jubatus::core::nearest_neighbor Namespace Reference

Classes
class	bit_vector_nearest_neighbor_base
class	euclid_lsh
class	lsh
class	minhash
class	nearest_neighbor_base
class	nearest_neighbor_exception
class	unimplemented_exception

Functions
storage::bit_vector	binarize (const std::vector< float > &proj)
bit_vector	binarize (const vector< float > &proj)
bit_vector	cosine_lsh (const common::sfv_t &sfv, uint32_t hash_num)
shared_ptr< nearest_neighbor_base >	create_nearest_neighbor (const std::string &name, const common::jsonconfig::config &config, shared_ptr< storage::column_table > table, const std::string &id)
jubatus::util::lang::shared_ptr< nearest_neighbor_base >	create_nearest_neighbor (const std::string &name, const common::jsonconfig::config &config, jubatus::util::lang::shared_ptr< storage::column_table > table, const std::string &id)
vector< float >	random_projection (const common::sfv_t &sfv, uint32_t hash_num)
void	ranking_hamming_bit_vectors (const bit_vector &query, const const_bit_vector_column &bvs, vector< pair< uint64_t, float > > &ret, uint64_t ret_num)
void	ranking_hamming_bit_vectors (const storage::bit_vector &query, const storage::const_bit_vector_column &bvs, std::vector< std::pair< uint64_t, float > > &ret, uint64_t ret_num)

Function Documentation

storage::bit_vector jubatus::core::nearest_neighbor::binarize

(

const std::vector< float > &

proj

)

bit_vector jubatus::core::nearest_neighbor::binarize

(

const vector< float > &

proj

)

Definition at line 43 of file lsh_function.cpp.

References jubatus::core::storage::bit_vector_base< bit_base >::set_bit().

Referenced by cosine_lsh(), and jubatus::core::storage::lsh_index_storage::make_entry().

                                               {
  bit_vector bv(proj.size());
  for (size_t i = 0; i < proj.size(); ++i) {
    if (proj[i] > 0) {
      bv.set_bit(i);
    }
  }
  return bv;
}

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storage::bit_vector jubatus::core::nearest_neighbor::cosine_lsh	(	const common::sfv_t &	sfv,
		uint32_t	hash_num
	)

Definition at line 53 of file lsh_function.cpp.

References binarize(), and random_projection().

Referenced by jubatus::core::nearest_neighbor::lsh::hash(), and jubatus::core::nearest_neighbor::euclid_lsh::set_row().

                                                                 {
  return binarize(random_projection(sfv, hash_num));
}

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shared_ptr<nearest_neighbor_base> jubatus::core::nearest_neighbor::create_nearest_neighbor	(	const std::string &	name,
		const common::jsonconfig::config &	config,
		shared_ptr< storage::column_table >	table,
		const std::string &	id
	)

Definition at line 32 of file nearest_neighbor_factory.cpp.

References jubatus::core::common::jsonconfig::config_cast_check(), and JUBATUS_EXCEPTION.

Referenced by jubatus::core::anomaly::anomaly_factory::create_anomaly(), jubatus::core::classifier::classifier_factory::create_classifier(), and jubatus::core::recommender::recommender_factory::create_recommender().

                         {

  using common::jsonconfig::config_cast_check;

  if (name == "euclid_lsh") {
    return shared_ptr<nearest_neighbor_base>(
        new euclid_lsh(config_cast_check<euclid_lsh::config>(config),
                       table,
                       id));
  } else if (name == "lsh") {
    return shared_ptr<nearest_neighbor_base>(
        new lsh(config_cast_check<lsh::config>(config), table, id));
  } else if (name == "minhash") {
    return shared_ptr<nearest_neighbor_base>(
        new minhash(config_cast_check<minhash::config>(config), table, id));
  } else {
    throw JUBATUS_EXCEPTION(common::unsupported_method(name));
  }
}

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jubatus::util::lang::shared_ptr<nearest_neighbor_base> jubatus::core::nearest_neighbor::create_nearest_neighbor	(	const std::string &	name,
		const common::jsonconfig::config &	config,
		jubatus::util::lang::shared_ptr< storage::column_table >	table,
		const std::string &	id
	)

std::vector< float > jubatus::core::nearest_neighbor::random_projection	(	const common::sfv_t &	sfv,
		uint32_t	hash_num
	)

Definition at line 31 of file lsh_function.cpp.

References jubatus::core::common::hash_util::calc_string_hash().

Referenced by cosine_lsh().

                                                                           {
  vector<float> proj(hash_num);
  for (size_t i = 0; i < sfv.size(); ++i) {
    const uint32_t seed = common::hash_util::calc_string_hash(sfv[i].first);
    jubatus::util::math::random::mtrand rnd(seed);
    for (uint32_t j = 0; j < hash_num; ++j) {
      proj[j] += sfv[i].second * rnd.next_gaussian();
    }
  }
  return proj;
}

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void jubatus::core::nearest_neighbor::ranking_hamming_bit_vectors	(	const bit_vector &	query,
		const const_bit_vector_column &	bvs,
		vector< pair< uint64_t, float > > &	ret,
		uint64_t	ret_num
	)

Definition at line 34 of file bit_vector_ranking.cpp.

References jubatus::core::clustering::dist(), jubatus::core::storage::fixed_size_heap< T, Comp >::get_sorted(), and jubatus::core::storage::fixed_size_heap< T, Comp >::push().

Referenced by jubatus::core::nearest_neighbor::bit_vector_nearest_neighbor_base::neighbor_row_from_hash().

                      {
  storage::fixed_size_heap<pair<uint32_t, uint64_t> > heap(ret_num);
  for (uint64_t i = 0; i < bvs.size(); ++i) {
    const size_t dist = query.calc_hamming_distance(bvs[i]);
    heap.push(make_pair(dist, i));
  }

  vector<pair<uint32_t, uint64_t> > sorted;
  heap.get_sorted(sorted);

  ret.clear();
  const float denom = query.bit_num();
  for (size_t i = 0; i < sorted.size(); ++i) {
    ret.push_back(make_pair(sorted[i].second, sorted[i].first / denom));
  }
}

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void jubatus::core::nearest_neighbor::ranking_hamming_bit_vectors	(	const storage::bit_vector &	query,
		const storage::const_bit_vector_column &	bvs,
		std::vector< std::pair< uint64_t, float > > &	ret,
		uint64_t	ret_num
	)