| 1 |
!! Calculates Long Range forces Lennard-Jones interactions. |
| 2 |
!! Corresponds to the force field defined in lj_FF.cpp |
| 3 |
!! @author Charles F. Vardeman II |
| 4 |
!! @author Matthew Meineke |
| 5 |
!! @version $Id: lj_FF.F90,v 1.12 2003-01-28 22:16:55 chuckv Exp $, $Date: 2003-01-28 22:16:55 $, $Name: not supported by cvs2svn $, $Revision: 1.12 $ |
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module lj_ff |
| 10 |
use simulation |
| 11 |
use definitions |
| 12 |
use generic_atypes |
| 13 |
#ifdef IS_MPI |
| 14 |
use mpiSimulation |
| 15 |
#endif |
| 16 |
implicit none |
| 17 |
PRIVATE |
| 18 |
|
| 19 |
!! Number of lj_atypes in lj_atype_list |
| 20 |
integer, save :: n_lj_atypes = 0 |
| 21 |
|
| 22 |
!! Global list of lj atypes in simulation |
| 23 |
type (lj_atype), pointer :: ljListHead => null() |
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type (lj_atype), pointer :: ljListTail => null() |
| 25 |
|
| 26 |
|
| 27 |
!! LJ mixing array |
| 28 |
type (lj_atype), dimension(:,:), pointer :: ljMixed => null() |
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|
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|
| 31 |
!! Neighbor list and commom arrays |
| 32 |
!! This should eventally get moved to a neighbor list type |
| 33 |
integer, allocatable, dimension(:) :: point |
| 34 |
integer, allocatable, dimension(:) :: list |
| 35 |
integer, parameter :: listMultiplier = 80 |
| 36 |
integer :: nListAllocs = 0 |
| 37 |
integer, parameter :: maxListAllocs = 5 |
| 38 |
|
| 39 |
|
| 40 |
!! Atype identity pointer lists |
| 41 |
#ifdef IS_MPI |
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!! Row lj_atype pointer list |
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type (lj_atypePtr), dimension(:), pointer :: identPtrListRow => null() |
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!! Column lj_atype pointer list |
| 45 |
type (lj_atypePtr), dimension(:), pointer :: identPtrListColumn => null() |
| 46 |
#else |
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type( lj_identPtrList ), dimension(:), pointer :: identPtrList => null() |
| 48 |
#endif |
| 49 |
|
| 50 |
|
| 51 |
!! Logical has lj force field module been initialized? |
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logical, save :: isljFFinit = .false. |
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|
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|
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!! Public methods and data |
| 56 |
public :: new_lj_atype |
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public :: do_lj_ff |
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public :: getLjPot |
| 59 |
public :: init_ljFF |
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|
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|
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|
| 63 |
|
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contains |
| 65 |
|
| 66 |
!! Adds a new lj_atype to the list. |
| 67 |
subroutine new_lj_atype(ident,mass,epsilon,sigma,status) |
| 68 |
real( kind = dp ), intent(in) :: mass |
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real( kind = dp ), intent(in) :: epsilon |
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real( kind = dp ), intent(in) :: sigma |
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integer, intent(in) :: ident |
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integer, intent(out) :: status |
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|
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type (lj_atype), pointer :: newLJ_atype |
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integer :: alloc_error |
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integer :: atype_counter = 0 |
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integer :: alloc_size |
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integer :: err_stat |
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status = 0 |
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|
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|
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|
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! allocate a new atype |
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allocate(newLJ_atype,stat=alloc_error) |
