;+
; This procedure does a simple (s-r)/r on two rows from the
; opened data file.  This is a very rough first version used just
; so we can start to develop other routines which come downstream.
;
; This currently assumes line mode.  It uses <a
; href="get.html">getrec</a> to fetch each index.  The first index is
; then copied to location 1, the second is copied to location 2 and
; the result is placed in location 0.
;
; @param index1 {in}{required}{type=integer} index 1 points to sig
; @param index2 {in}{required}{type=integer} index 2 points to ref
;
; @examples
;    srr,1,65
;    accum
;    srr,2,66
;    accum
;    ave
;    show
;
; @version $Id: srr.pro,v 1.5 2005/05/30 04:03:43 bgarwood Exp $
;-

pro srr,index1,index2
	getrec,index1
        if (data_valid(!g.s[0]) le 0) then begin
            message,'No valid data found at index1',/info
            return
        endif
	copy,0,1
	dsig = *!g.s[1].data_ptr
	getrec,index2
        if (data_valid(!g.s[0]) le 0) then begin
            message,'No valid data found at index2',/info
            return
        endif
	copy,0,2
	dref = *!g.s[2].data_ptr
	dcal = (dsig - dref) / dref
	*!g.s[0].data_ptr = dcal
	show
end