams(me)%eam_rhovals, &
               EAMList%EAMParams(me)%eam_f_rho, &
               EAMList%EAMParams(me)%eam_f_rho_pp, &
               rho(atom), & ! Actual Rho
               u, u1, u2)
       else 
          ! Calculate F(rho with the largest available rho value
          call eam_splint(n_rho_points, &
               EAMList%EAMParams(me)%eam_rhovals, &
               EAMList%EAMParams(me)%eam_f_rho, &
               EAMList%EAMParams(me)%eam_f_rho_pp, &
               EAMList%EAMParams(me)%eam_rhovals(n_rho_points), & ! Largest rho
               u,u1,u2)
       end if


       frho(atom) = u
       dfrhodrho(atom) = u1
       d2frhodrhodrho(atom) = u2
       pot = pot + u

    enddo

   
#ifdef IS_MPI
    !! communicate f(rho) and derivatives back into row and column arrays
    call gather(frho,frho_row,plan_row, eam_err)
    if (eam_err /=  0) then
       call handleError("cal_eam_forces()","MPI gather frho_row failure")
    endif
    call gather(dfrhodrho,dfrhodrho_row,plan_row, eam_err)
    if (eam_err /=  0) then
       call handleError("cal_eam_forces()","MPI gather dfrhodrho_row failure")
    endif
    call gather(frho,frho_col,plan_col, eam_err)
    if (eam_err /=  0) then
       call handleError("cal_eam_forces()","MPI gather frho_col failure")
    endif
    call gather(dfrhodrho,dfrhodrho_col,plan_col, eam_err)
    if (eam_err /=  0) then
       call handleError("cal_eam_forces()","MPI gather dfrhodrho_col failure")
    endif


    if (nmflag) then
       call gather(d2frhodrhodrho,d2frhodrhodrho_row,plan_row)
       call gather(d2frhodrhodrho,d2frhodrhodrho_col,plan_col)
    endif
#endif

  
  end subroutine calc_eam_preforce_Frho


  !! Does EAM pairwise Force calculation.  
  subroutine do_eam_pair(atom1,atom2,d,rij,r2,pot,f,do_pot,do_stress)
    !Arguments    
    integer, intent(in) ::  atom1, atom2
    real( kind = dp ), intent(in) :: rij, r2
    real( kind = dp ) :: pot
    real( kind = dp ), dimension(3,getNlocal()) :: f
    real( kind = dp ), intent(in), dimension(3) :: d
    logical, intent(in) :: do_pot, do_stress
    
    real( kind = dp ) :: drdx,drdy,drdz
    real( kind = dp ) :: d2
    real( kind = dp ) :: phab,pha,dvpdr,d2vpdrdr
    real( kind = dp ) :: rha,drha,d2rha, dpha
    real( kind = dp ) :: rhb,drhb,d2rhb, dphb
    real( kind = dp ) :: dudr
    real( kind = dp ) :: rci,rcj
    real( kind = dp ) :: drhoidr,drhojdr
    real( kind = dp ) :: d2rhoidrdr
    real( kind = dp ) :: d2rhojdrdr
    real( kind = dp ) :: Fx,Fy,Fz
    real( kind = dp ) :: r,d2pha,phb,d2phb

    integer :: id1,id2
    integer  :: mytype_atom1
    integer  :: mytype_atom2

!Local Variables
    
   ! write(*,*) "Frho: ", Frho(atom1)

    phab = 0.0E0_DP
    dvpdr = 0.0E0_DP
    d2vpdrdr = 0.0E0_DP

    if (rij .lt. EAM_rcut) then
#ifdef IS_MPI
!!!!! FIX ME
       mytype_atom1 = atid_row(atom1)
#else
       mytype_atom1 = atid(atom1)
#endif
       
       drdx = d(1)/rij
       drdy = d(2)/rij
       drdz = d(3)/rij
       

       call eam_splint(EAMList%EAMParams(mytype_atom1)%eam_nr, &
               EAMList%EAMParams(mytype_atom1)%eam_rvals, &
               EAMList%EAMParams(mytype_atom1)%eam_rho_r, &
               EAMList%EAMParams(mytype_atom1)%eam_rho_r_pp, &
               rij, rha,drha,d2rha)