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if (alloc_error /= 0 ) then |
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status = -1 |
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return |
| 88 |
end if |
| 89 |
|
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! assign our new lj_atype information |
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newLJ_atype%mass = mass |
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newLJ_atype%epsilon = epsilon |
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newLJ_atype%sigma = sigma |
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newLJ_atype%sigma2 = sigma * sigma |
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newLJ_atype%sigma6 = newLJ_atype%sigma2 * newLJ_atype%sigma2 & |
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* newLJ_atype%sigma2 |
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! assume that this atype will be successfully added |
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newLJ_atype%atype_ident = ident |
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newLJ_atype%atype_number = n_lj_atypes + 1 |
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|
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call add_atype(newLJ_atype,ljListHead,ljListTail,err_stat) |
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if (err_stat /= 0 ) then |
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status = -1 |
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return |
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endif |
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|
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n_lj_atypes = n_lj_atypes + 1 |
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|
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|
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end subroutine new_lj_atype |
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|
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|
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subroutine init_ljFF(nComponents,ident, status) |
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!! Number of components in ident array |
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integer, intent(inout) :: nComponents |
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!! Array of identities nComponents long corresponding to |
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!! ljatype ident. |
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integer, dimension(nComponents),intent(inout) :: ident |
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!! Result status, success = 0, error = -1 |
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integer, intent(out) :: Status |
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|
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integer :: alloc_stat |
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|
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integer :: thisStat |
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integer :: i |
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#ifdef IS_MPI |
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integer, allocatable, dimension(:) :: identRow |
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integer, allocatable, dimension(:) :: identCol |
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integer :: nrow |
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integer :: ncol |
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integer :: alloc_stat |
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#endif |
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status = 0 |
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!! if were're not in MPI, we just update ljatypePtrList |
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#ifndef IS_MPI |
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call create_IdentPtrlst(ident,ljListHead,identPtrList,thisStat) |
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if ( thisStat /= 0 ) then |
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status = -1 |
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return |
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endif |
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|
