RFLU_RandomInit.F90

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!******************************************************************************
!
! Purpose: Initializes random number generator in each region
!
! Description: none.
!
! Input:  does not use any data already present
!
! Output: regions(:)%randData is initialized
!
! Notes: none 
!
!  Uses negative seeds.  The procedure to produce them is somewhat awkward
!  because we make no assumptions about the values regions(:)%iRegionGlobal
!
!  The seed 0 is forbidden; positive seeds are used for structured regions.

!******************************************************************************
!
! $Id: RFLU_RandomInit.F90,v 1.5 2008/12/06 08:44:12 mtcampbe Exp $
!
! Copyright: (c) 2003 by the University of Illinois
!
!******************************************************************************

SUBROUTINE rflu_randominit( regions )

  USE moddatatypes
  USE moddatastruct, ONLY : t_region
  USE modglobal,     ONLY : t_global
  USE modrandom,     ONLY : randomseed
  USE moderror
  USE modparameters

  IMPLICIT NONE

! ******************************************************************************
! Definitions and declarations
! ******************************************************************************

! ==============================================================================
! Arguments
! ==============================================================================

  TYPE(t_region), POINTER :: regions(:)

! ==============================================================================
! Locals
! ==============================================================================

  CHARACTER(CHRLEN) :: rcsidentstring
  INTEGER :: iclock1,ilo,ihi,ireg,seed,seedclock

  TYPE(t_global), POINTER :: global

! ******************************************************************************
! Start
! ******************************************************************************

  rcsidentstring = '$RCSfile: RFLU_RandomInit.F90,v $ $Revision: 1.5 $'

  global => regions(1)%global

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

! ******************************************************************************
! Set seed type
! ******************************************************************************

  SELECT CASE(global%randSeedType)
    CASE(rand_seed_type_fixed)
      seedclock = 0
    CASE(rand_seed_type_clock)
      CALL system_clock(iclock1)
      seedclock = -iclock1
  END SELECT ! global%randSeedType

! ******************************************************************************
! Loop over regions
!  Note: seed with negative numbers is used for RFLU
! ******************************************************************************

  ilo = lbound(regions,1)
  ihi = ubound(regions,1)

  DO ireg = ilo,ihi
    seed = ireg-ihi-1 - (ihi-ilo+1) * global%randSeedOffset + seedclock
    IF (seed >= 0) THEN  ! RFLU seeds must be negative
      CALL errorstop( global,err_illegal_value,__line__ )
    ENDIF ! seed

    CALL randomseed(seed,regions(ireg)%randData)
  END DO ! iReg

! ******************************************************************************
! End
! ******************************************************************************

  CALL deregisterfunction( global )

END SUBROUTINE rflu_randominit

!******************************************************************************
!
! RCS Revision history:
!
! $Log: RFLU_RandomInit.F90,v $
! Revision 1.5  2008/12/06 08:44:12  mtcampbe
! Updated license.
!
! Revision 1.4  2008/11/19 22:17:25  mtcampbe
! Added Illinois Open Source License/Copyright
!
! Revision 1.3  2005/12/01 17:09:05  fnajjar
! Added capability for clock-based random seed
!
! Revision 1.2  2003/11/21 22:35:51  fnajjar
! Update Random Number Generator
!
! Revision 1.1  2003/02/17 19:31:11  jferry
! Implemented portable random number generator ModRandom
!
!
!******************************************************************************