1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
// SPDX-FileCopyrightText: Bradley M. Bell <bradbell@seanet.com>
// SPDX-FileContributor: 2003-23 Bradley M. Bell
// ----------------------------------------------------------------------------
/*
{xrst_begin det_of_minor.cpp}
Determinant of a Minor: Example and Test
########################################
{xrst_literal
// BEGIN C++
// END C++
}
{xrst_end det_of_minor.cpp}
*/
// BEGIN C++
# include <vector>
# include <cstddef>
# include <cppad/speed/det_of_minor.hpp>
bool det_of_minor()
{ bool ok = true;
//
// a
// values in the matrix A in row major order
std::vector<double> a = {
1., 2., 3.,
4., 5., 6.,
7., 8., 10.
};
//
// m
// dimension of the matrix A
size_t m = 3;
assert( m * m == a.size() );
//
// r, c
// index vectors set so minor is the entire matrix A
std::vector<size_t> r(m + 1);
std::vector<size_t> c(m + 1);
for(size_t i= 0; i < m; i++)
{ r[i] = i+1;
c[i] = i+1;
}
r[m] = 0;
c[m] = 0;
//
// n
// size of minor that is the entire matrix A
size_t n = m;
//
// det
// evaluate the determinant of A
double det = CppAD::det_of_minor(a, m, n, r, c);
//
// ok
// check the value of the determinant of A
ok &= (det == (double) (1*(5*10-6*8) - 2*(4*10-6*7) + 3*(4*8-5*7)) );
//
// M
// minor where row 0 and column 1 are removed
r[m] = 1; // skip row index 0 by starting at row index 1
c[0] = 2; // skip column index 1 by pointing from index 0 to index 2
n = m - 1; // dimension of the minor M
//
// det
// evaluate determinant of the minor
det = CppAD::det_of_minor(a, m, m-1, r, c);
//
// ok
// check the value of the determinant of the minor
ok &= (det == (double) (4*10-6*7) );
//
return ok;
}
// END C++
|
