Examine: Added the /PLOT=SPREADLEVEL option

[pspp] / src / output / charts / spreadlevel-plot.c

diff --git a/src/output/charts/spreadlevel-plot.c b/src/output/charts/spreadlevel-plot.c
new file mode 100644 (file)
index 0000000..8fcc0bd
--- /dev/null
+++ b/src/output/charts/spreadlevel-plot.c
@@ -0,0 +1,91 @@
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2012 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
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include "output/charts/spreadlevel-plot.h"
+
+#include "libpspp/cast.h"
+#include "output/chart-item-provider.h"
+
+#include "gl/xalloc.h"
+#include "gl/minmax.h"
+
+#include <math.h>
+#include <float.h>
+
+struct chart_item *
+spreadlevel_plot_create (const char *label, double tx_pwr)
+{
+  struct spreadlevel_plot_chart *sl = xzalloc (sizeof *sl);
+  chart_item_init (&sl->chart_item, &spreadlevel_plot_chart_class, label);
+
+  sl->x_lower = DBL_MAX;
+  sl->x_upper = -DBL_MAX;
+
+  sl->y_lower = DBL_MAX;
+  sl->y_upper = -DBL_MAX;
+
+  sl->tx_pwr = tx_pwr;
+
+  sl->n_data = 0;
+  sl->data = NULL;
+  
+  return &sl->chart_item;
+}
+
+void 
+spreadlevel_plot_add (struct chart_item *ci, double spread, double level)
+{
+  struct spreadlevel_plot_chart *sl = to_spreadlevel_plot_chart (ci);
+
+  if ( sl->tx_pwr == 0)
+    {
+      spread = log (spread);
+      level = log (level);
+    }
+  else
+    {
+      spread = pow (spread, sl->tx_pwr);
+      level = pow (level, sl->tx_pwr);
+    }
+
+  sl->x_lower = MIN (sl->x_lower, level);
+  sl->x_upper = MAX (sl->x_upper, level);
+
+  sl->y_lower = MIN (sl->y_lower, spread);
+  sl->y_upper = MAX (sl->y_upper, spread);
+
+  sl->n_data++;
+  sl->data = xrealloc (sl->data, sizeof (*sl->data) * sl->n_data);
+  sl->data[sl->n_data - 1].x = level;
+  sl->data[sl->n_data - 1].y = spread;
+}
+
+
+static void
+spreadlevel_plot_chart_destroy (struct chart_item *chart_item)
+{
+  struct spreadlevel_plot_chart *sl = to_spreadlevel_plot_chart (chart_item);
+
+  free (sl->data);
+  free (sl);
+}
+
+const struct chart_item_class spreadlevel_plot_chart_class =
+  {
+    spreadlevel_plot_chart_destroy
+  };