function vang, v1,v2

;+
; NAME:
;  vang
; PURPOSE: (one line)
;  Return the angle between two vectors
; DESCRIPTION:
;  Return the angle (in radians) between two vectors
; CATEGORY:
;  Math
; CALLING SEQUENCE:
;  d = vang(v1,v2)
; INPUTS:
;  v1, v2 - two vector of arbitrary length
; OPTIONAL INPUT PARAMETERS:
;  none
; KEYWORD INPUT PARAMETERS:
;  none
; KEYWORD OUTPUT PARAMETERS:
;  none
; OUTPUTS:
;  angle between v1 and v2
; COMMON BLOCKS:
;  None
; SIDE EFFECTS:
; RESTRICTIONS:
;  None
; PROCEDURE:
; MODIFICATION HISTORY:
;  Written 2000, by Leslie Young, SwRI
;-

 return, acos( vdot( normv(v1), normv(v2) ) )
   
end