Oops. Neglected to add new files.

[pspp-builds.git] / src / math / tukey-hinges.c

diff --git a/src/math/tukey-hinges.c b/src/math/tukey-hinges.c
new file mode 100644 (file)
index 0000000..95a79c1
--- /dev/null
+++ b/src/math/tukey-hinges.c
@@ -0,0 +1,101 @@
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2008 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 "tukey-hinges.h"
+#include <math/order-stats.h>
+
+#include <gl/xalloc.h>
+#include <libpspp/assertion.h>
+#include <math.h>
+
+void
+tukey_hinges_calculate (const struct tukey_hinges *th, double hinge[3])
+{
+  double a[3];
+  double a_star[3];
+  int i;
+  const struct order_stats *os = &th->parent;
+
+  for (i = 0 ; i < 3 ; ++i)
+    {
+      a_star[i] = os->k[i].tc - os->k[i].cc;
+      a[i] = a_star[i] / os->k[i].c_p1;
+
+      if (a_star[i] < 1)
+       {
+         if (os->k[i].c_p1 >= 1 )
+           {
+             hinge[i] = (1 - a_star[i]) * os->k[i].y
+               + a_star[i] * os->k[i].y_p1;
+           }
+         else
+           {
+             hinge[i] = (1 - a[i]) * os->k[i].y
+               + a[i] * os->k[i].y_p1;
+           }
+       }
+      else
+       {
+         hinge[i] = os->k[i].y_p1;
+       }
+
+    }
+}
+
+static void
+destroy (struct statistic *s)
+{
+  struct order_stats *os = (struct order_stats *) s;
+
+  free (os->k);
+  free (s);
+};
+
+struct statistic *
+tukey_hinges_create (double W, double c_min)
+{
+  double d;
+  struct tukey_hinges *th = xzalloc (sizeof (*th));
+  struct order_stats *os = (struct order_stats *) th;
+  struct statistic *stat = (struct statistic *) th;
+
+  assert (c_min >= 0);
+
+  os->n_k = 3;
+  os->k = xcalloc (sizeof (*os->k), 3);
+
+  if ( c_min >= 1.0)
+    {
+      d = floor ((W + 3) / 2.0) / 2.0;
+
+      os->k[0].tc = d;
+      os->k[1].tc = W/2.0 + 0.5;
+      os->k[2].tc = W + 1 - d;
+    }
+  else
+    {
+      d = floor ((W/c_min + 3.0)/ 2.0) / 2.0 ;
+      os->k[0].tc = d * c_min;
+      os->k[1].tc = (W + c_min) / 2.0;
+      os->k[2].tc = W + c_min * (1 - d);
+    }
+
+
+  stat->destroy = destroy;
+
+  return stat;
+}