       !! Calculate Phi(r) for atom1.
       call eam_splint(EAMList%EAMParams(mytype_atom1)%eam_nr, &
               EAMList%EAMParams(mytype_atom1)%eam_rvals, &
               EAMList%EAMParams(mytype_atom1)%eam_phi_r, &
               EAMList%EAMParams(mytype_atom1)%eam_phi_r_pp, &
               rij, pha,dpha,d2pha)


! get cutoff for atom 1
       rci = EAMList%EAMParams(mytype_atom1)%eam_rcut
#ifdef IS_MPI
       mytype_atom2 = atid_col(atom2)
#else
       mytype_atom2 = atid(atom2)
#endif

       ! Calculate rho,drho and d2rho for atom1
       call eam_splint(EAMList%EAMParams(mytype_atom2)%eam_nr, &
               EAMList%EAMParams(mytype_atom2)%eam_rvals, &
               EAMList%EAMParams(mytype_atom2)%eam_rho_r, &
               EAMList%EAMParams(mytype_atom2)%eam_rho_r_pp, &
               rij, rhb,drhb,d2rhb)

       !! Calculate Phi(r) for atom2.
       call eam_splint(EAMList%EAMParams(mytype_atom2)%eam_nr, &
               EAMList%EAMParams(mytype_atom2)%eam_rvals, &
               EAMList%EAMParams(mytype_atom2)%eam_phi_r, &
               EAMList%EAMParams(mytype_atom2)%eam_phi_r_pp, &
               rij, phb,dphb,d2phb)


! get type specific cutoff for atom 2
       rcj = EAMList%EAMParams(mytype_atom1)%eam_rcut


       if (rij.lt.rci) then 
          phab = phab + 0.5E0_DP*(rhb/rha)*pha
          dvpdr = dvpdr + 0.5E0_DP*((rhb/rha)*dpha + &
               pha*((drhb/rha) - (rhb*drha/rha/rha)))
          d2vpdrdr = d2vpdrdr + 0.5E0_DP*((rhb/rha)*d2pha + &
               2.0E0_DP*dpha*((drhb/rha) - (rhb*drha/rha/rha)) + &
               pha*((d2rhb/rha) - 2.0E0_DP*(drhb*drha/rha/rha) + &
               (2.0E0_DP*rhb*drha*drha/rha/rha/rha) - (rhb*d2rha/rha/rha)))
       endif
       

       if (rij.lt.rcj) then
          phab = phab + 0.5E0_DP*(rha/rhb)*phb
          dvpdr = dvpdr + 0.5E0_DP*((rha/rhb)*dphb + &
               phb*((drha/rhb) - (rha*drhb/rhb/rhb)))
          d2vpdrdr = d2vpdrdr + 0.5E0_DP*((rha/rhb)*d2phb + &
               2.0E0_DP*dphb*((drha/rhb) - (rha*drhb/rhb/rhb)) + &
               phb*((d2rha/rhb) - 2.0E0_DP*(drha*drhb/rhb/rhb) + &
               (2.0E0_DP*rha*drhb*drhb/rhb/rhb/rhb) - (rha*d2rhb/rhb/rhb)))
       endif
       
       drhoidr = drha
       drhojdr = drhb

       d2rhoidrdr = d2rha
       d2rhojdrdr = d2rhb


#ifdef IS_MPI
       dudr = drhojdr*dfrhodrho_row(atom1)+drhoidr*dfrhodrho_col(atom2) &
            + dvpdr

