# source:trunk/lib/svm/PolynomialKernelFunction.h@353

Last change on this file since 353 was 353, checked in by Peter, 17 years ago

removed function returning the whole matrix. It is not needed anymore and should not be there for simplistic reasons.

• Property svn:eol-style set to native
• Property svn:keywords set to Author Date Id Revision
File size: 1.4 KB
Line
1// $Id: PolynomialKernelFunction.h 353 2005-06-08 23:28:35Z peter$
2
3#ifndef _theplu_svm_polynomial_kernel_function_
4#define _theplu_svm_polynomial_kernel_function_
5
6#include <c++_tools/svm/KernelFunction.h>
7#include <c++_tools/gslapi/vector.h>
8
9#include <cmath>
10
11
12namespace theplu {
13
14namespace gslapi {
15  class vector;
16}
17
18namespace svm {
19
20  ///
21  /// Class for polynomial kernel calculations
22  ///
23
24
25  class PolynomialKernelFunction : public KernelFunction
26  {
27
28  public:
29    ///
30    ///Constructor taking the order of the polynomial as input. Default is
31    ///order=1 yielding the linear kernel function.
32    ///
33    PolynomialKernelFunction(int = 1);
34
35    ///
36    ///Destructor
37    ///
38    virtual ~PolynomialKernelFunction(void) {};
39
40    ///
41    ///returning the scalar product of two vectors in feature space using the
42    ///polynomial kernel. @return If order is larger than one: \f$(1+x \cdot 43 ///y)^{order} \f$ \n If order is one (linear): \f$x \cdot y \f$
44    ///
45    inline double operator()(const gslapi::vector& a1,
46                             const gslapi::vector& a2) const
47      { return ((order_>1) ? pow(1+a1*a2,order_) : a1*a2); }
48
49
50    ///
51    ///returning the scalar product of two vectors in feature space using the
52    ///polynomial kernel with weights.
53    ///
54    double operator()(const gslapi::vector&, const gslapi::vector&,
55                      const gslapi::vector&, const gslapi::vector&) const;
56
57  private:
58    int order_;
59
60  }; // class PolynomialKernelFunction
61
62}} // of namespace svm and namespace theplu
63
64#endif
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