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!! Allocate pointer lists |
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allocate(point(nComponents),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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|
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allocate(list(nComponents*listMultiplier),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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|
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! if were're in MPI, we also have to worry about row and col lists |
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#else |
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! We can only set up forces if mpiSimulation has been setup. |
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if (.not. isMPISimSet()) then |
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status = -1 |
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return |
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endif |
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nrow = getNrow() |
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ncol = getNcol() |
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!! Allocate temperary arrays to hold gather information |
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allocate(identRow(nrow),stat=alloc_stat) |
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if (alloc_stat /= 0 ) then |
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status = -1 |
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return |
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endif |
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|
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allocate(identCol(ncol),stat=alloc_stat) |
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if (alloc_stat /= 0 ) then |
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status = -1 |
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return |
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endif |
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!! Gather idents into row and column idents |
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call gather(ident,identRow,plan_row) |
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call gather(ident,identCol,plan_col) |
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|
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!! Create row and col pointer lists |
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call create_IdentPtrlst(identRow,ljListTail,identPtrListRow,thisStat) |
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if (thisStat /= 0 ) then |
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status = -1 |
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return |
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endif |
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|
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call create_IdentPtrlst(identCol,ljListTail,identPtrListCol,thisStat) |
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if (thisStat /= 0 ) then |
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status = -1 |
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return |
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endif |
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|
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!! free temporary ident arrays |
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deallocate(identCol) |
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deallocate(identRow) |
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|
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|
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!! Allocate neighbor lists for mpi simulations. |
| 199 |
if (.not. allocated(point)) then |
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allocate(point(nrow),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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|
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allocate(list(ncol*listMultiplier),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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else |
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deallocate(list) |
