blob: 309e5f57e9ade18106f5750f9c04408e2376410e (
plain)
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
|
/*************************************************************************
* Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The vZ Test Suite. *
* *
* The vZ 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 vZ 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/>. *
*************************************************************************/
#include "vZ.hpp"
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <iomanip>
typedef vZ::EquationSystem<2> Y;
// y'' = y (y == C*exp(x) + D*exp(-x))
//
// Split as:
// y' = v
// v' = y
Y
f(double x, Y y)
{
Y r;
r[0] = y[1];
r[1] = y[0];
return r;
}
int
main()
{
Y y;
y[0] = 1.0;
y[1] = 0.0;
vZ::GenericDP45Integrator<Y> integrator(f);
integrator.tol(1e-6)
.y(y)
.x(0.0)
.h(0.06);
integrator.integrate(2.0);
double actual = integrator.y()[0];
double expected = std::cosh(2.0);
std::cout << std::setprecision(10)
<< "Numerical: " << actual << std::endl
<< "Expected: " << expected << std::endl
<< "h: " << integrator.h() << std::endl
<< "Iterations: " << integrator.iterations() << std::endl
<< "Rejections: " << integrator.rejections() << std::endl;
double error = std::abs(expected - actual)/std::abs(expected);
if (error > 6.0e-7 || !std::isfinite(error)) {
std::cerr << "Error: " << 100.0*error << "%" << std::endl;
return EXIT_FAILURE;
} else {
std::cout << "Error: " << 100.0*error << "%" << std::endl;
return EXIT_SUCCESS;
}
}
|
