Added new files resulting from directory restructuring.

[pspp-builds.git] / src / data / category.c

diff --git a/src/data/category.c b/src/data/category.c
new file mode 100644 (file)
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+++ b/src/data/category.c
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+/* PSPP - binary encodings for categorical variables.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+   Written by Jason H Stover <jason@sakla.net>.
+
+   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 2 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, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA. */
+
+/*
+  Functions and data structures to store values of a categorical
+  variable, and to recode those values into binary vectors.
+
+  For some statistical models, it is necessary to change each value
+  of a categorical variable to a vector with binary entries. These
+  vectors are then stored as sub-rows within a matrix during
+  model-fitting. For example, we need functions and data strucutres to map a
+  value, say 'a', of a variable named 'cat_var', to a vector, say (0
+  1 0 0 0), and vice versa.  We also need to be able to map the
+  vector back to the value 'a', and if the vector is a sub-row of a
+  matrix, we need to know which sub-row corresponds to the variable
+  'cat_var'.
+*/
+#include <config.h>
+#include <stdlib.h>
+#include <message.h>
+#include "alloc.h"
+#include "message.h"
+#include "category.h"
+#include "cat-routines.h"
+#include <string.h>
+#include "variable.h"
+
+#define N_INITIAL_CATEGORIES 1
+
+void
+cat_stored_values_create (struct variable *v)
+{
+  if (v->obs_vals == NULL)
+    {
+      v->obs_vals = xmalloc (sizeof (*v->obs_vals));
+      v->obs_vals->n_categories = 0;
+      v->obs_vals->n_allocated_categories = N_INITIAL_CATEGORIES;
+      v->obs_vals->vals =
+       xnmalloc (N_INITIAL_CATEGORIES, sizeof *v->obs_vals->vals);
+    }
+}
+
+void
+cat_stored_values_destroy (struct variable *v)
+{
+  assert (v != NULL);
+  if (v->obs_vals != NULL)
+    {
+      free (v->obs_vals);
+    }
+}
+
+/*
+  Which subscript corresponds to val?
+ */
+size_t
+cat_value_find (const struct variable *v, const union value *val)
+{
+  size_t i;
+  const union value *candidate;
+
+  assert (val != NULL);
+  assert (v != NULL);
+  assert (v->obs_vals != NULL);
+  for (i = 0; i < v->obs_vals->n_categories; i++)
+    {
+      candidate = v->obs_vals->vals + i;
+      assert (candidate != NULL);
+      if (!compare_values (candidate, val, v->width))
+       {
+         return i;
+       }
+    }
+  return CAT_VALUE_NOT_FOUND;
+}
+
+/*
+   Add the new value unless it is already present.
+ */
+void
+cat_value_update (struct variable *v, const union value *val)
+{
+  struct cat_vals *cv;
+
+  if (v->type == ALPHA)
+    {
+      assert (val != NULL);
+      assert (v != NULL);
+      cv = v->obs_vals;
+      if (cat_value_find (v, val) == CAT_VALUE_NOT_FOUND)
+       {
+         if (cv->n_categories >= cv->n_allocated_categories)
+           {
+             cv->n_allocated_categories *= 2;
+             cv->vals = xnrealloc (cv->vals,
+                                   cv->n_allocated_categories,
+                                   sizeof *cv->vals);
+           }
+         cv->vals[cv->n_categories] = *val;
+         cv->n_categories++;
+       }
+    }
+}
+
+union value *
+cat_subscript_to_value (const size_t s, struct variable *v)
+{
+  assert (v->obs_vals != NULL);
+  if (s < v->obs_vals->n_categories)
+    {
+      return (v->obs_vals->vals + s);
+    }
+  else
+    {
+      return NULL;
+    }
+}
+
+/*
+  Return the number of categories of a categorical variable.
+ */
+size_t 
+cat_get_n_categories (const struct variable *v)
+{
+  return v->obs_vals->n_categories;
+}
+