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deallocate(point) |
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allocate(point(nrow),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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|
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allocate(list(ncol*listMultiplier),stat=alloc_stat) |
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if (alloc_stat /=0) then |
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status = -1 |
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return |
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endif |
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endif |
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|
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#endif |
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|
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call createMixingList(thisStat) |
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if (thisStat /= 0) then |
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status = -1 |
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return |
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endif |
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isljFFinit = .true. |
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|
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end subroutine init_ljFF |
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|
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|
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|
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|
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|
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|
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subroutine createMixingList(status) |
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integer :: listSize |
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integer :: status |
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integer :: i |
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integer :: j |
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|
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integer :: outerCounter = 0 |
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integer :: innerCounter = 0 |
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type (lj_atype), pointer :: tmpPtrOuter => null() |
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type (lj_atype), pointer :: tmpPtrInner => null() |
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status = 0 |
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|
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listSize = getListLen(ljListHead) |
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if (listSize == 0) then |
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status = -1 |
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return |
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end if |
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|
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|
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if (.not. associated(ljMixed)) then |
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allocate(ljMixed(listSize,listSize)) |
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else |
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status = -1 |
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return |
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end if |
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|
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|
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|
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tmpPtrOuter => ljListHead |
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tmpPtrInner => tmpPtrOuter%next |
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do while (associated(tmpPtrOuter)) |
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outerCounter = outerCounter + 1 |
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! do self mixing rule |
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ljMixed(outerCounter,outerCounter)%sigma = tmpPtrOuter%sigma |
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|
