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EuclideanDistance.cpp
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EuclideanDistance.cpp
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/*
* This software is distributed under BSD 3-clause license (see LICENSE file).
*
* Authors: Saurabh Mahindre, Soumyajit De, Chiyuan Zhang, Viktor Gal,
* Bjoern Esser, Soeren Sonnenburg
*/
#include <shogun/lib/common.h>
#include <shogun/distance/EuclideanDistance.h>
#include <shogun/features/Features.h>
#include <shogun/features/DotFeatures.h>
#include <shogun/features/DenseFeatures.h>
#include <shogun/mathematics/Math.h>
using namespace shogun;
CEuclideanDistance::CEuclideanDistance() : CDistance()
{
register_params();
}
CEuclideanDistance::CEuclideanDistance(CDotFeatures* l, CDotFeatures* r) : CDistance()
{
register_params();
init(l, r);
}
CEuclideanDistance::~CEuclideanDistance()
{
cleanup();
}
bool CEuclideanDistance::init(CFeatures* l, CFeatures* r)
{
cleanup();
CDistance::init(l, r);
REQUIRE(l->has_property(FP_DOT), "Left hand side features must support dot property!\n");
REQUIRE(r->has_property(FP_DOT), "Right hand side features must support dot property!\n");
CDotFeatures* casted_l=static_cast<CDotFeatures*>(l);
CDotFeatures* casted_r=static_cast<CDotFeatures*>(r);
REQUIRE(casted_l->get_dim_feature_space()==casted_r->get_dim_feature_space(),
"Number of dimension mismatch (l:%d vs. r:%d)!\n",
casted_l->get_dim_feature_space(),casted_r->get_dim_feature_space());
precompute_lhs();
if (lhs==rhs)
m_rhs_squared_norms=m_lhs_squared_norms;
else
precompute_rhs();
return true;
}
void CEuclideanDistance::cleanup()
{
reset_precompute();
}
float64_t CEuclideanDistance::compute(int32_t idx_a, int32_t idx_b)
{
float64_t result=0;
CDotFeatures* casted_lhs=static_cast<CDotFeatures*>(lhs);
CDotFeatures* casted_rhs=static_cast<CDotFeatures*>(rhs);
if (lhs->get_feature_class()==rhs->get_feature_class() || lhs->support_compatible_class())
result=casted_lhs->dot(idx_a, casted_rhs, idx_b);
else
result=casted_rhs->dot(idx_b, casted_lhs, idx_a);
result=m_lhs_squared_norms[idx_a]+m_rhs_squared_norms[idx_b]-2*result;
if (disable_sqrt)
return result;
return std::sqrt(result);
}
void CEuclideanDistance::precompute_lhs()
{
REQUIRE(lhs, "Left hand side feature cannot be NULL!\n");
const index_t num_vec=lhs->get_num_vectors();
if (m_lhs_squared_norms.vlen!=num_vec)
m_lhs_squared_norms=SGVector<float64_t>(num_vec);
CDotFeatures* casted_lhs=static_cast<CDotFeatures*>(lhs);
#pragma omp parallel for schedule(static, CPU_CACHE_LINE_SIZE_BYTES)
for(index_t i =0; i<num_vec; ++i)
m_lhs_squared_norms[i]=casted_lhs->dot(i, casted_lhs, i);
}
void CEuclideanDistance::precompute_rhs()
{
REQUIRE(rhs, "Right hand side feature cannot be NULL!\n");
const index_t num_vec=rhs->get_num_vectors();
if (m_rhs_squared_norms.vlen!=num_vec)
m_rhs_squared_norms=SGVector<float64_t>(num_vec);
CDotFeatures* casted_rhs=static_cast<CDotFeatures*>(rhs);
#pragma omp parallel for schedule(static, CPU_CACHE_LINE_SIZE_BYTES)
for(index_t i =0; i<num_vec; ++i)
m_rhs_squared_norms[i]=casted_rhs->dot(i, casted_rhs, i);
}
void CEuclideanDistance::reset_precompute()
{
m_lhs_squared_norms=SGVector<float64_t>();
m_rhs_squared_norms=SGVector<float64_t>();
}
CFeatures* CEuclideanDistance::replace_lhs(CFeatures* l)
{
CFeatures* previous_lhs=CDistance::replace_lhs(l);
precompute_lhs();
if (lhs==rhs)
m_rhs_squared_norms=m_lhs_squared_norms;
return previous_lhs;
}
CFeatures* CEuclideanDistance::replace_rhs(CFeatures* r)
{
CFeatures* previous_rhs=CDistance::replace_rhs(r);
if (lhs==rhs)
m_rhs_squared_norms=m_lhs_squared_norms;
else
precompute_rhs();
return previous_rhs;
}
void CEuclideanDistance::register_params()
{
disable_sqrt=false;
reset_precompute();
SG_ADD(&disable_sqrt, "disable_sqrt", "If sqrt shall not be applied.", MS_NOT_AVAILABLE);
SG_ADD(&m_rhs_squared_norms, "m_rhs_squared_norms", "Squared norms from features of right hand side", MS_NOT_AVAILABLE);
SG_ADD(&m_lhs_squared_norms, "m_lhs_squared_norms", "Squared norms from features of left hand side", MS_NOT_AVAILABLE);
}
float64_t CEuclideanDistance::distance_upper_bounded(int32_t idx_a, int32_t idx_b, float64_t upper_bound)
{
REQUIRE(lhs->get_feature_class()==C_DENSE,
"Left hand side (was %s) has to be CDenseFeatures instance!\n", lhs->get_name());
REQUIRE(rhs->get_feature_class()==C_DENSE,
"Right hand side (was %s) has to be CDenseFeatures instance!\n", rhs->get_name());
REQUIRE(lhs->get_feature_type()==F_DREAL,
"Left hand side (was %s) has to be of double type!\n", lhs->get_name());
REQUIRE(rhs->get_feature_type()==F_DREAL,
"Right hand side (was %s) has to be double type!\n", rhs->get_name());
CDenseFeatures<float64_t>* casted_lhs=static_cast<CDenseFeatures<float64_t>*>(lhs);
CDenseFeatures<float64_t>* casted_rhs=static_cast<CDenseFeatures<float64_t>*>(rhs);
upper_bound*=upper_bound;
SGVector<float64_t> avec=casted_lhs->get_feature_vector(idx_a);
SGVector<float64_t> bvec=casted_rhs->get_feature_vector(idx_b);
REQUIRE(avec.vlen==bvec.vlen, "The vector lengths are not equal (%d vs %d)!\n", avec.vlen, bvec.vlen);
float64_t result=0;
for (int32_t i=0; i<avec.vlen; i++)
{
result+=CMath::sq(avec[i]-bvec[i]);
if (result>upper_bound)
break;
}
if (!disable_sqrt)
result = std::sqrt(result);
return result;
}