c     file: 'clacwu.for'

      subroutine calcwu

c     + + + PURPOSE + + +
c    This subroutine reads sub-daily wind speeds from a user supplied
c    file or simulates the sub-daily wind speeds if the file is not
c    supplied.

c    programmer: John Tatarko
c    version: 07/28/92

C     Edit History
C     07-Mar-99   wjr   changed unit 8 to luiwsd

c     + + + KEY WORDS + + +
c     wind speed, wind direction, sub-daily wind speed

c     + + + GLOBAL COMMON BLOCKS + + +
*$noereference
      include 'p1unconv.inc'
      include 'p1const.inc'
      include 'p1werm.inc'
      include 'wpath.inc'
      include 'm1sim.inc'
      include 'w1wind.inc'
      include 'file.fi'

c     + + + LOCAL COMMON BLOCKS + + +
      include 'main/main.inc'
*$reference

c     + + + LOCAL VARIABLES + + +
      character line*80

      logical fexist

      integer
     i        day,
     i        i,
     i        jd,
     i        month,
     i        year

c      real    large,
c     r        small

c     + + + LOCAL DEFINITIONS + + +

c   i         - Index on subdaily loop (i=1,ntstep)
c   day       - The current day in the sub-daily wind file.
c   month     - The current month in the sub-daily wind file.
c   year      - The current year in the sub-daily wind file.
c   large     - Variable initialized with small value so that MAX
c               intrinsic function may find the maximum windspeed.
c   line      - This character variable is used to read the header
c               information in the file.
c   small     - Variable initialized with large value so that MIN
c               intrinsic function may find the minimum windspeed.
c   subfil    - This variable holds the subdaily wind information
c               file name.
c   subflg    - This logical variable is a flag to read header
c               information in the sub-daily wind file
c               (if .true., read header; if .false., skip).

c     + + + FUNCTIONS CALLED + + +
      integer julday
      integer   lentrm

c     + + + FUNCTION DEFINITIONS + + +
c     julday  -  Calculates the julian date given the day, month, year

c     + + + OUTPUT FORMATS + + +
 2000 format (2i2,2x,i4,1x,f6.1,24f6.2)
 2005 format (/,' using subdaily wind file:  ',a80)
 2010 format (/,' error reading subdaily wind file: ',a80)
 2020 format (/,' no subdaily wind in file for',2i3,1x,i4,' - it will be
     & generated')

c     + + + END SPECIFICATIONS + + +

c     + + + INITIALIZATION + + +

c      small = 1e20
c      large = -1e20

c    if 'real' sub-daily data exixts - read it
      open(unit = 24, file = rootp(1:lentrm(rootp)) // 'subday.out')
      inquire (file = subfil, exist = fexist)
      if (fexist) then
         write(*,2005) subfil
         if (subflg .eqv. .false.) go to 30
   20    read (luiwsd,'(a)') line
         if (line(1:1) .eq. '#') go to 20
         backspace (unit = luiwsd)
         subflg = .false.
   30    read (luiwsd, *, end = 80, err = 90) day, month, year, awadir,
     &                                   (awu(i), i = 1,ntstep)

c        test for current date
c        write (*,*) 'julday',day, month,year
         jd = julday (day, month, year)
         if (jd .ne. am0jd) then
            write(*,2020)
            go to 50
         end if

c        find max, min, and avg
c         do 40 i = 1, ntstep
c            large = max(large, awu(i))
c            small = min(small, awu(i))
c   40    continue
c         awudmx = large
c         awudmn = small
c         awudav = (awudmx + awudmn) / 2.

         go to 600
   80    backspace (unit= luiwsd)
      end if

c     if 'real' data does not exist - generate
   50 do 60 i = 1, ntstep
         awu(i) = awudav + 0.5 * (awudmx - awudmn) * cos( 2. * pi *
     &            ((ntstep * 24) / ntstep - awhrmx + i) / ntstep)
   60 continue

      go to 600

c     if error reading sub-daily file
   90 write (*,2010) subfil
  500 stop

  600 call caldat (-1,day,month,year)
      write(24,2000) day,month,year,awadir,(awu(i),i=1,ntstep)

      return
      end