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
|
// Geometric Tools, LLC
// Copyright (c) 1998-2014
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
//
// File Version: 5.0.1 (2010/10/01)
#include "Wm5MathematicsPCH.h"
#include "Wm5ApprPolyFit2.h"
#include "Wm5LinearSystem.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real>
Real* PolyFit2 (int numSamples, const Real* xSamples, const Real* wSamples,
int xDegree)
{
int quantity = xDegree + 1;
Real* coeff = new1<Real>(quantity);
int i0, i1, s;
// Powers of x.
Real** xPower = new2<Real>(2*xDegree+1, numSamples);
for (s = 0; s < numSamples; ++s)
{
xPower[s][0] = (Real)1;
for (i0 = 1; i0 <= 2*xDegree; ++i0)
{
xPower[s][i0] = xSamples[s]*xPower[s][i0-1];
}
}
// Vandermonde matrix and right-hand side of linear system.
GMatrix<Real> A(quantity, quantity);
Real* B = new1<Real>(quantity);
for (i0 = 0; i0 <= xDegree; ++i0)
{
Real sum = (Real)0;
for (s = 0; s < numSamples; ++s)
{
sum += wSamples[s]*xPower[s][i0];
}
B[i0] = sum;
for (i1 = 0; i1 <= xDegree; ++i1)
{
sum = (Real)0;
for (s = 0; s < numSamples; ++s)
{
sum += xPower[s][i0 + i1];
}
A(i0,i1) = sum;
}
}
// Solve for the polynomial coefficients.
bool hasSolution = LinearSystem<Real>().Solve(A, B, coeff);
assertion(hasSolution, "Failed to solve linear system\n");
WM5_UNUSED(hasSolution);
delete1(B);
delete2(xPower);
return coeff;
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_MATHEMATICS_ITEM
float* PolyFit2<float> (int, const float*, const float*, int);
template WM5_MATHEMATICS_ITEM
double* PolyFit2<double> (int, const double*, const double*, int);
//----------------------------------------------------------------------------
}
|
