FUNCTION AVG,ARRAY,DIMENSION
;+
; NAME:
;	AVG
; PURPOSE:
;	Return the average value of an array, or 1 dimension of an array
; EXPLANATION:
;	Calculate the average value of an array, or calculate the average
;	value over one dimension of an array as a function of all the other
;	dimensions.
;
; CALLING SEQUENCE:
;	RESULT = AVG( ARRAY, [ DIMENSION ] )
;
; INPUTS:
;	ARRAY = Input array.  May be any type except string.
;
; OPTIONAL INPUT PARAMETERS:
;	DIMENSION = Optional dimension to do average over, scalar
;
; OUTPUTS:
;	The average value of the array when called with one parameter.
;
;	If DIMENSION is passed, then the result is an array with all the
;	dimensions of the input array except for the dimension specified,
;	each element of which is the average of the corresponding vector
;	in the input array.
;
;	For example, if A is an array with dimensions of (3,4,5), then the
;	command B = AVG(A,1) is equivalent to
;
;			B = FLTARR(3,5)
;			FOR J = 0,4 DO BEGIN
;				FOR I = 0,2 DO BEGIN
;					B(I,J) = TOTAL( A(I,*,J) ) / 4.
;				ENDFOR
;			ENDFOR
;
; RESTRICTIONS:
;	Dimension specified must be valid for the array passed; otherwise the
;	input array is returned as the output array.
; PROCEDURE:
;	AVG(ARRAY) = TOTAL(ARRAY)/N_ELEMENTS(ARRAY) when called with one
;	parameter.
; MODIFICATION HISTORY:
;	William Thompson	Applied Research Corporation
;	July, 1986		8201 Corporate Drive
;				Landover, MD  20785
;       Converted to Version 2      July, 1990
;       Replace SUM call with TOTAL    W. Landsman    May, 1992
;-
ON_ERROR,2
S = SIZE(ARRAY)
IF S(0) EQ 0 THEN $
	MESSAGE,'Variable must be an array, name= ARRAY'
;
IF N_PARAMS() EQ 1 THEN BEGIN
	AVERAGE = TOTAL(ARRAY) / N_ELEMENTS(ARRAY)
END ELSE BEGIN
	IF ((DIMENSION GE 0) AND (DIMENSION LT S(0))) THEN BEGIN
		AVERAGE = TOTAL(ARRAY,DIMENSION+1) / S(DIMENSION+1)
	END ELSE $
		MESSAGE,'*** Dimension out of range, name= ARRAY'
ENDELSE
;
RETURN, AVERAGE
END