/usr/include/shogun/kernel/GaussianShiftKernel.h is in libshogun-dev 1.1.0-4ubuntu2.
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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 | /*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Written (W) 2008 Gunnar Raetsch
* Copyright (C) 2008-2009 Fraunhofer Institute FIRST and Max-Planck-Society
*/
#ifndef _GAUSSIANSHIFTKERNEL_H___
#define _GAUSSIANSHIFTKERNEL_H___
#include <shogun/lib/common.h>
#include <shogun/kernel/GaussianKernel.h>
#include <shogun/features/SimpleFeatures.h>
namespace shogun
{
/** @brief An experimental kernel inspired by the WeightedDegreePositionStringKernel
* and the Gaussian kernel.
*
* It is computed as
*
* \f[
* k({\bf x},{\bf x'})= \exp(-\frac{||{\bf x}-{\bf x'}||^2}{\tau}) +
\sum_{s=1}^{S_{\mathrm{max}}/S_{\mathrm{step}}} \frac{1}{2s}
\exp(-\frac{||{\bf x}_{[1:|{\bf x}|-sS_{\mathrm{step}}]}-{\bf x'}_{[sS_{\mathrm{step}}:|{\bf x}|]}||^2}{\tau}) +
\sum_{s=1}^{S_{max}/S_{step}} \frac{1}{2s}
\exp(-\frac{||{\bf x}_{[sS_{\mathrm{step}}:|{\bf x}|]}-{\bf x'}_{[1:|{\bf x}|-sS_{\mathrm{step}}]}||^2}{\tau}) +
* \f]
*
* where \f$\tau\f$ is the kernel width. The idea is to shift the dimensions of the input vectors against eachother.
* \f$S_{\mathrm{step}}\f$ is the step size (parameter shift_step) of the shifts and
* \f$S_{\mathrm{max}}\f$ (parameter max_shift) is the maximal shift.
*/
class CGaussianShiftKernel: public CGaussianKernel
{
public:
/** default constructor */
CGaussianShiftKernel();
/** constructor
*
* @param size cache size
* @param width width
* @param max_shift maximum shift
* @param shift_step shift step
*/
CGaussianShiftKernel(
int32_t size, float64_t width, int32_t max_shift,
int32_t shift_step);
/** constructor
*
* @param l features of left-hand side
* @param r features of right-hand side
* @param width width
* @param max_shift maximum shift
* @param shift_step shift step
* @param size cache size
*/
CGaussianShiftKernel(
CSimpleFeatures<float64_t>* l, CSimpleFeatures<float64_t>* r,
float64_t width, int32_t max_shift, int32_t shift_step,
int32_t size=10);
virtual ~CGaussianShiftKernel();
/** return what type of kernel we are
*
* @return kernel type GAUSSIANSHIFT
*/
virtual EKernelType get_kernel_type() { return K_GAUSSIANSHIFT; }
/** return the kernel's name
*
* @return name GaussianShift
*/
virtual const char* get_name() const { return "GaussianShiftKernel"; }
protected:
/** compute kernel function for features a and b
* idx_{a,b} denote the index of the feature vectors
* in the corresponding feature object
*
* @param idx_a index a
* @param idx_b index b
* @return computed kernel function at indices a,b
*/
virtual float64_t compute(int32_t idx_a, int32_t idx_b);
private:
void init();
protected:
/** maximum shift */
int32_t max_shift;
/** shift step */
int32_t shift_step;
};
}
#endif /* _GAUSSIANSHIFTKERNEL_H__ */
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