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ljMixed(outerCounter,outerCounter)%sigma2 = ljMixed(outerCounter,outerCounter)%sigma & |
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* ljMixed(outerCounter,outerCounter)%sigma |
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|
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ljMixed(outerCounter,outerCounter)%sigma6 = ljMixed(outerCounter,outerCounter)%sigma2 & |
| 282 |
* ljMixed(outerCounter,outerCounter)%sigma2 & |
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* ljMixed(outerCounter,outerCounter)%sigma2 |
| 284 |
|
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ljMixed(outerCounter,outerCounter)%epsilon = tmpPtrOuter%epsilon |
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|
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innerCounter = outerCounter + 1 |
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do while (associated(tmpPtrInner)) |
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|
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ljMixed(outerCounter,innerCounter)%sigma = & |
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calcLJMix("sigma",tmpPtrOuter%sigma, & |
| 292 |
tmpPtrInner%sigma) |
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|
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ljMixed(outerCounter,innerCounter)%sigma2 = & |
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ljMixed(outerCounter,innerCounter)%sigma & |
| 296 |
* ljMixed(outerCounter,innerCounter)%sigma |
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|
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ljMixed(outerCounter,innerCounter)%sigma6 = & |
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ljMixed(outerCounter,innerCounter)%sigma2 & |
| 300 |
* ljMixed(outerCounter,innerCounter)%sigma2 & |
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* ljMixed(outerCounter,innerCounter)%sigma2 |
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|
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ljMixed(outerCounter,innerCounter)%epsilon = & |
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calcLJMix("epsilon",tmpPtrOuter%epsilon, & |
| 305 |
tmpPtrInner%epsilon) |
| 306 |
ljMixed(innerCounter,outerCounter)%sigma = ljMixed(outerCounter,innerCounter)%sigma |
| 307 |
ljMixed(innerCounter,outerCounter)%sigma2 = ljMixed(outerCounter,innerCounter)%sigma2 |
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ljMixed(innerCounter,outerCounter)%sigma6 = ljMixed(outerCounter,innerCounter)%sigma6 |
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ljMixed(innerCounter,outerCounter)%epsilon = ljMixed(outerCounter,innerCounter)%epsilon |
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|
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|
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tmpPtrInner => tmpPtrInner%next |
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innerCounter = innerCounter + 1 |
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end do |
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! advance pointers |
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tmpPtrOuter => tmpPtrOuter%next |
| 317 |
if (associated(tmpPtrOuter)) then |
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tmpPtrInner => tmpPtrOuter%next |
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endif |
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|
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end do |
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|
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end subroutine createMixingList |
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|
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|
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|
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|
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|
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|
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|
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|
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!! FORCE routine Calculates Lennard Jones forces. |
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!-------------------------------------------------------------> |
| 334 |
subroutine do_lj_ff(q,f,potE,do_pot) |
