From 90ee3c269580104f2d16d28aeaa565063f6fc1f2 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Fri, 17 Jan 2014 16:52:57 +0100
Subject: RNG overhaul

Previously, we were using random(), which is really really bad.
---
 src/scaling-report.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

(limited to 'src/scaling-report.c')

diff --git a/src/scaling-report.c b/src/scaling-report.c
index 89b2f3f2..85ed0ad2 100644
--- a/src/scaling-report.c
+++ b/src/scaling-report.c
@@ -196,6 +196,7 @@ static void partiality_graph(cairo_t *cr, Crystal **crystals, int n,
 	double pcalcmin[nbins];
 	double pcalcmax[nbins];
 	int num_nondud;
+	gsl_rng *rng;
 
 	show_text_simple(cr, "Observed partiality", -20.0, g_height/2.0,
 	                      NULL, -M_PI_2, J_CENTER);
@@ -223,6 +224,10 @@ static void partiality_graph(cairo_t *cr, Crystal **crystals, int n,
 		num_nondud++;
 	}
 
+	/* The reflections chosen for the graph will be the same every time
+	 * (given the same sequence of input reflections, scalabilities etc) */
+	rng = gsl_rng_alloc(gsl_rng_mt19937);
+
 	cairo_set_source_rgb(cr, 0.0, 0.7, 0.0);
 	prob = 1.0 / num_nondud;
 	for ( i=0; i<n; i++ ) {
@@ -279,13 +284,15 @@ static void partiality_graph(cairo_t *cr, Crystal **crystals, int n,
 
 			bin = nbins * pcalc;
 
-			if ( random_flat(1.0) < prob ) {
+			if ( random_flat(rng, 1.0) < prob ) {
 				plot_point(cr, g_width, g_height, pcalc, pobs);
 			}
 		}
 
 	}
 
+	gsl_rng_free(rng);
+
 	cairo_new_path(cr);
 	cairo_rectangle(cr, 0.0, 0.0, g_width, g_height);
 	cairo_clip(cr);
-- 
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