!WRF:MODEL_LAYER:PHYSICS

!==============================================================================
!
! © 2009. Lawrence Livermore National Security, LLC. All rights reserved.
! This work was produced at the Lawrence Livermore National Laboratory (LLNL) under
! contract no. DE-AC52-07NA27344 (Contract 44) between the U.S. Department of Energy (DOE)
! and Lawrence Livermore National Security, LLC (LLNS) for the operation of LLNL. Copyright
! is reserved to Lawrence Livermore National Security, LLC for purposes of controlled
! dissemination, commercialization through formal licensing, or other disposition under
! terms of Contract 44; DOE policies, regulations and orders; and U.S. statutes. The rights
! of the Federal Government are reserved under Contract 44.
!
! DISCLAIMER
! This work was prepared as an account of work sponsored by an agency of the United States
! Government. Neither the United States Government nor Lawrence Livermore National
! Security, LLC nor any of their employees, makes any warranty, express or implied, or
! assumes any liability or responsibility for the accuracy, completeness, or usefulness of
! any information, apparatus, product, or process disclosed, or represents that its use
! would not infringe privately-owned rights. Reference herein to any specific commercial
! products, process, or service by trade name, trademark, manufacturer or otherwise does
! not necessarily constitute or imply its endorsement, recommendation, or favoring by the
! United States Government or Lawrence Livermore National Security, LLC. The views and
! opinions of authors expressed herein do not necessarily state or reflect those of the
! United States Government or Lawrence Livermore National Security, LLC, and shall not be
! used for advertising or product endorsement purposes.
!
! LICENSING REQUIREMENTS
! Any use, reproduction, modification, or distribution of this software or documentation
! for commercial purposes requires a license from Lawrence Livermore National Security,
! LLC. Contact: Lawrence Livermore National Laboratory, Industrial Partnerships Office,
! P.O. Box 808, L-795, Livermore, CA 94551
!
!=============================================================================
!
! Modification History: 
!
! Implemented 12/2009 by Jeff Mirocha, jmirocha@llnl.gov
!
!=============================================================================

MODULE module_sfs_nba

  USE module_configure, ONLY : grid_config_rec_type

  IMPLICIT NONE

  REAL :: c1, c2, c3, ce, cb, cs ! global model parameters           

CONTAINS

!=============================================================================

SUBROUTINE calc_mij_constants( )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute constants for Mij calculations 
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL :: sk, pi ! local model parameters           

!-----------------------------------------------------------------------------

  sk = 0.5
  pi = 3.1415927
  cb = 0.36

  cs = ( ( 8.0*( 1.0+cb ) )/( 27.0*pi**2 ) )**0.5
  c1 = ( ( 960.0**0.5 )*cb )/( 7.0*( 1.0+cb )*sk )
  c2 = c1
  ce = ( ( 8.0*pi/27.0 )**( 1.0/3.0 ) )*cs**( 4.0/3.0 )
  c3 = ( ( 27.0/( 8.0*pi ) )**( 1.0/3.0 ) )*cs**( 2.0/3.0 )

  RETURN

END SUBROUTINE calc_mij_constants

!=============================================================================

SUBROUTINE calc_smnsmn( smnsmn,                       &                
                        s11, s22, s33,                &
                        s12, s13, s23,                &
                        config_flags,                 &
                        ids, ide, jds, jde, kds, kde, &
                        ims, ime, jms, jme, kms, kme, &
                        ips, ipe, jps, jpe, kps, kpe, &
                        its, ite, jts, jte, kts, kte  )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute Smn*Smn = S11^2 + S22^2 + S33^2 + 2*(S12^2 + S13^2 +S23^2) 
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( OUT ) &
  :: smnsmn        ! Smn*Smn                             (s-2)
 
  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( IN  ) &
  :: s11         & ! 2*deformation element 11            (s-1)
   , s22         & ! 2*deformation element 22            (s-1)
   , s33         & ! 2*deformation element 33            (s-1)
   , s12         & ! 2*deformation element 12            (s-1)
   , s13         & ! 2*deformation element 13            (s-1)
   , s23           ! 2*deformation element 23            (s-1)

  TYPE (grid_config_rec_type),                           INTENT( IN  ) &
  :: config_flags

  INTEGER,                                               INTENT( IN  ) &
  :: ids, ide, jds, jde, kds, kde, &
     ims, ime, jms, jme, kms, kme, &
     ips, ipe, jps, jpe, kps, kpe, &
     its, ite, jts, jte, kts, kte

! LOCAL VARIABLES ------------------------------------------------------------
             
  REAL :: tmp

  INTEGER :: i, j, k, i_start, i_end, j_start, j_end, ktf

!-----------------------------------------------------------------------------
!
! Set loop limits,
! taken from /dyn_em/module_diffusion_em.F SUBROUTINE smag_km   
!
!-----------------------------------------------------------------------------
   
  ktf = min(kte,kde-1)

  i_start = its
  i_end   = MIN(ite,ide-1)
  j_start = jts
  j_end   = MIN(jte,jde-1)

  IF ( config_flags%open_xs .or. config_flags%specified .or. &
       config_flags%nested) i_start = MAX(ids+1,its)
  IF ( config_flags%open_xe .or. config_flags%specified .or. &
       config_flags%nested) i_end   = MIN(ide-2,ite)
  IF ( config_flags%open_ys .or. config_flags%specified .or. &
       config_flags%nested) j_start = MAX(jds+1,jts)
  IF ( config_flags%open_ye .or. config_flags%specified .or. &
       config_flags%nested) j_end   = MIN(jde-2,jte)
  IF ( config_flags%periodic_x ) i_start = its
  IF ( config_flags%periodic_x ) i_end = MIN( ite, ide-1 )

