X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fmath%2Fcorrelation.c;h=e7ebd1f52dbc94ac8469af1c23b68eefe715547d;hb=75e7e4241ba2424c3803548bcf2da0382faf7349;hp=303b48bcfaccb89098fabaa426f628d50323a2a3;hpb=50ac6802fc247814dc4dd6232f6304b928a2d78b;p=pspp

diff --git a/src/math/correlation.c b/src/math/correlation.c
index 303b48bcfa..e7ebd1f52d 100644
--- a/src/math/correlation.c
+++ b/src/math/correlation.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2009 Free Software Foundation, Inc.
+   Copyright (C) 2009, 2011 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -16,20 +16,27 @@
 
 #include <config.h>
 
-#include "correlation.h"
+#include "math/correlation.h"
 
 #include <gsl/gsl_matrix.h>
 #include <gsl/gsl_cdf.h>
 #include <math.h>
-#include <libpspp/misc.h>
-#include "minmax.h"
+
+#include "libpspp/misc.h"
+
+#include "gl/minmax.h"
 
 
 double
 significance_of_correlation (double rho, double w)
 {
   double t = w - 2;
+
+  /* |rho| will mathematically always be in the range [0, 1.0].  Inaccurate
+     calculations sometimes cause it to be slightly greater than 1.0, so
+     force it into the correct range to avoid NaN from sqrt(). */
   t /= 1 - MIN (1, pow2 (rho));
+
   t = sqrt (t);
   t *= rho;