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src
shogun
kernel
string
PolyMatchStringKernel.cpp
Go to the documentation of this file.
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* Written (W) 1999-2009 Soeren Sonnenburg
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* Copyright (C) 1999-2009 Fraunhofer Institute FIRST and Max-Planck-Society
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*/
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#include <
shogun/lib/common.h
>
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#include <
shogun/io/SGIO.h
>
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#include <
shogun/kernel/string/PolyMatchStringKernel.h
>
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#include <
shogun/kernel/normalizer/SqrtDiagKernelNormalizer.h
>
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#include <
shogun/features/Features.h
>
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#include <
shogun/features/StringFeatures.h
>
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using namespace
shogun;
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CPolyMatchStringKernel::CPolyMatchStringKernel
()
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:
CStringKernel
<char>()
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{
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init
();
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}
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CPolyMatchStringKernel::CPolyMatchStringKernel
(int32_t size, int32_t d,
bool
i)
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:
CStringKernel
<char>(size)
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{
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init
();
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degree
=d;
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inhomogene
=i;
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}
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CPolyMatchStringKernel::CPolyMatchStringKernel
(
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CStringFeatures<char>
* l,
CStringFeatures<char>
* r, int32_t d,
bool
i)
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:
CStringKernel
<char>(10)
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{
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init
();
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degree
=d;
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inhomogene
=i;
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init
(l, r);
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}
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CPolyMatchStringKernel::~CPolyMatchStringKernel
()
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{
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cleanup
();
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}
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bool
CPolyMatchStringKernel::init(
CFeatures
* l,
CFeatures
* r)
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{
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CStringKernel<char>::init
(l, r);
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return
init_normalizer
();
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}
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void
CPolyMatchStringKernel::cleanup
()
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{
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CKernel::cleanup
();
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}
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float64_t
CPolyMatchStringKernel::compute
(int32_t idx_a, int32_t idx_b)
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{
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int32_t i, alen, blen, sum;
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bool
free_avec, free_bvec;
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char
* avec = ((
CStringFeatures<char>
*)
lhs
)->get_feature_vector(idx_a, alen, free_avec);
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char
* bvec = ((
CStringFeatures<char>
*)
rhs
)->get_feature_vector(idx_b, blen, free_bvec);
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ASSERT
(alen==blen);
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for
(i = 0, sum =
inhomogene
; i<alen; i++)
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{
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if
(avec[i]==bvec[i])
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sum++;
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}
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float64_t
result = ((
float64_t
) sum);
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if
(
rescaling
)
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result/=alen;
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((
CStringFeatures<char>
*)
lhs
)->free_feature_vector(avec, idx_a, free_avec);
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((
CStringFeatures<char>
*)
rhs
)->free_feature_vector(bvec, idx_b, free_bvec);
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return
CMath::pow
(result ,
degree
);
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}
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void
CPolyMatchStringKernel::init()
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{
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degree
=0;
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inhomogene
=
false
;
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rescaling
=
false
;
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set_normalizer
(
new
CSqrtDiagKernelNormalizer
());
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SG_ADD
(&
degree
,
"degree"
,
"Degree of poly-kernel."
,
MS_AVAILABLE
);
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SG_ADD
(&
inhomogene
,
"inhomogene"
,
"True for inhomogene poly-kernel."
,
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MS_NOT_AVAILABLE
);
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SG_ADD
(&
rescaling
,
"rescaling"
,
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"True to rescale kernel with string length."
,
MS_AVAILABLE
);
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}
SHOGUN
Machine Learning Toolbox - Documentation