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
80
81
82
83
84
85
86
87
88
89
90
91
92
|
/*************************************************************************
* Copyright (C) 2010-2012 Tavian Barnes <tavianator@tavianator.com> *
* *
* This file is part of The Dimension Test Suite. *
* *
* The Dimension Test Suite is free software; you can redistribute it *
* and/or modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 3 of the *
* License, or (at your option) any later version. *
* *
* The Dimension Test Suite is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
*************************************************************************/
/**
* @file
* Basic tests of the polynomial root-finder.
*/
#include "tests.h"
#include "../polynomial.c"
/* poly[] = 2*(x + 1)*(x - 1.2345)*(x - 2.3456)*(x - 5)*(x - 100) */
static const double poly[6] = {
[5] = 2.0,
[4] = -215.1602,
[3] = 1540.4520864,
[2] = -2430.5727856,
[1] = -1292.541872,
[0] = 2895.6432,
};
static double roots[5];
static size_t nroots;
#define DMNSN_CLOSE_ENOUGH 1.0e-6
DMNSN_TEST_SETUP(polynomial)
{
nroots = dmnsn_polynomial_solve(poly, 5, roots);
}
DMNSN_TEST(polynomial, finds_positive_roots)
{
ck_assert_int_eq(nroots, 4);
}
DMNSN_TEST(polynomial, local_min_roots)
{
for (size_t i = 0; i < nroots; ++i) {
double evmin = dmnsn_polynomial_evaluate(poly, 5, roots[i] - dmnsn_epsilon);
double ev = dmnsn_polynomial_evaluate(poly, 5, roots[i]);
double evmax = dmnsn_polynomial_evaluate(poly, 5, roots[i] + dmnsn_epsilon);
ck_assert(fabs(ev) < fabs(evmin) && fabs(ev) < fabs(evmax));
}
}
DMNSN_TEST(polynomial, accurate_roots)
{
for (size_t i = 0; i < nroots; ++i) {
double ev = dmnsn_polynomial_evaluate(poly, 5, roots[i]);
ck_assert(fabs(ev) < DMNSN_CLOSE_ENOUGH);
}
}
/* repeated_root[] = (x - 1)^6 */
static const double repeated_root[7] = {
[6] = 1.0,
[5] = -6.0,
[4] = 15.0,
[3] = -20.0,
[2] = 15.0,
[1] = -6.0,
[0] = 1.0,
};
DMNSN_TEST(stability, equal_bounds)
{
double root = dmnsn_bisect_root(repeated_root, 6, 1.0, 1.0);
ck_assert_msg(root == 1.0, "root == %.17g", root);
}
DMNSN_TEST(stability, equal_values_at_bounds)
{
double root = dmnsn_bisect_root(repeated_root, 6, 0.9, 1.1);
ck_assert_msg(fabs(root - 1.0) < dmnsn_epsilon, "root == %.17g", root);
}
|