!-----------------------------------------------------------------------------

! Below the 0.25 factor divides the incoming WRF deformations, 
! which are multiplied by a factor of 2, by 2

  DO j=j_start,j_end
  DO k=kts,ktf
  DO i=i_start,i_end

    smnsmn(i,k,j) = 0.25*( s11(i,k,j)*s11(i,k,j) + &
                           s22(i,k,j)*s22(i,k,j) + &
                           s33(i,k,j)*s33(i,k,j) )

  END DO
  END DO
  END DO

! Below the 0.125 factor accounts for the four-point averaging (0.25)
! and divides the incoming WRF deformation elements by 2 (0.5) 

  DO j=j_start,j_end
  DO k=kts,ktf
  DO i=i_start,i_end

    tmp = 0.125*( s12(i  ,k,j) + s12(i  ,k,j+1) + &
                  s12(i+1,k,j) + s12(i+1,k,j+1) )
    smnsmn(i,k,j) = smnsmn(i,k,j) + 2.0*tmp*tmp

  END DO
  END DO
  END DO

  DO j=j_start,j_end
  DO k=kts,ktf
  DO i=i_start,i_end

    tmp = 0.125*( s13(i  ,k+1,j) + s13(i  ,k,j) + &
                  s13(i+1,k+1,j) + s13(i+1,k,j) )
    smnsmn(i,k,j) = smnsmn(i,k,j) + 2.0*tmp*tmp

  END DO
  END DO
  END DO

  DO j=j_start,j_end
  DO k=kts,ktf
  DO i=i_start,i_end

    tmp = 0.125*( s23(i,k+1,j  ) + s23(i,k,j  ) + &
                  s23(i,k+1,j+1) + s23(i,k,j+1) )
    smnsmn(i,k,j) = smnsmn(i,k,j) + 2.0*tmp*tmp
  
  END DO
  END DO
  END DO

  RETURN

END SUBROUTINE calc_smnsmn

!=============================================================================

SUBROUTINE calc_mii( m11, m22, m33,                &
                     s11, s22, s33,                &
                     s12, s13, s23,                &
                     r12, r13, r23, smnsmn,        &
                     tke, rdzw, dx, dy,            &
                     config_flags,                 &
                     ids, ide, jds, jde, kds, kde, &
                     ims, ime, jms, jme, kms, kme, &
                     ips, ipe, jps, jpe, kps, kpe, &
                     its, ite, jts, jte, kts, kte  )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute Mij for i = j
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( OUT ) &
  :: m11         & ! NBA stress element 11               (m2 s-2)
   , m22         & ! NBA stress element 22               (m2 s-2)
   , m33           ! NBA stress element 33               (m2 s-2)

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( IN  ) &
  :: s11         & ! 2*deformation element 11            (s-1)
   , s22         & ! 2*deformation element 22            (s-1)
   , s33         & ! 2*deformation element 33            (s-1)
   , s12         & ! 2*deformation element 12            (s-1)
   , s13         & ! 2*deformation element 13            (s-1)
   , s23         & ! 2*deformation element 23            (s-1)
   , r12         & ! 2*rotation element 12               (s-1)
   , r13         & ! 2*rotation element 13               (s-1)
   , r23         & ! 2*rotation element 23               (s-1)
   , smnsmn      & ! Smn*Smn                             (s-2)
   , tke         & ! tke                                 (m2 s-2)
   , rdzw          ! 1/dz at w-levels                    (m-1)

  REAL,                                                  INTENT( IN  ) &
  :: dx          & ! grid spacing in x                   (m)
   , dy            ! grid spacing in y                   (m) 

  TYPE (grid_config_rec_type),                           INTENT( IN  ) &
  :: config_flags

  INTEGER,                                               INTENT( IN  ) &
  :: ids, ide, jds, jde, kds, kde, &
     ims, ime, jms, jme, kms, kme, &
     ips, ipe, jps, jpe, kps, kpe, &
     its, ite, jts, jte, kts, kte

! LOCAL VARIABLES ------------------------------------------------------------

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! sij/2, rij/2
  :: ss11        & 
   , ss22        & 
   , ss33        & 
   , ss12        & 
   , ss13        & 
   , ss23        &          
   , rr12        & 
   , rr13        & 
   , rr23  

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! projected to c
  :: ss12c       & 
   , rr12c       & 
   , ss13c       & 
   , rr13c       & 
   , ss23c       & 
   , rr23c    

  REAL :: delta, a, b

  INTEGER :: i, j, k, i_start, i_end, j_start, j_end, ktf, is_ext, js_ext

!-----------------------------------------------------------------------------
!
! Set loop limits,
! taken from /dyn_em/module_diffusion_em.F SUBROUTINE cal_titau_11_22_33
!
!-----------------------------------------------------------------------------

  ktf = MIN( kte, kde-1 )

  i_start = its
  i_end   = ite
  j_start = jts
  j_end   = jte

    IF ( config_flags%open_xs .OR. config_flags%specified .OR. &
         config_flags%nested) i_start = MAX( ids+1, its )
    IF ( config_flags%open_xe .OR. config_flags%specified .OR. &
         config_flags%nested) i_end   = MIN( ide-1, ite )
    IF ( config_flags%open_ys .OR. config_flags%specified .OR. &
         config_flags%nested) j_start = MAX( jds+1, jts )
    IF ( config_flags%open_ye .OR. config_flags%specified .OR. &
         config_flags%nested) j_end   = MIN( jde-1, jte )
      IF ( config_flags%periodic_x ) i_start = its
      IF ( config_flags%periodic_x ) i_end = ite

  is_ext = 1
  js_ext = 1

  i_start = i_start - is_ext  
  j_start = j_start - js_ext   

!-----------------------------------------------------------------------------
!
! Divide WRF deformations, which are multiplied by 2, by 2
!
!-----------------------------------------------------------------------------

