1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 #ifndef _CATEGORICALS__
19 #define _CATEGORICALS__
22 #include "data/missing-values.h"
32 A categorical variable has a finite and usually small number of possible
33 values. The categoricals data structure organizes an array of interactions
34 maong categorical variables, that is, a set of sets of categorical
35 variables. (Both levels of "set" are ordered.)
37 The life cycle of a categoricals object looks like this:
39 1. Create it with categoricals_create(). This fixes the set of interactions
42 2. Pass all of the desired cases through the object with
43 categoricals_update().
45 3. Finalize the object with categoricals_done(). Only at this point may
46 most of the categoricals query functions be called.
48 4. Use the categoricals object as desired.
50 5. Destroy the object with categoricals_destroy().
53 /* Creating and destroying categoricals. */
54 struct categoricals *categoricals_create (struct interaction *const *,
56 const struct variable *wv,
57 enum mv_class fctr_excl);
58 void categoricals_destroy (struct categoricals *);
60 /* Updating categoricals. */
61 void categoricals_update (struct categoricals *, const struct ccase *);
62 void categoricals_done (const struct categoricals *);
63 bool categoricals_is_complete (const struct categoricals *);
65 /* Counting categories.
67 A variable's number of categories is the number of unique values observed in
68 the data passed to categoricals_update().
70 An interaction's number of categories is the number of observed unique
71 values of its variables, which will often be less than the product of its
72 variables' numbers of categories.
74 A categorical object's number of categories is the sum of its interactions'
76 size_t categoricals_n_count (const struct categoricals *, size_t idx);
77 size_t categoricals_n_total (const struct categoricals *);
79 /* Degrees of freedom.
81 A categorical variable with N_CATS categories has N_CATS - 1 degrees of
84 An interaction's degrees of freedom is the product of its variables' degrees
87 A categorical object's degrees of freedom is the sum of its interactions'
88 degrees of freedom. */
89 size_t categoricals_df (const struct categoricals *, size_t idx);
90 size_t categoricals_df_total (const struct categoricals *);
93 bool categoricals_sane (const struct categoricals *cat);
97 These look up an interaction within a categoricals object on the basis of a
98 "subscript". Interaction 0 with DF_0 degrees of freedom is assigned
99 subscripts [0, DF_0 - 1], interaction 1 with DF_1 degrees of freedom is
100 assigned subscripts [DF_0, DF_0 + DF_1 - 1], and so on. The subscripts
101 passed in must be in the range [0, DF_SUM - 1] where DF_SUM is the total
102 number of degrees of freedom for the object, as returned by
103 categoricals_df_total().
105 These functions are intended for covariance matrix routines, where normally
106 1 less than the total number of distinct values of each categorical variable
107 should be considered.
109 These functions may be used on an object only after calling
112 double categoricals_get_weight_by_subscript (const struct categoricals *,
114 const struct interaction *categoricals_get_interaction_by_subscript (
115 const struct categoricals *, int subscript);
116 double categoricals_get_sum_by_subscript (const struct categoricals *,
118 double categoricals_get_dummy_code_for_case (const struct categoricals *,
120 const struct ccase *);
121 double categoricals_get_effects_code_for_case (const struct categoricals *,
123 const struct ccase *);
128 These look up an interaction within a categoricals object on the basis of a
129 "category index". Interaction 0 in CAT with CAT_0 categories has indexes
130 [0, CAT_0 - 1], interaction 1 with CAT_1 categories has indexes [CAT_0,
131 CAT_0 + CAT_1 - 1], and so on. The indexes passed in must be in the range
132 [0, CAT_TOTAL - 1] where CAT_TOTAL is the total number of categories for the
133 object, as returned by categoricals_n_total().
135 These functions are useful for descriptive statistics.
137 These functions may be used on an object only after calling
140 const struct ccase *categoricals_get_case_by_category_real (
141 const struct categoricals *, int iact, int n);
142 void *categoricals_get_user_data_by_category_real (
143 const struct categoricals *, int iact, int n);
145 void *categoricals_get_user_data_by_category (const struct categoricals *,
147 const struct ccase *categoricals_get_case_by_category (
148 const struct categoricals *cat, int subscript);
152 void *(*create) (const void *aux1, void *aux2);
153 void (*update) (const void *aux1, void *aux2, void *user_data,
154 const struct ccase *, double weight);
155 void (*calculate) (const void *aux1, void *aux2, void *user_data);
156 void (*destroy) (const void *aux1, void *aux2, void *user_data);
159 void categoricals_set_payload (struct categoricals *, const struct payload *,
160 const void *aux1, void *aux2);
161 bool categoricals_isbalanced (const struct categoricals *);