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!! Position array provided by C, dimensioned by getNlocal |
| 336 |
real ( kind = dp ), dimension(3,getNlocal()) :: q |
| 337 |
!! Force array provided by C, dimensioned by getNlocal |
| 338 |
real ( kind = dp ), dimension(3,getNlocal()) :: f |
| 339 |
real ( kind = dp ) :: potE |
| 340 |
logical ( kind = 2) :: do_pot |
| 341 |
|
| 342 |
type(lj_atype), pointer :: ljAtype_i |
| 343 |
type(lj_atype), pointer :: ljAtype_j |
| 344 |
|
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#ifdef MPI |
| 346 |
real( kind = DP ), dimension(3,getNcol()) :: efr |
| 347 |
real( kind = DP ) :: pot_local |
| 348 |
#else |
| 349 |
real( kind = DP ), dimension(3,getNlocal()) :: efr |
| 350 |
#endif |
| 351 |
|
| 352 |
!! Local arrays needed for MPI |
| 353 |
#ifdef IS_MPI |
| 354 |
real(kind = dp), dimension(3:getNrow()) :: qRow |
| 355 |
real(kind = dp), dimension(3:getNcol()) :: qCol |
| 356 |
|
| 357 |
real(kind = dp), dimension(3:getNrow()) :: fRow |
| 358 |
real(kind = dp), dimension(3:getNcol()) :: fCol |
| 359 |
|
| 360 |
real(kind = dp), dimension(getNrow()) :: eRow |
| 361 |
real(kind = dp), dimension(getNcol()) :: eCol |
| 362 |
|
| 363 |
real(kind = dp), dimension(getNlocal()) :: eTemp |
| 364 |
#endif |
| 365 |
|
| 366 |
|
| 367 |
|
| 368 |
real( kind = DP ) :: pe |
| 369 |
logical :: update_nlist |
| 370 |
|
| 371 |
|
| 372 |
integer :: i, j, jbeg, jend, jnab, idim, jdim, idim2, jdim2, dim, dim2 |
| 373 |
integer :: nlist |
| 374 |
integer :: j_start |
| 375 |
integer :: tag_i,tag_j |
| 376 |
real( kind = DP ) :: r, pot, ftmp, dudr, d2, drdx1, kt1, kt2, kt3, ktmp |
| 377 |
real( kind = DP ) :: rxi, ryi, rzi, rxij, ryij, rzij, rijsq |
| 378 |
real( kind = DP ) :: rlistsq, rcutsq,rlist,rcut |
| 379 |
|
| 380 |
! a rig that need to be fixed. |
| 381 |
#ifdef IS_MPI |
| 382 |
logical :: newtons_thrd = .true. |
| 383 |
real( kind = dp ) :: pe_local |
| 384 |
integer :: nlocal |
| 385 |
#endif |
| 386 |
integer :: nrow |
| 387 |
integer :: ncol |
| 388 |
integer :: natoms |
| 389 |
|
| 390 |
! Make sure we are properly initialized. |
| 391 |
if (.not. isljFFInit) then |
| 392 |
write(default_error,*) "ERROR: lj_FF has not been properly initialized" |
| 393 |
return |
| 394 |
endif |
| 395 |
#ifdef IS_MPI |
| 396 |
if (.not. isMPISimSet()) then |
| 397 |
write(default_error,*) "ERROR: mpiSimulation has not been properly initialized" |
| 398 |
return |
| 399 |
endif |
| 400 |
#endif |
| 401 |
|
| 402 |
!! initialize local variables |
| 403 |
natoms = getNlocal() |
| 404 |
call getRcut(rcut,rcut2=rcutsq) |
| 405 |
call getRlist(rlist,rlistsq) |
| 406 |
#ifndef IS_MPI |
| 407 |
nrow = natoms - 1 |
| 408 |
ncol = natoms |
| 409 |
#else |
| 410 |
nrow = getNrow(plan_row) |
| 411 |
ncol = getNcol(plan_col) |
| 412 |
nlocal = natoms |
| 413 |
j_start = 1 |
| 414 |
#endif |
| 415 |
|
| 416 |
|
| 417 |
!! See if we need to update neighbor lists |
| 418 |
call check(q,update_nlist) |
| 419 |
|
| 420 |
!--------------WARNING........................... |
| 421 |
! Zero variables, NOTE:::: Forces are zeroed in C |
| 422 |
! Zeroing them here could delete previously computed |
| 423 |
! Forces. |
| 424 |
!------------------------------------------------ |
| 425 |
#ifndef IS_MPI |
| 426 |
! nloops = nloops + 1 |
| 427 |
pe = 0.0E0_DP |
| 428 |
|
| 429 |
#else |
| 430 |
f_row = 0.0E0_DP |
| 431 |
f_col = 0.0E0_DP |
| 432 |
|
| 433 |
pe_local = 0.0E0_DP |
| 434 |
|
| 435 |
eRow = 0.0E0_DP |
| 436 |
eCol = 0.0E0_DP |
| 437 |
eTemp = 0.0E0_DP |
| 438 |
#endif |
| 439 |
efr = 0.0E0_DP |
| 440 |
|
| 441 |
! communicate MPI positions |
| 442 |
#ifdef MPI |
| 443 |
call gather(q,qRow,plan_row3) |
| 444 |
call gather(q,qCol,plan_col3) |
| 445 |
#endif |
| 446 |
|
| 447 |
|
| 448 |
if (update_nlist) then |
| 449 |
|
| 450 |
! save current configuration, contruct neighbor list, |
| 451 |
! and calculate forces |
| 452 |
call save_nlist(q) |
| 453 |
|
| 454 |
nlist = 0 |
| 455 |
|
| 456 |
|
| 457 |
|
| 458 |
do i = 1, nrow |
| 459 |
point(i) = nlist + 1 |
| 460 |
#ifdef MPI |
| 461 |
ljAtype_i => identPtrListRow(i)%this |
| 462 |
tag_i = tagRow(i) |
| 463 |
rxi = qRow(1,i) |
| 464 |
ryi = qRow(2,i) |
| 465 |
rzi = qRow(3,i) |
| 466 |
#else |
| 467 |
ljAtype_i => identPtrList(i)%this |
| 468 |
j_start = i + 1 |
| 469 |
rxi = q(1,i) |
| 470 |
ryi = q(2,i) |
| 471 |
rzi = q(3,i) |
| 472 |
#endif |
| 473 |
|
| 474 |
