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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
* Applied Mathematics, Norway.
*
* Contact information: E-mail: tor.dokken@sintef.no
* SINTEF ICT, Department of Applied Mathematics,
* P.O. Box 124 Blindern,
* 0314 Oslo, Norway.
*
* This file is part of SISL.
*
* SISL is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* SISL 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with SISL. If not, see
* <http://www.gnu.org/licenses/>.
*
* In accordance with Section 7(b) of the GNU Affero General Public
* License, a covered work must retain the producer line in every data
* file that is created or manipulated using SISL.
*
* Other Usage
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the SISL library without
* disclosing the source code of your own applications.
*
* This file may be used in accordance with the terms contained in a
* written agreement between you and SINTEF ICT.
*/
#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>
#include <stdexcept>
#include "sisl.h"
#include "GoReadWrite.h"
using namespace std;
namespace {
string OUT_FILE_POINTS = "example14_points.g2";
string OUT_FILE_CURVE = "example14_curve.g2";
string DESCRIPTION =
//==========================================================
"This program demonstrates one of the data reduction \n"
"capabilities in SISL. It generates a dense point set by \n"
"sampling from a predefined curve, and then try to generate \n"
"a curve that fits closely to to these samples, using as few \n"
"control points as possible. (In our case, since we know that \n"
"the points were sampled from a simple curve, we already \n"
"have knowledge about the ideal solution to this problem). \n"
"The sampled points will be saved to the file '" + OUT_FILE_POINTS + "'\n"
"and the generated curve will be saved to the file \n'"
+ OUT_FILE_CURVE + "'.\n\n";
//==========================================================
// information for the sample curve (a simple parabola)
const int number = 3;
const int order = 3;
double coef[] = {0, 0, 0,
1, 1, 0,
2, 0, 0};
double knots[] = {0, 0, 0, 1, 1, 1};
const int num_samples = 500;
}; // end anonymous namespace
//===========================================================================
int main(int avnum, char** vararg)
//===========================================================================
{
cout << '\n' << vararg[0] << ":\n" << DESCRIPTION << endl;
cout << "To proceed, press enter, or ^C to quit." << endl;
getchar();
try {
ofstream os_pts(OUT_FILE_POINTS.c_str());
ofstream os_cv(OUT_FILE_CURVE.c_str());
if (!os_pts || !os_cv) {
throw runtime_error("Unable to open output file.");
}
// generating sample curve
SISLCurve* sample_curve =
newCurve(number, // number of control points
order, // order of spline curve (degree + 1)
knots, // pointer to knot vector (parametrization)
coef, // pointer to coefficient vector (control points)
1, // kind = polynomial B-spline curve
3, // dimension
0); // no copying of information, 'borrow' arrays
if (!sample_curve) {
throw runtime_error("Error occured while generating curve.");
}
// sampling curve densely
vector<double> sampled_point_coords(3 * num_samples);
for (int i = 0; i < num_samples; ++i) {
double parameter = double(i)/(num_samples - 1);
int temp, jstat;
s1227(sample_curve, // the curve to sample from
0, // calculate no derivatives
parameter, // sample in this parameter
&temp, // not used for our purposes (returns parameter interval)
&sampled_point_coords[3 * i], // sampled point written here
&jstat); // status
if (jstat < 0) {
throw runtime_error("Error occured inside call to SISL routine s1227.");
} else if (jstat > 0) {
cerr << "WARNING: warning occured inside call to SISL routine 1227."
<< endl;
}
}
//generating approximating curve
SISLCurve* result_curve = 0;
const double tolerance = 1.0e-5; // pointwise tolerance
const double afctol = 0.1; // number between 0 and 1 describing how tolerance
// is to be distributed in two different steps of the
// algorithm.
const int max_iterations = 150;
vector<double> tolerance_vec(num_samples, tolerance); // same tolerance for all samples
vector<double> emxerr(num_samples);
int jstat = 0;
s1961(&sampled_point_coords[0], // array of points to be approximated
num_samples, // number of sample points
3, // dimension of Euclidean space
2, // flag indicating uniform parametrization
NULL, // we do not use this argument
&tolerance_vec[0], // the pointwise tolerance
0, // number of fixed derivatives at left
0, // number of fixed derivatives at right
1, // flag indicating that we want an open curve
afctol, // distribution of tolerance
max_iterations, // maximum number of iterations in the routine
3, // polynomial order of approximation
&result_curve, // pointer to the generated curve
&emxerr[0], // reporting the max deviation in each point
&jstat); // status variable
if (jstat < 0) {
throw runtime_error("Error occured inside call to SISL routine s1961.");
} else if (jstat > 0) {
cerr << "WARNING: warning occured inside call to SISL routine s1961. \n"
<< endl;
}
cout << "Number of initial data points: " << num_samples << endl;
cout << "Number of control points in final approximation: " << result_curve->in << endl;
cout << "Max pointwise error is : " << *(max_element(emxerr.begin(), emxerr.end()));
cout << endl << endl;
// saving to file
writeGoPoints(num_samples, &sampled_point_coords[0], os_pts);
writeGoCurve(result_curve, os_cv);
// cleaning up
freeCurve(result_curve);
os_pts.close();
os_cv.close();
} catch (exception& e) {
cerr << "Exception thrown: " << e.what() << endl;
return 0;
}
return 1;
};
|
