/usr/include/shogun/kernel/string/PolyMatchStringKernel.h is in libshogun-dev 3.2.0-7.3build4.
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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | /*
* 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) 1999-2009 Soeren Sonnenburg
* Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
*/
#ifndef _POLYMATCHSTRINGKERNEL_H___
#define _POLYMATCHSTRINGKERNEL_H___
#include <shogun/lib/common.h>
#include <shogun/kernel/string/StringKernel.h>
namespace shogun
{
/** @brief The class PolyMatchStringKernel computes a variant of the polynomial
* kernel on strings of same length.
*
* It is computed as
*
* \f[
* k({\bf x},{\bf x'})= (\sum_{i=0}^L I(x_i=x'_i)+c)^d
* \f]
*
* where I is the indicator function which evaluates to 1 if its argument is
* true and to 0 otherwise.
*
* Note that additional normalisation is applied, i.e.
* \f[
* k'({\bf x}, {\bf x'})=\frac{k({\bf x}, {\bf x'})}{\sqrt{k({\bf x}, {\bf x})k({\bf x'}, {\bf x'})}}
* \f]
*/
class CPolyMatchStringKernel: public CStringKernel<char>
{
public:
/** default constructor */
CPolyMatchStringKernel();
/** constructor
*
* @param size cache size
* @param degree degree
* @param inhomogene is inhomogeneous
*/
CPolyMatchStringKernel(int32_t size, int32_t degree, bool inhomogene);
/** constructor
*
* @param l features of left-hand side
* @param r features of right-hand side
* @param degree degree
* @param inhomogene is inhomogeneous
*/
CPolyMatchStringKernel(
CStringFeatures<char>* l, CStringFeatures<char>* r,
int32_t degree, bool inhomogene);
virtual ~CPolyMatchStringKernel();
/** initialize kernel
*
* @param l features of left-hand side
* @param r features of right-hand side
* @return if initializing was successful
*/
virtual bool init(CFeatures* l, CFeatures* r);
/** clean up kernel */
virtual void cleanup();
/** return what type of kernel we are
*
* @return kernel type POLYMATCH
*/
virtual EKernelType get_kernel_type()
{
return K_POLYMATCH;
}
/** return the kernel's name
*
* @return name PolyMatchString
*/
virtual const char* get_name() const { return "PolyMatchStringKernel"; }
/** enable rescaling by length of feature vector
*
* @param n true to enable
*/
void set_rescaling_enabled(bool n)
{
rescaling=n;
}
/** return rescaling parameter
*
* @return true if rescaling is enabled
*/
bool get_rescaling_enabled()
{
return rescaling;
}
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:
/** degree */
int32_t degree;
/** if kernel is inhomogeneous */
bool inhomogene;
/** true to rescale kernel with string length */
bool rescaling;
};
}
#endif /* _POLYMATCHSTRINGKERNEL_H___ */
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