1 /* lib/linreg/coefficient.c
3 Copyright (C) 2005 Free Software Foundation, Inc.
4 Written by Jason H Stover.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or (at
9 your option) any later version.
11 This program is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
23 Accessor functions for matching coefficients and variables.
26 #include "pspp_linreg.h"
27 #include <gl/xalloc.h>
32 const struct variable *v; /* Variable associated with this
33 coefficient. Note this variable may not
34 be unique. In other words, a
35 coefficient structure may have other
36 v_info's, each with its own variable.
38 const union value *val; /* Value of the variable v which this
39 varinfo refers to. This member is relevant
40 only to categorical variables.
44 void pspp_linreg_coeff_free (struct pspp_linreg_coeff *c)
51 Initialize the variable and value pointers inside the
52 coefficient structures for the linear model.
55 pspp_linreg_coeff_init (pspp_linreg_cache *c, struct design_matrix *X)
60 struct pspp_linreg_coeff *coeff;
62 c->coeff = xnmalloc (X->m->size2 + 1, sizeof (*c->coeff));
63 for (i = 0; i < X->m->size2; i++)
65 j = i + 1; /* The first coefficient is the intercept. */
67 coeff->n_vars = n_vals; /* Currently, no procedures allow interactions.
68 This will have to change when procedures that
69 allow interaction terms are written.
71 coeff->v_info = xnmalloc (coeff->n_vars, sizeof (*coeff->v_info));
72 assert (coeff->v_info != NULL);
73 coeff->v_info->v = (const struct variable *) design_matrix_col_to_var (X, i);
75 if (coeff->v_info->v->type == ALPHA)
78 k = design_matrix_var_to_column (X, coeff->v_info->v);
81 coeff->v_info->val = cat_subscript_to_value (k, (struct variable *) coeff->v_info->v);
86 pspp_linreg_coeff_set_estimate (struct pspp_linreg_coeff *c,
89 c->estimate = estimate;
92 pspp_linreg_coeff_set_std_err (struct pspp_linreg_coeff *c,
98 How many variables are associated with this coefficient?
101 pspp_linreg_coeff_get_n_vars (struct pspp_linreg_coeff *c)
106 Which variable does this coefficient match?
108 const struct variable *
109 pspp_linreg_coeff_get_var (struct pspp_linreg_coeff *c, int i)
111 assert (i < c->n_vars);
112 return (c->v_info + i)->v;
115 Which value is associated with this coefficient/variable comination?
118 pspp_linreg_coeff_get_value (struct pspp_linreg_coeff *c,
119 const struct variable *v)
122 const struct variable *candidate;
124 while (i < c->n_vars)
126 candidate = pspp_linreg_coeff_get_var (c, i);
127 if (v->index == candidate->index)
129 return (c->v_info + i)->val;