Added functions to compute covariance matrix.

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

diff --git a/src/data/category.c b/src/data/category.c
index b0424d9f65c054df4631897702d33ab4eae1c57a..33078ce2b45528c1cd518e89fb7c798ae44334b6 100644 (file)
--- a/src/data/category.c
+++ b/src/data/category.c
@@ -41,7 +41,7 @@
 
 #include "xalloc.h"
 
-#define CAT_VALUE_NOT_FOUND -2
+#define CAT_VALUE_NOT_FOUND -1
 
 #define N_INITIAL_CATEGORIES 1
 
@@ -58,6 +58,11 @@ struct cat_vals
                                           track of the number of
                                           values stored.
                                         */
+  size_t *value_counts; /* Element i stores the number of cases for which
+                          the categorical variable has that corresponding 
+                          value. This is necessary for computing covariance
+                          matrices.
+                        */
 };
 
 void
@@ -70,6 +75,7 @@ cat_stored_values_create (const struct variable *v)
       obs_vals->n_categories = 0;
       obs_vals->n_allocated_categories = N_INITIAL_CATEGORIES;
       obs_vals->vals = xnmalloc (N_INITIAL_CATEGORIES, sizeof *obs_vals->vals);
+      obs_vals->value_counts = xnmalloc (N_INITIAL_CATEGORIES, sizeof *obs_vals->value_counts);
       var_set_obs_vals (v, obs_vals);
     }
 }
@@ -80,7 +86,10 @@ cat_stored_values_destroy (struct cat_vals *obs_vals)
   if (obs_vals != NULL)
     {
       if (obs_vals->n_allocated_categories > 0)
-        free (obs_vals->vals);
+       {
+         free (obs_vals->vals);
+         free (obs_vals->value_counts);
+       }
       free (obs_vals);
     }
 }
@@ -108,15 +117,17 @@ cat_value_find (const struct variable *v, const union value *val)
 }
 
 /*
-   Add the new value unless it is already present.
+   Add the new value unless it is already present. Increment the count.
  */
 void
 cat_value_update (const struct variable *v, const union value *val)
 {
   if (var_is_alpha (v))
     {
+      size_t i;
       struct cat_vals *cv = var_get_obs_vals (v);
-      if (cat_value_find (v, val) == CAT_VALUE_NOT_FOUND)
+      i = cat_value_find (v, val);
+      if (i == CAT_VALUE_NOT_FOUND)
        {
          if (cv->n_categories >= cv->n_allocated_categories)
            {
@@ -124,10 +135,17 @@ cat_value_update (const struct variable *v, const union value *val)
              cv->vals = xnrealloc (cv->vals,
                                    cv->n_allocated_categories,
                                    sizeof *cv->vals);
+             cv->value_counts = xnrealloc (cv->value_counts, cv->n_allocated_categories,
+                                           sizeof *cv->value_counts);
            }
          cv->vals[cv->n_categories] = *val;
+         cv->value_counts[cv->n_categories] = 1;
          cv->n_categories++;
        }
+      else
+       {
+         cv->value_counts[i]++;
+       }
     }
 }