1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2004, 2008, 2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 #include "histogram.h"
20 #include <gl/xalloc.h>
21 #include <libpspp/assertion.h>
22 #include <libpspp/cast.h>
24 #include <gsl/gsl_histogram.h>
25 #include "chart-geometry.h"
30 histogram_add (struct histogram *h, double y, double c)
32 struct statistic *stat = &h->parent;
33 stat->accumulate (stat, NULL, c, 0, y);
39 acc (struct statistic *s, const struct ccase *cx UNUSED, double c, double cc UNUSED, double y)
41 struct histogram *hist = UP_CAST (s, struct histogram, parent);
43 gsl_histogram_accumulate (hist->gsl_hist, y, c);
48 destroy (struct statistic *s)
50 struct histogram *h = UP_CAST (s, struct histogram, parent);
51 gsl_histogram_free (h->gsl_hist);
57 histogram_create (int bins, double min, double max)
59 struct histogram *h = xmalloc (sizeof *h);
60 struct statistic *stat = &h->parent;
61 double upper_limit, lower_limit;
63 double bin_width = chart_rounded_tick ((max - min) / (double) bins);
64 double bin_width_2 = bin_width / 2.0;
66 int n = ceil (max / (bin_width_2) ) ;
70 if ( ! (n % 2 ) ) n++;
71 upper_limit = n * bin_width_2;
73 n = floor (min / (bin_width_2) ) ;
74 if ( ! (n % 2 ) ) n--;
75 lower_limit = n * bin_width_2;
77 h->gsl_hist = gsl_histogram_alloc (bins);
78 gsl_histogram_set_ranges_uniform (h->gsl_hist, lower_limit, upper_limit);
80 stat->accumulate = acc;
81 stat->destroy = destroy;