1 /* PSPP - Binary encodings for categorical variables.
2 Copyright (C) 2005 Free Software Foundation, Inc.
3 Written by Jason H Stover <jason@sakla.net>.
5 This program is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 This program is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 Functions and data structures to recode categorical variables into
22 vectors and sub-rows of matrices.
24 To fit many types of statistical models, it is necessary
25 to change each value of a categorical variable to a vector with binary
26 entries. These vectors are then stored as sub-rows within a matrix
27 during model-fitting. We need functions and data strucutres to,
28 e.g., map a value, say 'a', of a variable named 'cat_var', to a
29 vector, say (0 1 0 0 0), and vice versa. We also need to be able
30 to map the vector back to the value 'a', and if the vector is a
31 sub-row of a matrix, we need to know which sub-row corresponds to
32 the variable 'cat_var'.
36 #ifndef CAT_ROUTINES_H
37 #define CAT_ROUTINES_H
38 #define CAT_VALUE_NOT_FOUND -2
42 size_t cat_value_find (const struct variable *, const union value *);
44 union value *cat_subscript_to_value (const size_t, struct variable *);
46 void cat_stored_values_create (struct variable *);
48 void cat_value_update (struct variable *, const union value *);
50 void cat_create_value_matrix (struct variable *);
52 void cat_stored_values_destroy (struct variable *);