  DO j=j_start,j_end+1
  DO k=kts,ktf
  DO i=i_start,i_end+1

    ss11(i,k,j)=s11(i,k,j)/2.0
    ss22(i,k,j)=s22(i,k,j)/2.0
    ss33(i,k,j)=s33(i,k,j)/2.0
    ss12(i,k,j)=s12(i,k,j)/2.0
    ss13(i,k,j)=s13(i,k,j)/2.0
    ss23(i,k,j)=s23(i,k,j)/2.0
    rr12(i,k,j)=r12(i,k,j)/2.0
    rr13(i,k,j)=r13(i,k,j)/2.0
    rr23(i,k,j)=r23(i,k,j)/2.0

  END DO
  END DO
  END DO

  DO j=j_start,j_end+1
  DO i=i_start,i_end+1

    ss13(i,kde,j) = 0.0
    ss23(i,kde,j) = 0.0
    rr13(i,kde,j) = 0.0
    rr23(i,kde,j) = 0.0

  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Project variables to c
!
!-----------------------------------------------------------------------------

  DO j = j_start, j_end
  DO k = kts, ktf
  DO i = i_start, i_end

    ss12c(i,k,j) = 0.25*( ss12(i  ,k  ,j  ) + ss12(i  ,k  ,j+1) + &
                          ss12(i+1,k  ,j  ) + ss12(i+1,k  ,j+1) )

    rr12c(i,k,j) = 0.25*( rr12(i  ,k  ,j  ) + rr12(i  ,k  ,j+1) + &
                          rr12(i+1,k  ,j  ) + rr12(i+1,k  ,j+1) )

    ss13c(i,k,j) = 0.25*( ss13(i  ,k+1,j  ) + ss13(i  ,k  ,j  ) + &
                          ss13(i+1,k+1,j  ) + ss13(i+1,k  ,j  ) )

    rr13c(i,k,j) = 0.25*( rr13(i  ,k+1,j  ) + rr13(i  ,k  ,j  ) + &
                          rr13(i+1,k+1,j  ) + rr13(i+1,k  ,j  ) )

    ss23c(i,k,j) = 0.25*( ss23(i  ,k+1,j  ) + ss23(i  ,k  ,j  ) + &
                          ss23(i  ,k+1,j+1) + ss23(i  ,k  ,j+1) )

    rr23c(i,k,j) = 0.25*( rr23(i  ,k+1,j  ) + rr23(i  ,k  ,j  ) + &
                          rr23(i  ,k+1,j+1) + rr23(i  ,k  ,j+1) )

  ENDDO
  ENDDO
  ENDDO

!-----------------------------------------------------------------------------
!
! Calculate M11, M22 and M33
!
!-----------------------------------------------------------------------------

  IF ( config_flags%sfs_opt .EQ. 1 ) THEN !Do not use TKE

    DO j=j_start,j_end
    DO k=kts,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*( cs*delta )**2

      m11(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmn(i,k,j) )*ss11(i,k,j) &
                       + c1*(   ss11(i,k,j) *ss11(i,k,j)           &
                              + ss12c(i,k,j)*ss12c(i,k,j)          &
                              + ss13c(i,k,j)*ss13c(i,k,j)          &
                              - smnsmn(i,k,j)/3.0                  &
                            )                                      &
                       + c2*( -2.0*(   ss12c(i,k,j)*rr12c(i,k,j)   &
                                     + ss13c(i,k,j)*rr13c(i,k,j)   &
                                   )                               &
                            )                                      &
                     )

      m22(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmn(i,k,j) )*ss22(i,k,j) &
                       + c1*(   ss22(i,k,j) *ss22(i,k,j)           &
                              + ss12c(i,k,j)*ss12c(i,k,j)          &
                              + ss23c(i,k,j)*ss23c(i,k,j)          &
                              - smnsmn(i,k,j)/3.0                  &
                            )                                      &
                       + c2*(  2.0*(   ss12c(i,k,j)*rr12c(i,k,j)   &
                                     - ss23c(i,k,j)*rr23c(i,k,j)   &
                                   )                               &
                            )                                      &
                     )

      m33(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmn(i,k,j) )*ss33(i,k,j) &
                       + c1*(   ss33(i,k,j) *ss33(i,k,j)            &
                              + ss13c(i,k,j)*ss13c(i,k,j)          &
                              + ss23c(i,k,j)*ss23c(i,k,j)          &
                              - smnsmn(i,k,j)/3.0                  &
                            )                                      &
                       + c2*(  2.0*(   ss13c(i,k,j)*rr13c(i,k,j)   &
                                     + ss23c(i,k,j)*rr23c(i,k,j)   &
                                   )                               &
                            )                                      &
                     )

    ENDDO
    ENDDO
    ENDDO
 
  ELSE !(config_flags%sfs_opt .EQ. 2) Use TKE

    DO j=j_start,j_end
    DO k=kts,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*ce*delta
      b = c3*delta

      m11(i,k,j) = a*(   2.0*sqrt( tke(i,k,j) )*ss11(i,k,j)            &
                       + b*(                                           &
                               c1*(   ss11(i,k,j) *ss11(i,k,j)         &
                                    + ss12c(i,k,j)*ss12c(i,k,j)        &
                                    + ss13c(i,k,j)*ss13c(i,k,j)        &
                                    - smnsmn(i,k,j)/3.0                &
                                          )                            &
                             + c2*( -2.0*(   ss12c(i,k,j)*rr12c(i,k,j) &
                                           + ss13c(i,k,j)*rr13c(i,k,j) &
                                         )                             &
                                  )                                    &
                           )                                           &
                     )