inner: do j = j_start, ncol |
| 475 |
#ifdef MPI |
| 476 |
! Assign identity pointers and tags |
| 477 |
ljAtype_j => identPtrListColumn(j)%this |
| 478 |
tag_j = tagCol(j) |
| 479 |
if (newtons_thrd) then |
| 480 |
if (tag_i <= tag_j) then |
| 481 |
if (mod(tag_i + tag_j,2) == 0) cycle inner |
| 482 |
else |
| 483 |
if (mod(tag_i + tag_j,2) == 1) cycle inner |
| 484 |
endif |
| 485 |
endif |
| 486 |
|
| 487 |
rxij = wrap(rxi - qCol(1,j), 1) |
| 488 |
ryij = wrap(ryi - qCol(2,j), 2) |
| 489 |
rzij = wrap(rzi - qCol(3,j), 3) |
| 490 |
#else |
| 491 |
ljAtype_j => identPtrList(j)%this |
| 492 |
rxij = wrap(rxi - q(1,j), 1) |
| 493 |
ryij = wrap(ryi - q(2,j), 2) |
| 494 |
rzij = wrap(rzi - q(3,j), 3) |
| 495 |
|
| 496 |
#endif |
| 497 |
rijsq = rxij*rxij + ryij*ryij + rzij*rzij |
| 498 |
|
| 499 |
#ifdef MPI |
| 500 |
if (rijsq <= rlistsq .AND. & |
| 501 |
tag_j /= tag_i) then |
| 502 |
#else |
| 503 |
if (rijsq < rlistsq) then |
| 504 |
#endif |
| 505 |
|
| 506 |
nlist = nlist + 1 |
| 507 |
if (nlist > size(list)) then |
| 508 |
!! "Change how nlist size is done" |
| 509 |
write(DEFAULT_ERROR,*) "ERROR: nlist > list size" |
| 510 |
endif |
| 511 |
list(nlist) = j |
| 512 |
|
| 513 |
|
| 514 |
if (rijsq < rcutsq) then |
| 515 |
|
| 516 |
r = dsqrt(rijsq) |
| 517 |
|
| 518 |
call getLJPot(r,pot,dudr,ljAtype_i,ljAtype_j) |
| 519 |
|
| 520 |
#ifdef MPI |
| 521 |
eRow(i) = eRow(i) + pot*0.5 |
| 522 |
eCol(i) = eCol(i) + pot*0.5 |
| 523 |
#else |
| 524 |
pe = pe + pot |
| 525 |
#endif |
| 526 |
|
| 527 |
efr(1,j) = -rxij |
| 528 |
efr(2,j) = -ryij |
| 529 |
efr(3,j) = -rzij |
| 530 |
|
| 531 |
do dim = 1, 3 |
| 532 |
|
| 533 |
|
| 534 |
drdx1 = efr(dim,j) / r |
| 535 |
ftmp = dudr * drdx1 |
| 536 |
|
| 537 |
|
| 538 |
#ifdef MPI |
| 539 |
fCol(dim,j) = fCol(dim,j) - ftmp |
| 540 |
fRow(dim,i) = fRow(dim,i) + ftmp |
| 541 |
#else |
| 542 |
|
| 543 |
f(dim,j) = f(dim,j) - ftmp |
| 544 |
f(dim,i) = f(dim,i) + ftmp |
| 545 |
|
| 546 |
#endif |
| 547 |
enddo |
| 548 |
endif |
| 549 |
endif |
| 550 |
enddo inner |
| 551 |
enddo |
| 552 |
|
| 553 |
#ifdef MPI |
| 554 |
point(nrow + 1) = nlist + 1 |
| 555 |
#else |
| 556 |
point(natoms) = nlist + 1 |
| 557 |
#endif |
| 558 |
|
| 559 |
else |
| 560 |
|
| 561 |
! use the list to find the neighbors |
| 562 |
do i = 1, nrow |
| 563 |
JBEG = POINT(i) |
| 564 |
JEND = POINT(i+1) - 1 |
| 565 |
! check thiat molecule i has neighbors |
| 566 |
if (jbeg .le. jend) then |
| 567 |
#ifdef MPI |
| 568 |
ljAtype_i => identPtrListRow(i)%this |
| 569 |
rxi = qRow(1,i) |
| 570 |
ryi = qRow(2,i) |
| 571 |
rzi = qRow(3,i) |
| 572 |
#else |
| 573 |
ljAtype_i => identPtrList(i)%this |
| 574 |
rxi = q(1,i) |
| 575 |
ryi = q(2,i) |
| 576 |
rzi = q(3,i) |
| 577 |
#endif |
| 578 |
do jnab = jbeg, jend |
| 579 |
j = list(jnab) |
| 580 |
#ifdef MPI |
| 581 |
ljAtype_j = identPtrListColumn(j)%this |
| 582 |
rxij = wrap(rxi - q_col(1,j), 1) |
| 583 |
ryij = wrap(ryi - q_col(2,j), 2) |
| 584 |
rzij = wrap(rzi - q_col(3,j), 3) |
| 585 |
#else |
| 586 |
ljAtype_j = identPtrList(j)%this |
| 587 |
rxij = wrap(rxi - q(1,j), 1) |
| 588 |
ryij = wrap(ryi - q(2,j), 2) |
| 589 |
rzij = wrap(rzi - q(3,j), 3) |
| 590 |
#endif |
| 591 |
rijsq = rxij*rxij + ryij*ryij + rzij*rzij |
| 592 |
|
| 593 |
if (rijsq < rcutsq) then |
| 594 |
|
| 595 |
r = dsqrt(rijsq) |
| 596 |
|
| 597 |
call getLJPot(r,pot,dudr,ljAtype_i,ljAtype_j) |
| 598 |
#ifdef MPI |
| 599 |
eRow(i) = eRow(i) + pot*0.5 |
| 600 |
eCol(i) = eCol(i) + pot*0.5 |
| 601 |
#else |
| 602 |
pe = pe + pot |
| 603 |
#endif |
| 604 |
|
| 605 |
|
| 606 |
efr(1,j) = -rxij |
| 607 |
efr(2,j) = -ryij |
| 608 |
efr(3,j) = -rzij |
| 609 |
|
| 610 |
do dim = 1, 3 |
| 611 |
|
| 612 |
drdx1 = efr(dim,j) / r |
| 613 |
ftmp = dudr * drdx1 |
| 614 |
#ifdef MPI |
| 615 |
fCol(dim,j) = fCol(dim,j) - ftmp |
| 616 |
fRow(dim,i) = fRow(dim,i) + ftmp |
| 617 |
#else |
| 618 |
f(dim,j) = f(dim,j) - ftmp |
| 619 |
f(dim,i) = f(dim,i) + ftmp |
| 620 |
#endif |
| 621 |
enddo |
| 622 |
endif |
| 623 |
enddo |
| 624 |
endif |
| 625 |
enddo |
| 626 |
endif |
| 627 |
|
| 628 |
|
| 629 |
|
| 630 |
#ifdef MPI |
| 631 |
!!distribute forces |
| 632 |
call scatter(fRow,f,plan_row3) |
| 633 |
|
| 634 |
call scatter(fCol,f_tmp,plan_col3) |
| 635 |
|
| 636 |
do i = 1,nlocal |
| 637 |
f(1:3,i) = f(1:3,i) + f_tmp(1:3,i) |
| 638 |
end do |
| 639 |
|
| 640 |
|
| 641 |
|
| 642 |
if (do_pot) then |
