- Which element of a vector is equal to the value x?
- */
-static size_t
-cat_which_element_eq (const gsl_vector * vec, double x)
-{
- size_t i;
-
- for (i = 0; i < vec->size; i++)
- {
- if (fabs (gsl_vector_get (vec, i) - x) < GSL_DBL_EPSILON)
- {
- return i;
- }
- }
- return CAT_VALUE_NOT_FOUND;
-}
-static int
-cat_is_zero_vector (const gsl_vector * vec)
-{
- size_t i;
-
- for (i = 0; i < vec->size; i++)
- {
- if (gsl_vector_get (vec, i) != 0.0)
- {
- return 0;
- }
- }
- return 1;
-}
-
-/*
- Return the value of v corresponding to the vector vec.
- */
-union value *
-cat_vector_to_value (const gsl_vector * vec, struct variable *v)
-{
- size_t i;
-
- i = cat_which_element_eq (vec, 1.0);
- if (i != CAT_VALUE_NOT_FOUND)
- {
- return cat_subscript_to_value (i + 1, v);
- }
- if (cat_is_zero_vector (vec))
- {
- return cat_subscript_to_value (0, v);
- }
- return NULL;
-}
-
-struct design_matrix *
-design_matrix_create (int n_variables,
- const struct variable *v_variables[],
- const size_t n_data)
-{
- struct design_matrix *dm;
- const struct variable *v;
- size_t i;
- size_t n_cols = 0;
- size_t col;
-
- dm = xmalloc (sizeof *dm);
- dm->vars = xnmalloc (n_variables, sizeof *dm->vars);
- dm->n_vars = n_variables;
-
- for (i = 0; i < n_variables; i++)
- {
- v = v_variables[i];
- assert ((dm->vars + i) != NULL);
- (dm->vars + i)->v = v; /* Allows us to look up the variable from
- the design matrix. */
- (dm->vars + i)->first_column = n_cols;
- if (v->type == NUMERIC)
- {
- n_cols++;
- (dm->vars + i)->last_column = n_cols;
- }
- else if (v->type == ALPHA)
- {
- assert (v->obs_vals != NULL);
- (dm->vars + i)->last_column =
- (dm->vars + i)->first_column + v->obs_vals->n_categories - 2;
- n_cols += v->obs_vals->n_categories - 1;
- }
- }
- dm->m = gsl_matrix_calloc (n_data, n_cols);
- col = 0;
-
- return dm;
-}
-
-void
-design_matrix_destroy (struct design_matrix *dm)
-{
- free (dm->vars);
- gsl_matrix_free (dm->m);
- free (dm);
-}
-
-/*
- Return the index of the variable for the
- given column.
- */
-static size_t
-design_matrix_col_to_var_index (const struct design_matrix *dm, size_t col)
-{
- size_t i;
- struct design_matrix_var v;
-
- for (i = 0; i < dm->n_vars; i++)
- {
- v = dm->vars[i];
- if (v.first_column <= col && col <= v.last_column)
- return (v.v)->index;
- }
- return CAT_INDEX_NOT_FOUND;
-}
-
-/*
- Return a pointer to the variable whose values
- are stored in column col.