function filter_combo,struct,A,B

;+
; NAME
;	filter_combo
; PURPOSE
;	To return indices of A/B filter combinations.
; INPUT
;	struct - structure from GET_POINTS
;	A      - number of filter A
;  		  1   Open       Op
;  		  2   NaBan      NB
;  		  3   Quart      Qz
;  		  4   Diffu      Df
;  		  5   WdBan      WB
;  		  6   NuDen      ND
;	B      - number of filter B
;		  1   Open       Op
;		  2   Al.1       A1
;		  3   AlMg       AM
;		  4   Be119      Be
;		  5   Al12       A2
;		  6   Mg3        Mg
; RESTRICTIONS
;	Applicable only to GET_POINTS structures.
; HISTORY
;	25-May-95  LWA
;-

fff=where((struct.filta eq A) and (struct.filtb eq B))

return,fff

end