| 643 |
! scatter/gather pot_row into the members of my column |
| 644 |
call scatter(e_row,e_tmp,plan_row) |
| 645 |
|
| 646 |
! scatter/gather pot_local into all other procs |
| 647 |
! add resultant to get total pot |
| 648 |
do i = 1, nlocal |
| 649 |
pe_local = pe_local + e_tmp(i) |
| 650 |
enddo |
| 651 |
if (newtons_thrd) then |
| 652 |
e_tmp = 0.0E0_DP |
| 653 |
call scatter(e_col,e_tmp,plan_col) |
| 654 |
do i = 1, nlocal |
| 655 |
pe_local = pe_local + e_tmp(i) |
| 656 |
enddo |
| 657 |
endif |
| 658 |
endif |
| 659 |
potE = pe_local |
| 660 |
#endif |
| 661 |
|
| 662 |
potE = pe |
| 663 |
|
| 664 |
|
| 665 |
end subroutine do_lj_ff |
| 666 |
|
| 667 |
!! Calculates the potential between two lj particles based on two lj_atype pointers, optionally returns second |
| 668 |
!! derivatives. |
| 669 |
subroutine getLjPot(r,pot,dudr,atype1,atype2,d2,status) |
| 670 |
! arguments |
| 671 |
!! Length of vector between particles |
| 672 |
real( kind = dp ), intent(in) :: r |
| 673 |
!! Potential Energy |
| 674 |
real( kind = dp ), intent(out) :: pot |
| 675 |
!! Derivatve wrt postion |
| 676 |
real( kind = dp ), intent(out) :: dudr |
| 677 |
!! Second Derivative, optional, used mainly for normal mode calculations. |
| 678 |
real( kind = dp ), intent(out), optional :: d2 |
| 679 |
|
| 680 |
type (lj_atype), pointer :: atype1 |
| 681 |
type (lj_atype), pointer :: atype2 |
| 682 |
|
| 683 |
integer, intent(out), optional :: status |
| 684 |
|
| 685 |
! local Variables |
| 686 |
real( kind = dp ) :: sigma |
| 687 |
real( kind = dp ) :: sigma2 |
| 688 |
real( kind = dp ) :: sigma6 |
| 689 |
real( kind = dp ) :: epsilon |
| 690 |
|
| 691 |
real( kind = dp ) :: rcut |
| 692 |
real( kind = dp ) :: rcut2 |
| 693 |
real( kind = dp ) :: rcut6 |
| 694 |
real( kind = dp ) :: r2 |
| 695 |
real( kind = dp ) :: r6 |
| 696 |
|
| 697 |
real( kind = dp ) :: t6 |
| 698 |
real( kind = dp ) :: t12 |
| 699 |
real( kind = dp ) :: tp6 |
| 700 |
real( kind = dp ) :: tp12 |
| 701 |
real( kind = dp ) :: delta |
| 702 |
|
| 703 |
logical :: doSec = .false. |
| 704 |
|
| 705 |
integer :: errorStat |
| 706 |
|
| 707 |
!! Optional Argument Checking |
| 708 |
! Check to see if we need to do second derivatives |
| 709 |
|
| 710 |
if (present(d2)) doSec = .true. |
| 711 |
if (present(status)) status = 0 |
| 712 |
|
| 713 |
! Look up the correct parameters in the mixing matrix |
| 714 |
sigma = ljMixed(atype1%atype_ident,atype2%atype_ident)%sigma |
| 715 |
sigma2 = ljMixed(atype1%atype_ident,atype2%atype_ident)%sigma2 |
| 716 |
sigma6 = ljMixed(atype1%atype_ident,atype2%atype_ident)%sigma6 |
| 717 |
epsilon = ljMixed(atype1%atype_ident,atype2%atype_ident)%epsilon |
| 718 |
|
| 719 |
|
| 720 |
|
| 721 |
call getRcut(rcut,rcut2=rcut2,rcut6=rcut6,status=errorStat) |
| 722 |
|
| 723 |
r2 = r * r |
| 724 |
r6 = r2 * r2 * r2 |
| 725 |
|
| 726 |
t6 = sigma6/ r6 |
| 727 |
t12 = t6 * t6 |
| 728 |
|
| 729 |
|
| 730 |
|
| 731 |
tp6 = sigma6 / rcut6 |
| 732 |
tp12 = tp6*tp6 |
| 733 |
|
| 734 |
delta = -4.0E0_DP*epsilon * (tp12 - tp6) |
| 735 |
|
| 736 |
if (r.le.rcut) then |
| 737 |
pot = 4.0E0_DP * epsilon * (t12 - t6) + delta |
| 738 |
dudr = 24.0E0_DP * epsilon * (t6 - 2.0E0_DP*t12) / r |
| 739 |
if(doSec) d2 = 24.0E0_DP * epsilon * (26.0E0_DP*t12 - 7.0E0_DP*t6)/r/r |
| 740 |
else |
| 741 |
pot = 0.0E0_DP |
| 742 |
dudr = 0.0E0_DP |
| 743 |
if(doSec) d2 = 0.0E0_DP |
| 744 |
endif |
| 745 |
|
| 746 |
return |
| 747 |
|
| 748 |
|
| 749 |
|
| 750 |
end subroutine getLjPot |
| 751 |
|
| 752 |
|
| 753 |
!! Calculates the mixing for sigma or epslon based on character string for initialzition of mixing array. |
| 754 |
function calcLJMix(thisParam,param1,param2,status) result(myMixParam) |
| 755 |
character(len=*) :: thisParam |
| 756 |
real(kind = dp) :: param1 |
| 757 |
real(kind = dp) :: param2 |
| 758 |
real(kind = dp ) :: myMixParam |
| 759 |
integer, optional :: status |
| 760 |
|
| 761 |
|
| 762 |
myMixParam = 0.0_dp |
| 763 |
|
| 764 |
if (present(status)) status = 0 |
| 765 |
|
| 766 |
select case (thisParam) |
| 767 |
|
| 768 |
case ("sigma") |
| 769 |
myMixParam = 0.5_dp * (param1 + param2) |
| 770 |
case ("epsilon") |
| 771 |
myMixParam = sqrt(param1 * param2) |
| 772 |
case default |
| 773 |
status = -1 |
| 774 |
end select |
| 775 |
|
| 776 |
end function calcLJMix |
| 777 |
|
| 778 |
|
| 779 |
|
| 780 |
end module lj_ff |