      m22(i,k,j) = a*(   2.0*sqrt( tke(i,k,j) )*ss22(i,k,j)            &
                       + b*(                                           &
                               c1*(   ss22(i,k,j) *ss22(i,k,j)         &
                                    + ss12c(i,k,j)*ss12c(i,k,j)        &
                                    + ss23c(i,k,j)*ss23c(i,k,j)        &
                                    - smnsmn(i,k,j)/3.0                &
                                            )                          &
                             + c2*(  2.0*(   ss12c(i,k,j)*rr12c(i,k,j) &
                                           - ss23c(i,k,j)*rr23c(i,k,j) &
                                         )                             &
                                  )                                    &
                           )                                           &
                     )

      m33(i,k,j) = a*(   2.0*sqrt( tke(i,k,j) )*ss33(i,k,j)            &
                       + b*(                                           &
                               c1*(   ss33(i,k,j) *ss33(i,k,j)         &
                                    + ss13c(i,k,j)*ss13c(i,k,j)        &
                                    + ss23c(i,k,j)*ss23c(i,k,j)        &
                                    - smnsmn(i,k,j)/3.0                &
                                  )                                    &
                             + c2*(  2.0*(   ss13c(i,k,j)*rr13c(i,k,j) &
                                           + ss23c(i,k,j)*rr23c(i,k,j) &
                                         )                             &
                                  )                                    &
                           )                                           &
                     )
 

    ENDDO
    ENDDO
    ENDDO

  ENDIF

  RETURN

END SUBROUTINE calc_mii

!=============================================================================

SUBROUTINE calc_m12( m12,                          &
                     s11, s22,                     &
                     s12, s13, s23,                &
                     r12, r13, r23, smnsmn,        &
                     tke, rdzw, dx, dy,            &
                     config_flags,                 &
                     ids, ide, jds, jde, kds, kde, &
                     ims, ime, jms, jme, kms, kme, &
                     ips, ipe, jps, jpe, kps, kpe, &
                     its, ite, jts, jte, kts, kte  )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute M12
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( OUT ) &
  :: m12           ! NBA stress element 12               (m2 s-2)

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( IN  ) &
  :: s11         & ! 2*deformation element 11            (s-1)
   , s22         & ! 2*deformation element 22            (s-1)   
   , s12         & ! 2*deformation element 12            (s-1)
   , s13         & ! 2*deformation element 13            (s-1)
   , s23         & ! 2*deformation element 23            (s-1)
   , r12         & ! 2*rotation element 12               (s-1)
   , r13         & ! 2*rotation element 13               (s-1)
   , r23         & ! 2*rotation element 23               (s-1)
   , smnsmn      & ! Smn*Smn                             (s-2)
   , tke         & ! tke                                 (m2 s-2)
   , rdzw          ! 1/dz at w-levels                    (m-1)

  REAL,                                                  INTENT( IN  ) &
  :: dx          & ! grid spacing in x                   (m)
   , dy            ! grid spacing in y                   (m)

  TYPE (grid_config_rec_type),                           INTENT( IN  ) &
  :: config_flags

  INTEGER,                                               INTENT( IN  ) &
  :: ids, ide, jds, jde, kds, kde, &
     ims, ime, jms, jme, kms, kme, &
     ips, ipe, jps, jpe, kps, kpe, &
     its, ite, jts, jte, kts, kte

! LOCAL VARIABLES ------------------------------------------------------------

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! sij/2, rij/2
  :: ss11        & 
   , ss22        &  
   , ss12        &  
   , ss13        & 
   , ss23        & 
   , rr12        & 
   , rr13        & 
   , rr23  


  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! projected to d
  :: tked        & 
   , ss11d       & 
   , ss22d       & 
   , ss13d       & 
   , ss23d       & 
   , rr13d       & 
   , rr23d       &          
   , smnsmnd    

  REAL :: delta, a, b

  INTEGER :: i, j, k, i_start, i_end, j_start, j_end, ktf, je_ext, ie_ext

!-----------------------------------------------------------------------------
!
! Set loop limits,
! taken from /dyn_em/module_diffusion_em.F SUBROUTINE cal_titau_12_21
!
!-----------------------------------------------------------------------------

  ktf = MIN( kte, kde-1 )

! Needs one more point in the x and y directions.

  i_start = its
  i_end   = ite
  j_start = jts
  j_end   = jte

    IF ( config_flags%open_xs .OR. config_flags%specified .OR. &
         config_flags%nested ) i_start = MAX( ids+1, its )
    IF ( config_flags%open_xe .OR. config_flags%specified .OR. &
         config_flags%nested ) i_end   = MIN( ide-1, ite )
    IF ( config_flags%open_ys .OR. config_flags%specified .OR. &
         config_flags%nested ) j_start = MAX( jds+1, jts )
    IF ( config_flags%open_ye .OR. config_flags%specified .OR. &
         config_flags%nested ) j_end   = MIN( jde-1, jte )
      IF ( config_flags%periodic_x ) i_start = its
      IF ( config_flags%periodic_x ) i_end = ite

  je_ext = 1
  ie_ext = 1

  i_end = i_end + ie_ext  
  j_end = j_end + je_ext   

!-----------------------------------------------------------------------------
!
! Divide WRF deformations, which are multiplied by 2, by 2
!
!-----------------------------------------------------------------------------

  DO j=j_start-1,j_end
  DO k=kts,ktf
  DO i=i_start-1,i_end

    ss11(i,k,j)=s11(i,k,j)/2.0
    ss22(i,k,j)=s22(i,k,j)/2.0
    ss12(i,k,j)=s12(i,k,j)/2.0
    ss13(i,k,j)=s13(i,k,j)/2.0
    ss23(i,k,j)=s23(i,k,j)/2.0
    rr12(i,k,j)=r12(i,k,j)/2.0
    rr13(i,k,j)=r13(i,k,j)/2.0
    rr23(i,k,j)=r23(i,k,j)/2.0

