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src
shogun
kernel
HistogramIntersectionKernel.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) 2010 Koen van de Sande
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* Copyright (C) 2010 Koen van de Sande / University of Amsterdam
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*/
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#include <
shogun/lib/common.h
>
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#include <
shogun/kernel/HistogramIntersectionKernel.h
>
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#include <
shogun/features/Features.h
>
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#include <
shogun/io/SGIO.h
>
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using namespace
shogun;
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CHistogramIntersectionKernel::CHistogramIntersectionKernel
()
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:
CDotKernel
(0), m_beta(1.0)
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{
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register_params
();
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}
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CHistogramIntersectionKernel::CHistogramIntersectionKernel
(int32_t size)
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:
CDotKernel
(size), m_beta(1.0)
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{
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register_params
();
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}
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CHistogramIntersectionKernel::CHistogramIntersectionKernel
(
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CDenseFeatures<float64_t>
* l,
CDenseFeatures<float64_t>
* r,
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float64_t
beta, int32_t size)
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:
CDotKernel
(size), m_beta(beta)
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{
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init
(l,r);
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register_params
();
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}
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CHistogramIntersectionKernel::~CHistogramIntersectionKernel
()
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{
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cleanup
();
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}
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bool
CHistogramIntersectionKernel::init(
CFeatures
* l,
CFeatures
* r)
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{
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bool
result=CDotKernel::init(l,r);
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init_normalizer
();
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return
result;
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}
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float64_t
CHistogramIntersectionKernel::compute
(int32_t idx_a, int32_t idx_b)
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{
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int32_t alen, blen;
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bool
afree, bfree;
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float64_t
* avec=
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((
CDenseFeatures<float64_t>
*)
lhs
)->get_feature_vector(idx_a, alen, afree);
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float64_t
* bvec=
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((
CDenseFeatures<float64_t>
*)
rhs
)->get_feature_vector(idx_b, blen, bfree);
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ASSERT
(alen==blen)
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float64_t
result=0;
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// checking if beta is default or not
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if
(
m_beta
== 1.0)
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{
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// compute standard histogram intersection kernel
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for
(int32_t i=0; i<alen; i++)
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result += (avec[i] < bvec[i]) ? avec[i] : bvec[i];
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}
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else
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{
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//compute generalized histogram intersection kernel
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for
(int32_t i=0; i<alen; i++)
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result +=
CMath::min
(
CMath::pow
(avec[i],
m_beta
),
CMath::pow
(bvec[i],
m_beta
));
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}
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((
CDenseFeatures<float64_t>
*)
lhs
)->free_feature_vector(avec, idx_a, afree);
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((
CDenseFeatures<float64_t>
*)
rhs
)->free_feature_vector(bvec, idx_b, bfree);
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return
result;
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}
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void
CHistogramIntersectionKernel::register_params
()
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{
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SG_ADD
(&
m_beta
,
"beta"
,
"the beta parameter of the kernel"
,
MS_AVAILABLE
);
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}
SHOGUN
Machine Learning Toolbox - Documentation