distro release 2.1.1

pearl/pearl-fitfuncs.ipf

@@ -893,3 +893,23 @@ function FermiGaussConv(pw, yw, xw) : FitFunc
 	
 	yw = pw[2] * resultwave(xw[p] - pw[3]) + pw[0] + pw[1] * xw[p]
 end
+
+
+/// calculate the shirley background
+///
+///
+function ShirleyBG(w, bg, p1, p2)
+	wave w
+	wave bg
+	variable p1, p2
+	
+	duplicate /o w, bg
+	integrate /meth=1 w /d=bg
+
+	variable bg1 = bg[p1]
+	variable bg2 = bg[p2]
+	bg -= bg1
+	bg /= bg2 - bg1
+	bg *= w[p2] - w[p1]
+	bg += w[p1]
+end