  END DO
  END DO
  END DO

  DO j=j_start-1,j_end
  DO i=i_start-1,i_end

    ss13(i,kde,j) = 0.0
    ss23(i,kde,j) = 0.0
    rr13(i,kde,j) = 0.0
    rr23(i,kde,j) = 0.0

  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Project variables to d
!
!-----------------------------------------------------------------------------

  DO j = j_start, j_end
  DO k = kts, ktf
  DO i = i_start, i_end

    tked(i,k,j) = 0.25*( tke(i-1,k  ,j  ) + tke(i  ,k  ,j  ) + &
                         tke(i-1,k  ,j-1) + tke(i  ,k  ,j-1) )

    smnsmnd(i,k,j) = 0.25*( smnsmn(i-1,k  ,j  ) + smnsmn(i  ,k  ,j  ) + &
                            smnsmn(i-1,k  ,j-1) + smnsmn(i  ,k  ,j-1) )

    ss11d(i,k,j) = 0.25*( ss11(i-1,k  ,j  ) + ss11(i  ,k  ,j  ) + &
                          ss11(i-1,k  ,j-1) + ss11(i  ,k  ,j-1) )

    ss22d(i,k,j) = 0.25*( ss22(i-1,k  ,j  ) + ss22(i  ,k  ,j  ) + &
                          ss22(i-1,k  ,j-1) + ss22(i  ,k  ,j-1) )

    ss13d(i,k,j) = 0.25*( ss13(i  ,k+1,j  ) + ss13(i  ,k+1,j-1) + &
                          ss13(i  ,k  ,j  ) + ss13(i  ,k  ,j-1) )

    rr13d(i,k,j) = 0.25*( rr13(i  ,k+1,j  ) + rr13(i  ,k+1,j-1) + &
                          rr13(i  ,k  ,j  ) + rr13(i  ,k  ,j-1) )

    ss23d(i,k,j) = 0.25*( ss23(i  ,k+1,j  ) + ss23(i-1,k+1,j  ) + &
                          ss23(i  ,k  ,j  ) + ss23(i-1,k  ,j  ) )

    rr23d(i,k,j) = 0.25*( rr23(i  ,k+1,j  ) + rr23(i-1,k+1,j  ) + &
                          rr23(i  ,k  ,j  ) + rr23(i-1,k  ,j  ) )

  END DO
  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Calculate M12
!
!-----------------------------------------------------------------------------

  IF ( config_flags%sfs_opt .EQ. 1 ) THEN !Do not use TKE

    DO j=j_start,j_end
    DO k=kts,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*( cs*delta )**2

      m12(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmnd(i,k,j) )*ss12(i,k,j) &
                       + c1*(   ss11d(i,k,j)*ss12(i,k,j)            &
                              + ss22d(i,k,j)*ss12(i,k,j)            &
                              + ss13d(i,k,j)*ss23d(i,k,j)           &
                            )                                       &
                       + c2*(   ss11d(i,k,j)*rr12(i,k,j)            &
                              - ss13d(i,k,j)*rr23d(i,k,j)           & 
                              - ss22d(i,k,j)*rr12(i,k,j)            &
                              - ss23d(i,k,j)*rr13d(i,k,j)           &
                            )                                       &
                      )

    ENDDO
    ENDDO
    ENDDO

  ELSE !(config_flags%sfs_opt .EQ. 2) Use TKE

    DO j=j_start,j_end
    DO k=kts,ktf
    DO i=i_start,i_end 

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*ce*delta
      b = c3*delta

      m12(i,k,j) = a*(   2.0*sqrt( tked(i,k,j) )*s12(i,k,j)     &
                       + b*(                                    &
                               c1*(   ss11d(i,k,j)*ss12(i,k,j)  &
                                    + ss22d(i,k,j)*ss12(i,k,j)  &
                                    + ss13d(i,k,j)*ss23d(i,k,j) &
                                  )                             &
                             + c2*(   ss11d(i,k,j)*rr12(i,k,j)  &
                                    - ss13d(i,k,j)*rr23d(i,k,j) &
                                    - ss22d(i,k,j)*rr12(i,k,j)  &
                                    - ss23d(i,k,j)*rr13d(i,k,j) &
                                  )                             &
                           )                                    &
                     )
    ENDDO
    ENDDO
    ENDDO

  ENDIF

  RETURN

END SUBROUTINE calc_m12

!=============================================================================

SUBROUTINE calc_m13( m13,                          &
                     s11, s33,                     &
                     s12, s13, s23,                &
                     r12, r13, r23, smnsmn,        &
                     tke, rdzw, dx, dy,            &
                     fnm, fnp,                     &
                     config_flags,                 &
                     ids, ide, jds, jde, kds, kde, &
                     ims, ime, jms, jme, kms, kme, &
                     ips, ipe, jps, jpe, kps, kpe, &
                     its, ite, jts, jte, kts, kte  )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute M13
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( OUT ) &
  :: m13           !                                     (m2 s-2)

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( IN  ) &
  :: s11         & ! 2*deformation element 11            (s-1)
   , s33         & ! 2*deformation element 33            (s-1)
   , s12         & ! 2*deformation element 12            (s-1)
   , s13         & ! 2*deformation element 13            (s-1)
   , s23         & ! 2*deformation element 23            (s-1)
   , r12         & ! 2*rotation element 12               (s-1)
   , r13         & ! 2*rotation element 13               (s-1)
   , r23         & ! 2*rotation element 23               (s-1)
   , smnsmn      & ! Smn*Smn                             (s-2)
   , tke         & ! tke                                 (m2 s-2)
   , rdzw          ! 1/dz at w-levels                    (m-1)

  REAL,                                                  INTENT( IN  ) &
  :: dx          & ! grid spacing in x                   (m)
   , dy            ! grid spacing in y                   (m)

  REAL, DIMENSION( kms:kme ),                            INTENT( IN  ) &
  :: fnm         & ! vertical interpolation coefficients
   , fnp           !

