RFLO_MinimumTimeStep.F90

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!******************************************************************************
!
! Purpose: calculate the minimum time step for all regions on all processors,
!          compare it to the imposed time step and store the minimum of both.
!
! Description: none.
!
! Input: regions           = data of all grid regions
!        global%dtImposed = user prescribed time step.
!
! Output: global%dtMin = minimum time step.
!
! Notes: none.
!
!******************************************************************************
!
! $Id: RFLO_MinimumTimeStep.F90,v 1.3 2008/12/06 08:44:27 mtcampbe Exp $
!
! Copyright: (c) 2001 by the University of Illinois
!
!******************************************************************************

SUBROUTINE rflo_minimumtimestep( regions )

  USE moddatatypes
  USE moddatastruct, ONLY : t_region
  USE modglobal, ONLY     : t_global
  USE moderror
  USE modmpi
  USE modparameters
  IMPLICIT NONE

! ... parameters
  TYPE(t_region), POINTER :: regions(:)

! ... loop variables
  INTEGER :: ireg

! ... local variables
  REAL(RFREAL) :: cfl, dtmin, dtmintot

  TYPE(t_global), POINTER :: global

!******************************************************************************

  global => regions(1)%global

  CALL registerfunction( global,'RFLO_MinimumTimeStep',&
  'RFLO_MinimumTimeStep.F90' )

! compare imposed and max. stable time step

  dtmin = global%dtImposed

  DO ireg=1,global%nRegions
    IF (regions(ireg)%procid==global%myProcid .AND. &     ! region active and
        regions(ireg)%active==active) THEN                ! on my processor
      cfl   = regions(ireg)%mixtInput%cfl
      dtmin = min(dtmin,global%dtMin*cfl)
    ENDIF   ! active
  ENDDO     ! iReg

  global%dtMin = dtmin

! exhange time step between processors

#ifdef MPI
  CALL mpi_allreduce( global%dtMin,dtmintot,1,mpi_rfreal,mpi_min, &
                      global%mpiComm,global%mpierr )
  IF (global%mpierr /=0 ) CALL errorstop( global,err_mpi_trouble,__line__ )

  global%dtMin = dtmintot
#endif

! finalize

  CALL deregisterfunction( global )

END SUBROUTINE rflo_minimumtimestep

!******************************************************************************
!
! RCS Revision history:
!
! $Log: RFLO_MinimumTimeStep.F90,v $
! Revision 1.3  2008/12/06 08:44:27  mtcampbe
! Updated license.
!
! Revision 1.2  2008/11/19 22:17:38  mtcampbe
! Added Illinois Open Source License/Copyright
!
! Revision 1.1  2004/11/29 20:51:39  wasistho
! lower to upper case
!
! Revision 1.7  2003/05/15 02:57:04  jblazek
! Inlined index function.
!
! Revision 1.6  2002/09/20 22:22:36  jblazek
! Finalized integration into GenX.
!
! Revision 1.5  2002/09/05 17:40:21  jblazek
! Variable global moved into regions().
!
! Revision 1.4  2002/03/18 23:11:33  jblazek
! Finished multiblock and MPI.
!
! Revision 1.3  2002/02/21 23:25:06  jblazek
! Blocks renamed as regions.
!
! Revision 1.2  2002/02/09 01:47:01  jblazek
! Added multi-probe option, residual smoothing, physical time step.
!
! Revision 1.1  2002/01/16 22:03:35  jblazek
! Added time-stepping routines.
!
!******************************************************************************