#else
       dudr = drhojdr*dfrhodrho(atom1)+drhoidr*dfrhodrho(atom2) &
            + dvpdr
      ! write(*,*) "Atom1,Atom2, dfrhodrho(atom1) dfrhodrho(atom2): ", atom1,atom2,dfrhodrho(atom1),dfrhodrho(atom2)
#endif

       fx = dudr * drdx
       fy = dudr * drdy
       fz = dudr * drdz


#ifdef IS_MPI
       if (do_pot) then
          pot_Row(atom1) = pot_Row(atom1) + phab*0.5
          pot_Col(atom2) = pot_Col(atom2) + phab*0.5
       end if

       f_Row(1,atom1) = f_Row(1,atom1) + fx
       f_Row(2,atom1) = f_Row(2,atom1) + fy
       f_Row(3,atom1) = f_Row(3,atom1) + fz
       
       f_Col(1,atom2) = f_Col(1,atom2) - fx
       f_Col(2,atom2) = f_Col(2,atom2) - fy
       f_Col(3,atom2) = f_Col(3,atom2) - fz
#else

       if(do_pot) then
          pot = pot + phab
       end if

       f(1,atom1) = f(1,atom1) + fx
       f(2,atom1) = f(2,atom1) + fy
       f(3,atom1) = f(3,atom1) + fz
       
       f(1,atom2) = f(1,atom2) - fx
       f(2,atom2) = f(2,atom2) - fy
       f(3,atom2) = f(3,atom2) - fz
#endif
       
       if (nmflag) then

          drhoidr = drha
          drhojdr = drhb
          d2rhoidrdr = d2rha
          d2rhojdrdr = d2rhb

#ifdef IS_MPI
          d2 = d2vpdrdr + &
               d2rhoidrdr*dfrhodrho_col(atom2) + &
               d2rhojdrdr*dfrhodrho_row(atom1) + &
               drhoidr*drhoidr*d2frhodrhodrho_col(atom2) + &
               drhojdr*drhojdr*d2frhodrhodrho_row(atom1)
               
#else

          d2 = d2vpdrdr + &
               d2rhoidrdr*dfrhodrho(atom2) + &
               d2rhojdrdr*dfrhodrho(atom1) + &
               drhoidr*drhoidr*d2frhodrhodrho(atom2) + &
               drhojdr*drhojdr*d2frhodrhodrho(atom1)
#endif
       end if


       if (do_stress) then
          
#ifdef IS_MPI
          id1 = tagRow(atom1)
          id2 = tagColumn(atom2)
#else
          id1 = atom1
          id2 = atom2
#endif
          
          if (molMembershipList(id1) .ne. molMembershipList(id2)) then

             tau_Temp(1) = tau_Temp(1) - d(1) * fx
             tau_Temp(2) = tau_Temp(2) - d(1) * fy
             tau_Temp(3) = tau_Temp(3) - d(1) * fz
             tau_Temp(4) = tau_Temp(4) - d(2) * fx
             tau_Temp(5) = tau_Temp(5) - d(2) * fy
             tau_Temp(6) = tau_Temp(6) - d(2) * fz
             tau_Temp(7) = tau_Temp(7) - d(3) * fx
             tau_Temp(8) = tau_Temp(8) - d(3) * fy
             tau_Temp(9) = tau_Temp(9) - d(3) * fz

             virial_Temp = virial_Temp + &
                  (tau_Temp(1) + tau_Temp(5) + tau_Temp(9))

          endif
       endif   
    endif

    
  end subroutine do_eam_pair


  subroutine eam_splint(nx, xa, ya, yppa, x, y, dy, d2y)

    integer :: atype, nx, j
    real( kind = DP ), dimension(:) :: xa
    real( kind = DP ), dimension(:) :: ya
    real( kind = DP ), dimension(:) :: yppa
    real( kind = DP ) :: x, y
    real( kind = DP ) :: dy, d2y
    real( kind = DP ) :: del, h, a, b, c, d
    integer :: pp_arraySize

 
    ! this spline code assumes that the x points are equally spaced
    ! do not attempt to use this code if they are not.
    