  TYPE (grid_config_rec_type),                           INTENT( IN  ) &
  :: config_flags

  INTEGER,                                               INTENT( IN  ) &
  :: ids, ide, jds, jde, kds, kde, &
     ims, ime, jms, jme, kms, kme, &
     ips, ipe, jps, jpe, kps, kpe, &
     its, ite, jts, jte, kts, kte

! LOCAL VARIABLES ------------------------------------------------------------

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! sij/2, rij/2
  :: ss11        & 
   , ss33        &  
   , ss12        &  
   , ss13        & 
   , ss23        & 
   , rr12        & 
   , rr13        & 
   , rr23  

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! projected to e
  :: tkee        & 
   , ss11e       & 
   , ss33e       & 
   , ss12e       & 
   , ss23e       & 
   , rr12e       & 
   , rr23e       &          
   , smnsmne 

  REAL :: delta, a, b

  INTEGER :: i, j, k, i_start, i_end, j_start, j_end, ktf, ie_ext

!-----------------------------------------------------------------------------
!
! Set loop limits,
! taken from /dyn_em/module_diffusion_em.F SUBROUTINE cal_titau_13_31
!
!-----------------------------------------------------------------------------

  ktf = MIN( kte, kde-1 )

! Find ide-1 and jde-1 for averaging to p point.

  i_start = its
  i_end   = ite
  j_start = jts
  j_end   = MIN( jte, jde-1 )

    IF ( config_flags%open_xs .OR. config_flags%specified .OR. &
         config_flags%nested) i_start = MAX( ids+1, its )
    IF ( config_flags%open_xe .OR. config_flags%specified .OR. &
         config_flags%nested) i_end   = MIN( ide-1, ite )
    IF ( config_flags%open_ys .OR. config_flags%specified .OR. &
         config_flags%nested) j_start = MAX( jds+1, jts )
    IF ( config_flags%open_ye .OR. config_flags%specified .OR. &
         config_flags%nested) j_end   = MIN( jde-2, jte )
      IF ( config_flags%periodic_x ) i_start = its
      IF ( config_flags%periodic_x ) i_end = ite

  ie_ext = 1
  i_end = i_end + ie_ext   

!-----------------------------------------------------------------------------
!
! Divide WRF deformations, which are multiplied by 2, by 2
!
!-----------------------------------------------------------------------------

  DO j=j_start,j_end+1
  DO k=kts,ktf
  DO i=i_start-1,i_end

    ss11(i,k,j)=s11(i,k,j)/2.0
    ss33(i,k,j)=s33(i,k,j)/2.0
    ss12(i,k,j)=s12(i,k,j)/2.0
    ss13(i,k,j)=s13(i,k,j)/2.0
    ss23(i,k,j)=s23(i,k,j)/2.0
    rr12(i,k,j)=r12(i,k,j)/2.0
    rr13(i,k,j)=r13(i,k,j)/2.0
    rr23(i,k,j)=r23(i,k,j)/2.0

  END DO
  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Project variables to e
!
!-----------------------------------------------------------------------------

  DO j = j_start, j_end
  DO k = kts+1, ktf
  DO i = i_start, i_end

    tkee(i,k,j) = 0.5*( fnm(k)*( tke(i,k  ,j) + tke(i-1,k  ,j) ) + &
                        fnp(k)*( tke(i,k-1,j) + tke(i-1,k-1,j) ) )

    smnsmne(i,k,j) = 0.5*( fnm(k)*( smnsmn(i,k  ,j) + smnsmn(i-1,k  ,j) ) + &
                           fnp(k)*( smnsmn(i,k-1,j) + smnsmn(i-1,k-1,j) ) )

    ss11e(i,k,j) = 0.5*( fnm(k)*( ss11(i  ,k  ,j  ) + ss11(i-1,k  ,j  ) ) + &
                         fnp(k)*( ss11(i  ,k-1,j  ) + ss11(i-1,k-1,j  ) ) )

    ss33e(i,k,j) = 0.5*( fnm(k)*( ss33(i  ,k  ,j  ) + ss33(i-1,k  ,j  ) ) + &
                         fnp(k)*( ss33(i  ,k-1,j  ) + ss33(i-1,k-1,j  ) ) )
 
    ss12e(i,k,j) = 0.5*( fnm(k)*( ss12(i  ,k  ,j  ) + ss12(i  ,k  ,j+1) ) + &
                         fnp(k)*( ss12(i  ,k-1,j  ) + ss12(i  ,k-1,j+1) ) )

    rr12e(i,k,j) = 0.5*( fnm(k)*( rr12(i  ,k  ,j  ) + rr12(i  ,k  ,j+1) ) + &
                         fnp(k)*( rr12(i  ,k-1,j  ) + rr12(i  ,k-1,j+1) ) )

    ss23e(i,k,j) = 0.25*( ss23(i  ,k  ,j) + ss23(i  ,k  ,j+1) + &
                          ss23(i-1,k  ,j) + ss23(i-1,k  ,j+1) )

    rr23e(i,k,j) = 0.25*( rr23(i  ,k  ,j) + rr23(i  ,k  ,j+1) + &
                          rr23(i-1,k  ,j) + rr23(i-1,k  ,j+1) )

  END DO
  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Calculate M_13
!
!-----------------------------------------------------------------------------


