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--- robust_refinement_xye [2009/11/18 15:52] – created dch3sl
+++ robust_refinement_xye [2022/11/03 15:08] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== Robust_refinement_xye ======
+Description: Robust refinements in topas
+Contributed by: Kevin H. Stone, Saul H. Lapidus and Peter W. Stephens
+Reference: J. Appl. Cryst. (2009). 42, 385–391; "Implementation and use of robust refinement in powder diffraction in the presence of impurities"
+<code topas>macro Robust_refinement_xye
+{
+/*Rescale peaks according to robust refinement algorithm*/
+r_exp 4.390
+prm test = Get(r_exp);
+prm N = (1/test)^2;
+prm !p0  =0.40007404;
+prm !p1  =-2.5949286;
+prm !p2  =4.3513542;
+prm !p3  =-1.7400101;
+prm !p4  =3.6140845 * 10^-1;
+prm !p5  =-4.5247609 * 10^-2;
+prm !p6  =3.5986364 * 10^-3;
+prm !p7  =-1.8328008 * 10^-4;
+prm !p8  =5.7937184 * 10^-6;
+prm !p9  =-1.035303 * 10^-7;
+prm !p10 =7.9903166 * 10^-10;
+prm t = ((Yobs - Ycalc)/SigmaYobs);
+prm testjohn = If( t < 0.8,
+               (1/Max(SigmaYobs^2, 1))*N,
+               If(t < 21, N*((((((((((p10*t + p9)*t + p8)*t + p7)
+               *t + p6)*t + p5)*t + p4)*t + p3)
+               *t + p2)*t + p1)*t +p0)/(Yobs - Ycalc)^2,
+               N*(2.0131 * Ln(t) + 3.9183)/(Yobs - Ycalc)^2));
+weighting = If( t < 0.8,
+              (1/Max(SigmaYobs^2, 1))*N,
+              If(t < 21, N*((((((((((p10*t + p9)*t + p8)*t + p7)
+              *t + p6)*t + p5)*t + p4)*t + p3)
+              *t + p2)*t + p1)*t +p0)/(Yobs - Ycalc)^2,
+              N*(2.0131 * Ln(t) + 3.9183)/(Yobs - Ycalc)^2));
+recal_weighting_on_iter
+}</code>
+<code topas>macro Robust_refinement_poisson
+{
+'Rescale peaks according to robust refinement algorithm
+'N.B. changed SigmaYobs to Yobs^0.5
+r_exp 4.390
+prm test = Get(r_exp);
+prm N = (1/test)^2;
+prm !p0  =0.40007404;
+prm !p1  =-2.5949286;
+prm !p2  =4.3513542;
+prm !p3  =-1.7400101;
+prm !p4  =3.6140845 * 10^-1;
+prm !p5  =-4.5247609 * 10^-2;
+prm !p6  =3.5986364 * 10^-3;
+prm !p7  =-1.8328008 * 10^-4;
+prm !p8  =5.7937184 * 10^-6;
+prm !p9  =-1.035303 * 10^-7;
+prm !p10 =7.9903166 * 10^-10;
+prm t = ((Yobs - Ycalc)/Yobs^0.5);
+prm testjohn = If( t < 0.8,
+               (1/Max(Yobs, 1))*N,
+               If(t < 21, N*((((((((((p10*t + p9)*t + p8)*t + p7)
+               *t + p6)*t + p5)*t + p4)*t + p3)
+               *t + p2)*t + p1)*t +p0)/(Yobs - Ycalc)^2,
+               N*(2.0131 * Ln(t) + 3.9183)/(Yobs - Ycalc)^2));
+weighting = If( t < 0.8,
+              (1/Max(Yobs, 1))*N,
+              If(t < 21, N*((((((((((p10*t + p9)*t + p8)*t + p7)
+              *t + p6)*t + p5)*t + p4)*t + p3)
+              *t + p2)*t + p1)*t +p0)/(Yobs - Ycalc)^2,
+              N*(2.0131 * Ln(t) + 3.9183)/(Yobs - Ycalc)^2));
+recal_weighting_on_iter
+}</code>