HISTOGRAMS: Fix bin width problems on large numbers of bins

[pspp] / src / math / histogram.h

diff --git a/src/math/histogram.h b/src/math/histogram.h
index b2b204ee808098c2bf378ef99e8419c6d4223988..3f8fc3e7e75abdba3fb0fbbfb72ac769939c43b2 100644 (file)
--- a/src/math/histogram.h
+++ b/src/math/histogram.h
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2008 Free Software Foundation, Inc.
+   Copyright (C) 2008, 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
@@ -19,7 +19,7 @@
 
 #include <stddef.h>
 
-#include "statistic.h"
+#include "math/statistic.h"
 
 #include <gsl/gsl_histogram.h>
 
@@ -30,7 +30,13 @@ struct histogram
   gsl_histogram *gsl_hist;
 };
 
-struct statistic * histogram_create (int bins, double max, double min);
+/* 
+   Prepare a histogram for data which lies in the range [min, max)
+   bin_width is a nominal figure only.  It is a hint about what might be
+   an good approximate bin width, but the implementation will adjust it
+   as it thinks fit.
+ */
+struct histogram * histogram_create (double bin_width, double min, double max);
 
 void histogram_add (struct histogram *h, double y, double c);