    
    ! find the closest point with a value below our own:
    j = FLOOR(real((nx-1),kind=dp) * (x - xa(1)) / (xa(nx) - xa(1))) + 1

    ! check to make sure we're inside the spline range:
    if ((j.gt.nx).or.(j.lt.1)) then
       write(errMSG,*) "EAM_splint: x is outside bounds of spline"
       call handleError(routineName,errMSG)
    endif
    ! check to make sure we haven't screwed up the calculation of j:
    if ((x.lt.xa(j)).or.(x.gt.xa(j+1))) then
       if (j.ne.nx) then
        write(errMSG,*) "EAM_splint:",x," x is outside bounding range"
       call handleError(routineName,errMSG)
       endif
    endif

    del = xa(j+1) - x
    h = xa(j+1) - xa(j)
    
    a = del / h
    b = 1.0E0_DP - a
    c = a*(a*a - 1.0E0_DP)*h*h/6.0E0_DP
    d = b*(b*b - 1.0E0_DP)*h*h/6.0E0_DP
    
    y = a*ya(j) + b*ya(j+1) + c*yppa(j) + d*yppa(j+1)
  
       dy = (ya(j+1)-ya(j))/h &
            - (3.0E0_DP*a*a - 1.0E0_DP)*h*yppa(j)/6.0E0_DP &
            + (3.0E0_DP*b*b - 1.0E0_DP)*h*yppa(j+1)/6.0E0_DP
  
  
       d2y = a*yppa(j) + b*yppa(j+1)
  

  end subroutine eam_splint


  subroutine eam_spline(nx, xa, ya, yppa, yp1, ypn, boundary)


    ! yp1 and ypn are the first derivatives of y at the two endpoints
    ! if boundary is 'L' the lower derivative is used
    ! if boundary is 'U' the upper derivative is used
    ! if boundary is 'B' then both derivatives are used
    ! if boundary is anything else, then both derivatives are assumed to be 0
    
    integer :: nx, i, k, max_array_size
    
    real( kind = DP ), dimension(:)        :: xa
    real( kind = DP ), dimension(:)        :: ya
    real( kind = DP ), dimension(:)        :: yppa
    real( kind = DP ), dimension(size(xa)) :: u
    real( kind = DP ) :: yp1,ypn,un,qn,sig,p
    character(len=*) :: boundary
    
    ! make sure the sizes match
    if ((nx /= size(xa)) .or. (nx /= size(ya))) then
       call handleWarning("EAM_SPLINE","Array size mismatch")
    end if

    if ((boundary.eq.'l').or.(boundary.eq.'L').or. &
         (boundary.eq.'b').or.(boundary.eq.'B')) then
       yppa(1) = -0.5E0_DP
       u(1) = (3.0E0_DP/(xa(2)-xa(1)))*((ya(2)-&
            ya(1))/(xa(2)-xa(1))-yp1)
    else
       yppa(1) = 0.0E0_DP
       u(1)  = 0.0E0_DP
    endif
    
    do i = 2, nx - 1
       sig = (xa(i) - xa(i-1)) / (xa(i+1) - xa(i-1))
       p = sig * yppa(i-1) + 2.0E0_DP
       yppa(i) = (sig - 1.0E0_DP) / p
       u(i) = (6.0E0_DP*((ya(i+1)-ya(i))/(xa(i+1)-xa(i)) - &
            (ya(i)-ya(i-1))/(xa(i)-xa(i-1)))/ &
            (xa(i+1)-xa(i-1)) - sig * u(i-1))/p
    enddo
    
    if ((boundary.eq.'u').or.(boundary.eq.'U').or. &
         (boundary.eq.'b').or.(boundary.eq.'B')) then
       qn = 0.5E0_DP
       un = (3.0E0_DP/(xa(nx)-xa(nx-1)))* &
            (ypn-(ya(nx)-ya(nx-1))/(xa(nx)-xa(nx-1)))
    else
       qn = 0.0E0_DP
       un = 0.0E0_DP
    endif

    yppa(nx)=(un-qn*u(nx-1))/(qn*yppa(nx-1)+1.0E0_DP)
    
    do k = nx-1, 1, -1
       yppa(k)=yppa(k)*yppa(k+1)+u(k)
    enddo

  end subroutine eam_spline


end module eam
Revision:	801
Committed:	Sat Oct 4 18:46:12 2003 UTC (20 years, 9 months ago) by chuckv
File size:	29488 byte(s)
Log Message:	Fixed bug in calc_eam.