1 /* matrix/submatrix_source.c
2 *
3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Gerard Jungman, Brian Gough
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 3 of the License, or (at
8 * your option) any later version.
9 *
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.
14 *
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 02110-1301, USA.
18 */
19
QUALIFIED_VIEW(_gsl_matrix,view)20 QUALIFIED_VIEW(_gsl_matrix,view)
21 FUNCTION (gsl_matrix, submatrix) (QUALIFIED_TYPE(gsl_matrix) * m,
22 const size_t i, const size_t j,
23 const size_t n1, const size_t n2)
24 {
25 QUALIFIED_VIEW(_gsl_matrix,view) view = NULL_MATRIX_VIEW;
26
27 if (i >= m->size1)
28 {
29 GSL_ERROR_VAL ("row index is out of range", GSL_EINVAL, view);
30 }
31 else if (j >= m->size2)
32 {
33 GSL_ERROR_VAL ("column index is out of range", GSL_EINVAL, view);
34 }
35 else if (n1 == 0)
36 {
37 GSL_ERROR_VAL ("first dimension must be non-zero", GSL_EINVAL, view);
38 }
39 else if (n2 == 0)
40 {
41 GSL_ERROR_VAL ("second dimension must be non-zero", GSL_EINVAL, view);
42 }
43 else if (i + n1 > m->size1)
44 {
45 GSL_ERROR_VAL ("first dimension overflows matrix", GSL_EINVAL, view);
46 }
47 else if (j + n2 > m->size2)
48 {
49 GSL_ERROR_VAL ("second dimension overflows matrix", GSL_EINVAL, view);
50 }
51
52 {
53 TYPE(gsl_matrix) s = NULL_MATRIX;
54
55 s.data = m->data + MULTIPLICITY * (i * m->tda + j);
56 s.size1 = n1;
57 s.size2 = n2;
58 s.tda = m->tda;
59 s.block = m->block;
60 s.owner = 0;
61
62 view.matrix = s;
63 return view;
64 }
65 }
66
67