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SigmoidKernel.h
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1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License as published by
4  * the Free Software Foundation; either version 3 of the License, or
5  * (at your option) any later version.
6  *
7  * Written (W) 1999-2010 Soeren Sonnenburg
8  * Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
9  * Copyright (C) 2010 Berlin Institute of Technology
10  */
11 
12 #ifndef _SIGMOIDKERNEL_H___
13 #define _SIGMOIDKERNEL_H___
14 
15 #include <shogun/lib/common.h>
18 
19 namespace shogun
20 {
30 {
31  public:
34 
42 
51  CSigmoidKernel(CDotFeatures* l, CDotFeatures* r, int32_t size,
52  float64_t gamma, float64_t coef0);
53 
54  virtual ~CSigmoidKernel();
55 
62  virtual bool init(CFeatures* l, CFeatures* r);
63 
65  virtual void cleanup();
66 
71  virtual EKernelType get_kernel_type() { return K_SIGMOID; }
72 
77  virtual const char* get_name() const { return "SigmoidKernel"; }
78 
79  protected:
88  virtual float64_t compute(int32_t idx_a, int32_t idx_b)
89  {
90  return tanh(gamma*CDotKernel::compute(idx_a,idx_b)+coef0);
91  }
92 
93  private:
94  void init();
95 
96  protected:
101 };
102 }
103 #endif /* _SIGMOIDKERNEL_H__ */
virtual const char * get_name() const
Definition: SigmoidKernel.h:77
The standard Sigmoid kernel computed on dense real valued features.
Definition: SigmoidKernel.h:29
EKernelType
Definition: Kernel.h:51
virtual void cleanup()
virtual float64_t compute(int32_t idx_a, int32_t idx_b)
Definition: DotKernel.h:121
virtual float64_t compute(int32_t idx_a, int32_t idx_b)
Definition: SigmoidKernel.h:88
Features that support dot products among other operations.
Definition: DotFeatures.h:41
Template class DotKernel is the base class for kernels working on DotFeatures.
Definition: DotKernel.h:29
virtual EKernelType get_kernel_type()
Definition: SigmoidKernel.h:71
double float64_t
Definition: common.h:48
The class Features is the base class of all feature objects.
Definition: Features.h:62
virtual bool init(CFeatures *l, CFeatures *r)

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