;-------------------------------------------------------------
;+
; NAME:
;       CUMULATE
; PURPOSE:
;       Array with the cumulative sum of an array.  Integrate.
; CATEGORY:
; CALLING SEQUENCE:
;       out = cumulate(in)
; INPUTS:
;       in = input array.             in
; KEYWORD PARAMETERS:
; OUTPUTS:
;       out = cumulative sum of in.   out
; COMMON BLOCKS:
; NOTES:
; MODIFICATION HISTORY:
;       Ray Sterner,  20 June, 1985.
;	R. Sterner, 26 June, 1991 --- fixed long overflow bug.
;       Johns Hopkins University Applied Physics Laboratory.
;
; Copyright (C) 1985, Johns Hopkins University/Applied Physics Laboratory
; This software may be used, copied, or redistributed as long as it is not
; sold and this copyright notice is reproduced on each copy made.  This
; routine is provided as is without any express or implied warranties
; whatsoever.  Other limitations apply as described in the file disclaimer.txt.
;-
;-------------------------------------------------------------
 
	FUNCTION CUMULATE,IN, help=hlp
 
	if (n_params(0) lt 1) or keyword_set(hlp) then begin
	  print,' Array with the cumulative sum of an array.  Integrate.'
	  print,' out = cumulate(in)'
	  print,'   in = input array.             in'
	  print,'   out = cumulative sum of in.   out'
	  return, -1
	endif
 
	OUT = IN
	OUT(0) = IN(0)
	N = N_ELEMENTS(IN)
	IF N EQ 1 THEN RETURN, OUT
 
	FOR I = 1L, N-1 DO BEGIN
	  OUT(I) = OUT(I-1) + IN(I)
	ENDFOR
 
	RETURN, OUT
 
	END