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cc/*@@
c  @file      ADMConstraints.F
c  @date      Aug 98
c  @desc 
c     Calculate the ADM Constraints for output:
c    
c     Hamiltonian Constraint is:
c
c       R - K^i_j K^j_i + trK^2 - 16 Pi rho
c
c     Momentum Constraints are:
c
c       Del_j K_i^j - Del_i trK - 8 Pi j_i
c
c  @enddesc
c@@*/

#include "cctk.h"
#include "cctk_Parameters.h"
#include "cctk_Arguments.h"
 
#include "CactusEinstein/Einstein/src/Einstein.h"


      subroutine ADMConstraints(CCTK_ARGUMENTS)
      
      implicit none

      DECLARE_CCTK_ARGUMENTS
      DECLARE_CCTK_PARAMETERS
      DECLARE_CCTK_FUNCTIONS

      integer :: i,j,k
      integer :: nx,ny,nz

c     Stencil width used for calculating constraints
c     (for outer boundary condition)

      integer, dimension(3),parameter :: sw = 1

c     Return code from Cactus boundary conditions.

      integer ierr

c     Various real variables.

      CCTK_REAL :: dx,dy,dz
      CCTK_REAL :: m_rho,m_sx,m_sy,m_sz
      CCTK_REAL :: pi,ialp,ialp2

c     Temporaries for the Stress-Energy tensor.

      CCTK_REAL :: Ttt,Ttx,Tty,Ttz,Txx,Txy,Txz,Tyy,Tyz,Tzz

c     Matter declarations.

#include "CalcTmunu_temps.inc"

c     Macros from Standard Einstein.

#include "CactusEinstein/Einstein/src/macro/HAMADM_declare.h"
#include "CactusEinstein/Einstein/src/macro/MOMXADM_declare.h"
#include "CactusEinstein/Einstein/src/macro/MOMYADM_declare.h"
#include "CactusEinstein/Einstein/src/macro/MOMZADM_declare.h"


c --------------------------------------------------------------

c     Grid parameters.

      dx = cctk_delta_space(1)
      dy = cctk_delta_space(2)
      dz = cctk_delta_space(3)

      nx = cctk_lsh(1)
      ny = cctk_lsh(2)
      nz = cctk_lsh(3)

c     Fill with zeros.

      ham = 0.0D0

      momx = 0.0D0
      momy = 0.0D0
      momz = 0.0D0

c     Calculate constraints.

      pi = acos(-1.0D0)

      do k=2,nz-1
         do j=2,ny-1
            do i=2,nx-1

               ialp  = 1.0D0/alp(i,j,k)
               ialp2 = ialp**2

c              Calculate the stress energy tensor at this point
c              ------------------------------------------------

c              Initialize stress-energy tensor components.

               Ttt = 0.0D0

               Ttx = 0.0D0; Tty = 0.0D0; Ttz = 0.0D0

               Txx = 0.0D0; Tyy = 0.0D0; Tzz = 0.0D0
               Txy = 0.0D0; Txz = 0.0D0; Tyz = 0.0D0

c              Include macro for stress energy tensor.

#include "CalcTmunu.inc"

c              Calculate the hamiltonian constraint
c              ------------------------------------

c              Geometric piece.

#include "CactusEinstein/Einstein/src/macro/HAMADM_guts.h"

c              Add matter terms: - 16*pi*rho
c
c              with rho defined as:
c
c              rho = n_a n_b T^{ab} = n^a n^b T_{ab}
c                  = (T_00 - 2 beta^i T_{i0} + beta^i beta^j T_{ij})/alpha^2

               m_rho = ialp2*Ttt

               if (shift_state == SHIFT_ACTIVE) then

                  m_rho = m_rho + ialp2
     &               *(betax(i,j,k)**2*Txx
     &               + betay(i,j,k)**2*Tyy
     &               + betaz(i,j,k)**2*Tzz
     &               +(betax(i,j,k)*betay(i,j,k)*Txy
     &               + betax(i,j,k)*betaz(i,j,k)*Txz
     &               + betay(i,j,k)*betaz(i,j,k)*Tyz)*2.0D0
     &               -(betax(i,j,k)**2*Ttx
     &               + betay(i,j,k)**2*Tty
     &               + betaz(i,j,k)**2*Ttz)*2.0D0)

               end if

               ham(i,j,k) = HAMADM_HAMADM - 16.0D0*pi*m_rho


c              Calculate the Momentum constraints
c              ----------------------------------

c              Geometric piece.

#include "CactusEinstein/Einstein/src/macro/MOMXADM_guts.h"
#include "CactusEinstein/Einstein/src/macro/MOMYADM_guts.h"
#include "CactusEinstein/Einstein/src/macro/MOMZADM_guts.h"

c              Add matter terms: - 8*pi*S_i
c
c              with S_i defined as:
c
c              S_i = - g_{ia} n_b T^{ab} = - g_i^a n^b T_{ab} 
c                  = - (T_{i0} - beta^j T_{ij})/alpha

               m_sx = - ialp*Ttx
               m_sy = - ialp*Tty
               m_sz = - ialp*Ttz

               if (shift_state == SHIFT_ACTIVE) then

                  m_sx = m_sx + ialp
     &                 *(betax(i,j,k)*Txx
     &                 + betay(i,j,k)*Txy
     &                 + betaz(i,j,k)*Txz)

                  m_sy = m_sy + ialp
     &                 *(betax(i,j,k)*Txy
     &                 + betay(i,j,k)*Tyy
     &                 + betaz(i,j,k)*Tyz)

                  m_sz = m_sz + ialp
     &                 *(betax(i,j,k)*Txz
     &                 + betay(i,j,k)*Tyz
     &                 + betaz(i,j,k)*Tzz)

               end if

               momx(i,j,k) = MOMXADM_MOMXADM - 8.0D0*pi*m_sx
               momy(i,j,k) = MOMYADM_MOMYADM - 8.0D0*pi*m_sy
               momz(i,j,k) = MOMZADM_MOMZADM - 8.0D0*pi*m_sz

            end do
         end do 
      end do

#include "CactusEinstein/Einstein/src/macro/HAMADM_undefine.h"
#include "CactusEinstein/Einstein/src/macro/MOMXADM_undefine.h"
#include "CactusEinstein/Einstein/src/macro/MOMYADM_undefine.h"
#include "CactusEinstein/Einstein/src/macro/MOMZADM_undefine.h"

c     Apply symmetry boundary conditions.

      call CartSymGN(ierr,cctkGH,"admconstraints::admconstraints")

c     Apply flat boundary conditions at outer boundaries.

      if (CCTK_Equals(bound,"flat") == 1) then
         call BndFlatGN(ierr,cctkGH,sw,"admconstraints::admconstraints")
      end if

c     Synchronize.

      if (constraint_communication.eq.1) then
         call CCTK_SyncGroup(cctkGH,"admconstraints::admconstraints")
      end if

c     End

      end subroutine ADMConstraints