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
|
/*
cosine.cpp
Copyright (C) 2015 John Burkardt
Copyright (C) 2019 Richard Knight
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This program 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <ctime>
#include <plugin.h>
using namespace std;
#include "cosine.hpp"
//****************************************************************************80
void cosine_transform_data (csnd::Vector<MYFLT> d, csnd::Vector<MYFLT> c)
//****************************************************************************80
//
// Purpose:
//
// COSINE_TRANSFORM_DATA does a cosine transform on a vector of data.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 27 August 2015
//
// Author:
//
// John Burkardt
//
// Parameters:
//
// Input, integer N, the number of data points.
//
// Input, double D[N], the vector of data.
//
// Output, double COSINE_TRANSFORM_DATA[N], the transform coefficients.
//
{
int n = d.len();
double angle;
int i;
int j;
const double r8_pi = 3.141592653589793;
for ( i = 0; i < n; i++ )
{
c[i] = 0.0;
for ( j = 0; j < n; j++ )
{
angle = r8_pi * ( double ) ( i * ( 2 * j + 1 ) ) / ( double ) ( 2 * n );
c[i] = c[i] + cos ( angle ) * d[j];
}
c[i] = c[i] * sqrt ( 2.0 / ( double ) ( n ) );
}
}
//****************************************************************************80
void cosine_transform_inverse (csnd::Vector<MYFLT> c, csnd::Vector<MYFLT> d)
//****************************************************************************80
//
// Purpose:
//
// COSINE_TRANSFORM_INVERSE does an inverse cosine transform.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 27 August 2015
//
// Author:
//
// John Burkardt
//
// Parameters:
//
// Input, integer N, the number of data points.
//
// Input, double C[N], the vector of transform coefficients
//
// Output, double COSINE_TRANSFORM_INVERSE[N], the original data.
//
{
int n = c.len();
double angle;
int i;
int j;
double r8_pi = 3.141592653589793;
for ( i = 0; i < n; i++ )
{
d[i] = c[0] / 2.0;
for ( j = 1; j < n; j++ )
{
angle = r8_pi * ( double ) ( ( 2 * i + 1 ) * j ) / ( double ) ( 2 * n );
d[i] = d[i] + cos ( angle ) * c[j];
}
d[i] = d[i] * sqrt ( 2.0 / ( double ) ( n ) );
}
}
//****************************************************************************80
|