program mda
c Model data access from the TIEGCM model history files.

	dimension lat_rec(44474), dstruct(74,601)
	integer DYNO, HEELIS, histcnt

	equivalence (lat_rec(2), dstruct)

	iDYNO1= 376 
	iHELIS= 401
	mday= 2
	mhr= 0
	mmin= 0
	histcnt= 0
	loopcnt= 0
	latcnt= 0

	open (unit= 3, file="tiegcm.data", form= "unformatted",
     &   access= "sequential", status= "old")  

	open (unit= 4, file="pot.data", form= "unformatted", 
     &   access= "sequential", status= "new")

	do index= 1, 500 
	  read(3, end= 100) iter, nday, nhr, nmin, dummy 
	  
	  print *,'day ',nday,', hour ',nhr,', minutes ',nmin
	  if (nday .eq. mday .and. nhr .eq. mhr .and. nmin .eq. mmin) then
	    print *,'Found day=',mday,', hour=',mhr,', min= ',mmin
	    histcnt= histcnt+1
	    read (3) dummy
	    do lat_loop= 1, 36
	      latcnt= latcnt+1
c	      buffer in(3,0) (lat_rec(1),lat_rec(44474))
	      read (3) lat_rec
	      do long_loop= 1, 74
		loopcnt= loopcnt+1
	        write(4) dstruct(long_loop, iDYNO1), 
     &  		dstruct(long_loop, iHELIS) 
	      enddo
	    enddo
	   else
	    read (3) dummy
	    do lat_loop= 1, 36
	      print *,'lat_loop= ',lat_loop
	      read (3) dummy
	    enddo
	  endif
	enddo
  100   continue

	print *,'History count is ', histcnt,', loopcnt= ',loopcnt

c;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
c	do lat_loop= 1, 36
c	  do long_loop= 1, 74
c	    print *,'dstruct(',long_loop,',',iDYNO1,')= ', 
c     & 	     dstruct(long_loop, iDYNO1)
c	    print *,'dstruct(',long_loop,',',iHELIS,')= ', 
c     & 	     dstruct(long_loop, iHELIS)
c	  enddo
c	enddo
c;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

c Shut down all files.
	close (3)
	close (4)
	stop
	end