; an example from ucar.edu
undef("maxrunlen")
function maxrunlen( runs )                     
; find max run length
; Example:
; runs = dim_numrun_n(p.gt.5, 0, 0) ; where p(ntim) or p(ntim,jlat,ilon)
;                                   ; runs(ntim) or runs(ntim,jlat,ilon)
; maxrun = maxrunlen( runs )

local dimr, rankr, maxrun, i, j, indrun
begin
  dimr   = dimsizes(runs)         
  rankr  = dimsizes(dimr)

  if (.not.(rankr.eq.1 .or. rankr.eq.3)) then
      print("maxrunlen: rankr="+rankr+" not yet supported")
      exit
  end if

  if (rankr.eq.1) then
      maxrun = new( 1, "integer", -999)
      indrun = ind( runs.ne.0 )   
      if (.not.ismissing(indrun(0))) then
          maxrun = indrun(dimsizes(indrun)-1) + 1
      else
          maxrun = 0
      end if
  end if

  if (rankr.eq.3) then
      maxrun = new ( dimr(1:rankr-1), "integer", -999)
      do j=0,dimr(1)-1
        do i=0,dimr(2)-1
           indrun = ind( runs(:,j,i).ne.0 )   
           if (.not.ismissing(indrun(0))) then
               maxrun(j,i) = indrun(dimsizes(indrun)-1) + 1
           end if
           delete(indrun)       ; may change size next iteration
        end do
      end do
      copy_VarCoords(runs(0,:,:), maxrun)
  end if

  maxrun@long_name = "max run length"
  return(maxrun)
end