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--- alt._gof [2017/02/03 01:42] – created rowlesmr3
+++ alt._gof [2025/09/19 15:18] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== Alternative Goodness of Fit ======
+This is an alternative goodness of fit metric described in [1].
+Macro by: Matthew Rowles. All the actual work: Julian Henn
+[1] [[https://doi.org/10.1107/S2053273316013206|Henn, J. 2016. "An Alternative to the Goodness of Fit." Acta Crystallographica A 72 (6): 696-703.]].
+<code topas>
+''alternative GOF value as defined in Henn, J. 2016. "An Alternative to the Goodness of Fit." Acta Crystallographica A 72 (6): 696-703.
+macro aGoFs(val) {
+	prm !N_par = Get(number_independent_parameters);
+	xdd_sum !N_ref = Yobs-Yobs + 1; ''this is the number of datapoints
+	xdd_sum !delta_sq = (Yobs - Ycalc)^2;
+	xdd_sum !sigma_sq_1 = Yobs;
+	xdd_sum !sigma_sq_2 = SigmaYobs^2;
+	''if SigmaYobs is not defined, then this makes sure you use sigma = sqrt(Yobs)
+	prm sigma_sq = If(sigma_sq_2 == 0, sigma_sq_1,sigma_sq_2);
+	chi2 = (N_ref/(N_ref - N_par)) (delta_sq / sigma_sq); : val
+}
+</code>