New functions is_missing and get_val

Abstract the actions of obtaining the numeric value of a variable
and its missing status, so that it can be more easily applied to
categorical variables and linear variables alike.

diff --git a/src/math/covariance.c b/src/math/covariance.c
index d63159b96d5c3244b85ccd51436170b7e20ec5e9..f3ef7ad4d014bfaeeda4a85da41e52c0e31800e4 100644 (file)
--- a/src/math/covariance.c
+++ b/src/math/covariance.c
@@ -232,6 +232,39 @@ cm_idx (const struct covariance *cov, int i, int j)
   return i - 1 + as;
 }
 
+
+/*
+  Returns true iff the variable corresponding to the Ith element of the covariance matrix 
+   has a missing value for case C
+*/
+static bool
+is_missing (const struct covariance *cov, int i, const struct ccase *c)
+{
+  const struct variable *var = i < cov->n_vars ?
+    cov->vars[i] : 
+    categoricals_get_variable_by_subscript (cov->categoricals, i - cov->n_vars);
+
+  const union value *val = case_data (c, var);
+
+  return var_is_value_missing (var, val, cov->exclude);
+}
+
+
+static double
+get_val (const struct covariance *cov, int i, const struct ccase *c)
+{
+  if ( i < cov->n_vars)
+    {
+      const struct variable *var = cov->vars[i];
+
+      const union value *val = case_data (c, var);
+
+      return val->f;
+    }
+
+  return categoricals_get_binary_by_subscript (cov->categoricals, i - cov->n_vars, c);
+}
+
 static void
 dump_matrix (const gsl_matrix *m)
 {
@@ -263,17 +296,16 @@ covariance_accumulate_pass1 (struct covariance *cov, const struct ccase *c)
 
   for (i = 0 ; i < cov->dim; ++i)
     {
-      const union value *val1 = case_data (c, cov->vars[i]);
+      double v1 = get_val (cov, i, c);
 
-      if ( var_is_value_missing (cov->vars[i], val1, cov->exclude))
+      if ( is_missing (cov, i, c))
        continue;
 
       for (j = 0 ; j < cov->dim; ++j)
        {
          double pwr = 1.0;
-         const union value *val2 = case_data (c, cov->vars[j]);
 
-         if ( var_is_value_missing (cov->vars[j], val2, cov->exclude))
+         if ( is_missing (cov, j, c))
            continue;
 
          for (m = 0 ; m <= MOMENT_MEAN; ++m)
@@ -281,7 +313,7 @@ covariance_accumulate_pass1 (struct covariance *cov, const struct ccase *c)
              double *x = gsl_matrix_ptr (cov->moments[m], i, j);
 
              *x += pwr * weight;
-             pwr *= val1->f;
+             pwr *= v1;
            }
        }
     }
@@ -329,20 +361,20 @@ covariance_accumulate_pass2 (struct covariance *cov, const struct ccase *c)
 
   for (i = 0 ; i < cov->dim; ++i)
     {
-      const union value *val1 = case_data (c, cov->vars[i]);
+      double v1 = get_val (cov, i, c);
 
-      if ( var_is_value_missing (cov->vars[i], val1, cov->exclude))
+      if ( is_missing (cov, i, c))
        continue;
 
       for (j = 0 ; j < cov->dim; ++j)
        {
          int idx;
          double ss ;
-         const union value *val2 = case_data (c, cov->vars[j]);
+         double v2 = get_val (cov, j, c);
 
-         const double s = pow2 (val1->f - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j)) * weight;
+         const double s = pow2 (v1 - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j)) * weight;
 
-         if ( var_is_value_missing (cov->vars[j], val2, cov->exclude))
+         if ( is_missing (cov, j, c))
            continue;
 
          {
@@ -351,9 +383,9 @@ covariance_accumulate_pass2 (struct covariance *cov, const struct ccase *c)
          }
 
          ss = 
-           (val1->f - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j))
+           (v1 - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j))
            * 
-           (val2->f - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j))
+           (v2 - gsl_matrix_get (cov->moments[MOMENT_MEAN], i, j))
            * weight
            ;
 
@@ -391,7 +423,7 @@ covariance_accumulate (struct covariance *cov, const struct ccase *c)
     {
       const union value *val1 = case_data (c, cov->vars[i]);
 
-      if ( var_is_value_missing (cov->vars[i], val1, cov->exclude))
+      if ( is_missing (cov, i, c))
        continue;
 
       for (j = 0 ; j < cov->dim; ++j)
@@ -400,7 +432,7 @@ covariance_accumulate (struct covariance *cov, const struct ccase *c)
          int idx;
          const union value *val2 = case_data (c, cov->vars[j]);
 
-         if ( var_is_value_missing (cov->vars[j], val2, cov->exclude))
+         if ( is_missing (cov, j, c))
            continue;
 
          idx = cm_idx (cov, i, j);