program  colddate

!**********************************************************************
! *              .      .    .
! * PROGRAM:    colddate
! * PRGMMR:     M. ZUPANSKI     ORG: CIRA/CSU   DATE: 2003-09-16
! *
! * ABSTRACT:   GIVEN THE FCST LENGTH (COLD),  AND CYCLE START DATE,
! *             CALCULATE THE STARTING DATE OF THE COLD FORECAST
! *
! * PROGRAM LOG:
! *
! * 08/18/2003    ..... M. ZUPANSKI:
! *
! **********************************************************************

      character*13 jdate
      character*13 outdate
      character*14 cycle_start_date
      character*14 cycle_date
      integer :: cycle_interval,N_cycles
      integer :: fcst_length

      integer :: diff
      integer :: year,jday,hour
      integer :: outyear,outjday,outhour

!
!      DECLARE NAMELIST
!
     NAMELIST /CYCLE/ cycle_start_date,cycle_interval,N_cycles
     NAMELIST /LENGTH/ fcst_length
!===========================================================

      write(*,*) "read cycle.parm"
      iparm=151
      CLOSE(iparm)
      OPEN(UNIT=iparm,FILE='cycle.parm',FORM='FORMATTED',IOSTAT=IER)
      IF(IER.NE.0)WRITE(*,*) iparm,' OPEN UNIT ERROR IER=',IER
      READ(iparm,CYCLE)

      write(*,*) "read fcst length"
      iparm=152
      CLOSE(iparm)
      OPEN(UNIT=iparm,FILE='fcst_length.cold',FORM='FORMATTED',IOSTAT=IER)
      IF(IER.NE.0)WRITE(*,*) iparm,' OPEN UNIT ERROR IER=',IER
      READ(iparm,LENGTH)

!-----  define appropriate jdate
       call rdate_to_jdate (cycle_start_date,jdate,year,jday,hour)

!-----  diff (sec), fcst_length (min)
       diff=-fcst_length*60

!-----  add the increment
       call add_to_jdate (year,jday,hour,diff,outyear,outjday,outhour)
       call jdate_make_big (outyear,outjday,outhour,outdate)

!-----  define output cycle_date
       call jdate_to_rdate (outdate,cycle_date)

!-----  write out updated 'obs.parm' namelist file
       write(*,*) "CYCLE=",cycle_date

      iparm=51
      CLOSE(iparm)
      OPEN(UNIT=iparm,FILE='cycle_date',FORM='FORMATTED',IOSTAT=IER)
      IF(IER.NE.0)WRITE(*,*) iparm,' OPEN UNIT ERROR IER=',IER
      WRITE(iparm,100) cycle_date
 100  format(a14)
!     CLOSE(UNIT=iparm,STATUS='KEEP')

      stop
      end