function minmax,array,subs,NAN=nan, DIMEN=dimen
;+
; NAME:
;      MINMAX
; PURPOSE:
;      Return a 2 element array giving the minimum and maximum of an array
; EXPLANATION:
;      Using MINMAX() is faster than doing a separate MAX and MIN.
;
;      The procedure MAXMIN in http://www.idlcoyote.com/programs/maxmin.pro
;      has a similar purpose but uses a procedure call rather than a function.
; CALLING SEQUENCE:
;      value = minmax( array, [subs, /NAN, DIMEN= ] )
; INPUTS:
;      array - an IDL numeric scalar, vector or array.
;
; OUTPUTS:
;      value = a two element vector (if DIMEN is not supplied)
;            value[0] = minimum value of array
;            value[1] = maximum value of array
;
;            If the DIMEN keyword is supplied then value will be a 2 x N element
;            array where N is the number of elements in the specified
;            dimension
;              
; OPTIONAL OUTPUT PARAMETER:
;       subs - two-dimensional vector; the first element gives the subscript
;              of the minimum value, the second element gives the subscript
;              of the maximum value.     
;
; OPTIONAL INPUT KEYWORD:
;      /NAN   - Set this keyword to cause the routine to check for occurrences
;            of the IEEE floating-point value NaN in the input data.  Elements 
;            with the value NaN are treated as missing data.
;
;      DIMEN -  integer (either 1 or 2) specifying which dimension of a 2-d 
;            array to  take the minimum and maximum.   Note that (unlike the
;            DIMENSION keyword to the MIN() function) DIMEN is only valid
;            for a 2-d array, larger dimensions are  not supported.  
; EXAMPLE:
;     (1)  Print the minimum and maximum of an image array, im
; 
;            IDL> print, minmax( im )
;
;     (2) Given a 2-dimension array of (echelle) wavelengths w, print the
;         minimum and maximum of each order
;
;         print,minmax(w,dimen=1)
;
; PROCEDURE:
;      The MIN function is used with the MAX keyword
;
; REVISION HISTORY:
;      Written W. Landsman                January, 1990
;      Added NaN keyword.      M. Buie       June 1998
;      Added DIMEN keyword    W. Landsman  January 2002
;      Added SUBSCRIPT_MIN and SUBSCRIPT_MAX  BT Jan 2005
;      Added optional subs output parameter  W. Landsman July 2009
;-
 On_error,2
 compile_opt idl2
 if N_elements(DIMEN) GT 0 then begin
      amin = min(array, MAX = amax, NAN = nan, DIMEN = dimen,cmin,sub=cmax) 
      if arg_present(subs) then subs = transpose([[cmin], [cmax]])
      return, transpose([[amin],[amax] ])
 endif else  begin 
     amin = min( array, MAX = amax, NAN=nan, cmin, sub=cmax)
      if arg_present(subs) then subs = [cmin, cmax]
     return, [ amin, amax ]
 endelse
 end