  IF ( config_flags%sfs_opt .EQ. 1 ) THEN !Do not use TKE

    DO j=j_start,j_end
    DO k=kts+1,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*( cs*delta )**2

      m13(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmne(i,k,j) )*ss13(i,k,j) &
                       + c1*(   ss11e(i,k,j)*ss13(i,k,j)            &
                              + ss12e(i,k,j)*ss23e(i,k,j)           &
                              + ss13(i,k,j)*ss33e(i,k,j)            &
                            )                                       &
                       + c2*(   ss11e(i,k,j)*rr13(i,k,j)            &
                              + ss12e(i,k,j)*rr23e(i,k,j)           &
                              - ss23e(i,k,j)*rr12e(i,k,j)           &
                              - ss33e(i,k,j)*rr13(i,k,j)            &
                            )                                       &
                     )

    ENDDO
    ENDDO
    ENDDO

  ELSE !(config_flags%sfs_opt .EQ. 2) Use TKE

    DO j=j_start,j_end
    DO k=kts+1,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*ce*delta
      b = c3*delta

      m13(i,k,j) = a*(   2.0*sqrt( tkee(i,k,j) )*ss13(i,k,j)    &
                       + b*(                                    &
                               c1*(   ss11e(i,k,j)*ss13(i,k,j)  &
                                    + ss12e(i,k,j)*ss23e(i,k,j) &
                                    + ss13(i,k,j)*ss33e(i,k,j)  &
                                  )                             &
                             + c2*(   ss11e(i,k,j)*rr13(i,k,j)  &
                                    + ss12e(i,k,j)*rr23e(i,k,j) &
                                    - ss23e(i,k,j)*rr12e(i,k,j) &
                                    - ss33e(i,k,j)*rr13(i,k,j)  &
                                  )                             &
                           )                                    &
                     )

    ENDDO
    ENDDO
    ENDDO

  ENDIF

  RETURN

END SUBROUTINE calc_m13

!=============================================================================

SUBROUTINE calc_m23( m23,                          &
                     s22, s33,                     &
                     s12, s13, s23,                &
                     r12, r13, r23, smnsmn,        &
                     tke, rdzw, dx, dy,            &
                     fnm, fnp,                     &
                     config_flags,                 &
                     ids, ide, jds, jde, kds, kde, &
                     ims, ime, jms, jme, kms, kme, &
                     ips, ipe, jps, jpe, kps, kpe, &
                     its, ite, jts, jte, kts, kte  )

!-----------------------------------------------------------------------------
!
! PURPOSE: Compute M23
!
!-----------------------------------------------------------------------------

  IMPLICIT NONE

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT( OUT ) &
  :: m23           !                                     (m2 s-2)

  REAL, DIMENSION( ims:ime, kms:kme, jms:jme ),          INTENT(  IN ) &
  :: s22         & ! 2*deformation element 22            (s-1)
   , s33         & ! 2*deformation element 33            (s-1)
   , s12         & ! 2*deformation element 12            (s-1)
   , s13         & ! 2*deformation element 13            (s-1)
   , s23         & ! 2*deformation element 23            (s-1)
   , r12         & ! 2*rotation element 12               (s-1)
   , r13         & ! 2*rotation element 13               (s-1)
   , r23         & ! 2*rotation element 23               (s-1)
   , smnsmn      & ! Smn*Smn                             (s-2)
   , tke         & ! tke                                 (m2 s-2)
   , rdzw          ! 1/dz at w-levels                    (m-1)

  REAL,                                                  INTENT( IN  ) &
  :: dx          & ! grid spacing in x                   (m)
   , dy            ! grid spacing in y                   (m)

  REAL, DIMENSION( kms:kme ),                            INTENT( IN  ) &
  :: fnm         & ! vertical interpolation coefficients
   , fnp           !

  TYPE (grid_config_rec_type),                           INTENT( IN  ) &
  :: config_flags

  INTEGER,                                               INTENT( IN  ) &
  :: ids, ide, jds, jde, kds, kde, &
     ims, ime, jms, jme, kms, kme, &
     ips, ipe, jps, jpe, kps, kpe, &
     its, ite, jts, jte, kts, kte

! LOCAL VARIABLES ------------------------------------------------------------

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! sij/2, rij/2
  :: ss22        & 
   , ss33        &  
   , ss12        &  
   , ss13        & 
   , ss23        & 
   , rr12        & 
   , rr13        & 
   , rr23  

  REAL, DIMENSION( its-1:ite+1, kms:kme, jts-1:jte+1 ) & ! projected to f
  :: tkef        & 
   , ss22f       & 
   , ss33f       & 
   , ss12f       & 
   , ss13f       & 
   , rr12f       & 
   , rr13f       &          
   , smnsmnf    

  REAL :: delta, a, b

  INTEGER :: i, j, k, i_start, i_end, j_start, j_end, ktf, je_ext

!-----------------------------------------------------------------------------
!
! Set loop limits,
! taken from /dyn_em/module_diffusion_em.F SUBROUTINE cal_titau_23_32
!
!-----------------------------------------------------------------------------

  ktf = MIN( kte, kde-1 )

! Find ide-1 and jde-1 for averaging to p point.

  i_start = its
  i_end   = MIN( ite, ide-1 )
  j_start = jts
  j_end   = jte

    IF ( config_flags%open_xs .OR. config_flags%specified .OR. &
         config_flags%nested) i_start = MAX( ids+1, its )
    IF ( config_flags%open_xe .OR. config_flags%specified .OR. &
         config_flags%nested) i_end   = MIN( ide-2, ite )
    IF ( config_flags%open_ys .OR. config_flags%specified .OR. &
         config_flags%nested) j_start = MAX( jds+1, jts )
    IF ( config_flags%open_ye .OR. config_flags%specified .OR. &
         config_flags%nested) j_end   = MIN( jde-1, jte )
      IF ( config_flags%periodic_x ) i_start = its
      IF ( config_flags%periodic_x ) i_end = MIN( ite, ide-1 )

  je_ext = 1
  j_end = j_end + je_ext   

!-----------------------------------------------------------------------------
!
! Divide WRF deformations, which are multiplied by 2, by 2
!
!-----------------------------------------------------------------------------

  DO j=j_start-1,j_end
  DO k=kts,ktf
  DO i=i_start,i_end+1

    ss22(i,k,j)=s22(i,k,j)/2.0
    ss33(i,k,j)=s33(i,k,j)/2.0
    ss12(i,k,j)=s12(i,k,j)/2.0
    ss13(i,k,j)=s13(i,k,j)/2.0
    ss23(i,k,j)=s23(i,k,j)/2.0
    rr12(i,k,j)=r12(i,k,j)/2.0
    rr13(i,k,j)=r13(i,k,j)/2.0
    rr23(i,k,j)=r23(i,k,j)/2.0

  END DO
  END DO
  END DO

!-----------------------------------------------------------------------------
!
! Project variables to f
!
!-----------------------------------------------------------------------------

  DO j = j_start, j_end
  DO k = kts+1, ktf
  DO i = i_start, i_end

    tkef(i,k,j) = 0.5*( fnm(k)*( tke(i  ,k  ,j  ) + tke(i  ,k  ,j-1) ) + &
                        fnp(k)*( tke(i  ,k-1,j  ) + tke(i  ,k-1,j-1) ) )

    smnsmnf(i,k,j) = 0.5*( fnm(k)*( smnsmn(i  ,k  ,j  ) + smnsmn(i  ,k  ,j-1) ) + &
                           fnp(k)*( smnsmn(i  ,k-1,j  ) + smnsmn(i  ,k-1,j-1) ) )

    ss22f(i,k,j) = 0.5*( fnm(k)*( ss22(i  ,k  ,j  ) + ss22(i  ,k  ,j-1) ) + &
                         fnp(k)*( ss22(i  ,k-1,j  ) + ss22(i  ,k-1,j-1) ) )

    ss33f(i,k,j) = 0.5*( fnm(k)*( ss33(i  ,k  ,j  ) + ss33(i  ,k  ,j-1) ) + &
                         fnp(k)*( ss33(i  ,k-1,j  ) + ss33(i  ,k-1,j-1) ) )

    ss12f(i,k,j) = 0.5*( fnm(k)*( ss12(i  ,k  ,j  ) + ss12(i+1,k  ,j  ) ) + &
                         fnp(k)*( ss12(i  ,k-1,j  ) + ss12(i+1,k-1,j  ) ) )

    rr12f(i,k,j) = 0.5*( fnm(k)*( rr12(i  ,k  ,j  ) + rr12(i+1,k  ,j  ) ) + &
                         fnp(k)*( rr12(i  ,k-1,j  ) + rr12(i+1,k-1,j  ) ) )

    ss13f(i,k,j) = 0.25*( ss13(i  ,k  ,j  ) + ss13(i  ,k  ,j-1) + &
                          ss13(i+1,k  ,j-1) + ss13(i+1,k  ,j  ) )

    rr13f(i,k,j) = 0.25*( rr13(i  ,k  ,j  ) + rr13(i  ,k  ,j-1) + &
                          rr13(i+1,k  ,j-1) + rr13(i+1,k  ,j  ) )

  END DO
  END DO
  END DO
 
!-----------------------------------------------------------------------------
!
! Calculate M23
!
!-----------------------------------------------------------------------------

  IF ( config_flags%sfs_opt .EQ. 1 ) THEN !Do not use TKE

    DO j=j_start,j_end
    DO k=kts+1,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*( cs*delta )**2

      m23(i,k,j) = a*(   2.0*sqrt( 2.0*smnsmnf(i,k,j) )*ss23(i,k,j) &
                       + c1*(   ss12f(i,k,j)*ss13f(i,k,j)           &
                              + ss22f(i,k,j)*ss23(i,k,j)            &
                              + ss23(i,k,j) *ss33f(i,k,j)           &
                             )                                      &
                       + c2*(   ss12f(i,k,j)*rr13f(i,k,j)           &
                              + ss22f(i,k,j)*rr23(i,k,j)            &
                              + ss13f(i,k,j)*rr12f(i,k,j)           &
                              - ss33f(i,k,j)*rr23(i,k,j)            &
                            )                                       &
                     )

    ENDDO
    ENDDO
    ENDDO

  ELSE !(config_flags%sfs_opt .EQ. 2) Use TKE

    DO j=j_start,j_end
    DO k=kts+1,ktf
    DO i=i_start,i_end

      delta = ( dx * dy / rdzw(i,k,j) )**0.33333333
      a = -1.0*ce*delta
      b = c3*delta

      m23(i,k,j) = a*(   2.0*sqrt( tkef(i,k,j) )*ss23(i,k,j)    &
                       + b*(                                    &
                               c1*(   ss12f(i,k,j)*ss13f(i,k,j) &
                                    + ss22f(i,k,j)*ss23(i,k,j)  &
                                    + ss23(i,k,j) *ss33f(i,k,j) &
                                  )                             &
                             + c2*(   ss12f(i,k,j)*rr13f(i,k,j) &
                                    + ss22f(i,k,j)*rr23(i,k,j)  &
                                    + ss13f(i,k,j)*rr12f(i,k,j) &
                                    - ss33f(i,k,j)*rr23(i,k,j)  &
                                  )                             &
                           )                                    &
                     )

    ENDDO
    ENDDO
    ENDDO

  ENDIF

  RETURN

END SUBROUTINE calc_m23

!=============================================================================

END MODULE module_sfs_nba
