%PDF-
%PDF-
Mini Shell
Mini Shell
// Boost.Geometry Index
//
// R-tree distance (knn, path, etc. ) query visitor implementation
//
// Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
//
// This file was modified by Oracle on 2019.
// Modifications copyright (c) 2019 Oracle and/or its affiliates.
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
//
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GEOMETRY_INDEX_DETAIL_RTREE_VISITORS_DISTANCE_QUERY_HPP
#define BOOST_GEOMETRY_INDEX_DETAIL_RTREE_VISITORS_DISTANCE_QUERY_HPP
namespace boost { namespace geometry { namespace index {
namespace detail { namespace rtree { namespace visitors {
template <typename Value, typename Translator, typename DistanceType, typename OutIt>
class distance_query_result
{
public:
typedef DistanceType distance_type;
inline explicit distance_query_result(size_t k, OutIt out_it)
: m_count(k), m_out_it(out_it)
{
BOOST_GEOMETRY_INDEX_ASSERT(0 < m_count, "Number of neighbors should be greater than 0");
m_neighbors.reserve(m_count);
}
inline void store(Value const& val, distance_type const& curr_comp_dist)
{
if ( m_neighbors.size() < m_count )
{
m_neighbors.push_back(std::make_pair(curr_comp_dist, val));
if ( m_neighbors.size() == m_count )
std::make_heap(m_neighbors.begin(), m_neighbors.end(), neighbors_less);
}
else
{
if ( curr_comp_dist < m_neighbors.front().first )
{
std::pop_heap(m_neighbors.begin(), m_neighbors.end(), neighbors_less);
m_neighbors.back().first = curr_comp_dist;
m_neighbors.back().second = val;
std::push_heap(m_neighbors.begin(), m_neighbors.end(), neighbors_less);
}
}
}
inline bool has_enough_neighbors() const
{
return m_count <= m_neighbors.size();
}
inline distance_type greatest_comparable_distance() const
{
// greatest distance is in the first neighbor only
// if there is at least m_count values found
// this is just for safety reasons since is_comparable_distance_valid() is checked earlier
// TODO - may be replaced by ASSERT
return m_neighbors.size() < m_count
? (std::numeric_limits<distance_type>::max)()
: m_neighbors.front().first;
}
inline size_t finish()
{
typedef typename std::vector< std::pair<distance_type, Value> >::const_iterator neighbors_iterator;
for ( neighbors_iterator it = m_neighbors.begin() ; it != m_neighbors.end() ; ++it, ++m_out_it )
*m_out_it = it->second;
return m_neighbors.size();
}
private:
inline static bool neighbors_less(
std::pair<distance_type, Value> const& p1,
std::pair<distance_type, Value> const& p2)
{
return p1.first < p2.first;
}
size_t m_count;
OutIt m_out_it;
std::vector< std::pair<distance_type, Value> > m_neighbors;
};
template
<
typename MembersHolder,
typename Predicates,
unsigned DistancePredicateIndex,
typename OutIter
>
class distance_query
: public MembersHolder::visitor_const
{
public:
typedef typename MembersHolder::value_type value_type;
typedef typename MembersHolder::box_type box_type;
typedef typename MembersHolder::parameters_type parameters_type;
typedef typename MembersHolder::translator_type translator_type;
typedef typename MembersHolder::allocators_type allocators_type;
typedef typename index::detail::strategy_type<parameters_type>::type strategy_type;
typedef typename MembersHolder::node node;
typedef typename MembersHolder::internal_node internal_node;
typedef typename MembersHolder::leaf leaf;
typedef index::detail::predicates_element<DistancePredicateIndex, Predicates> nearest_predicate_access;
typedef typename nearest_predicate_access::type nearest_predicate_type;
typedef typename indexable_type<translator_type>::type indexable_type;
typedef index::detail::calculate_distance<nearest_predicate_type, indexable_type, strategy_type, value_tag> calculate_value_distance;
typedef index::detail::calculate_distance<nearest_predicate_type, box_type, strategy_type, bounds_tag> calculate_node_distance;
typedef typename calculate_value_distance::result_type value_distance_type;
typedef typename calculate_node_distance::result_type node_distance_type;
static const unsigned predicates_len = index::detail::predicates_length<Predicates>::value;
inline distance_query(parameters_type const& parameters, translator_type const& translator, Predicates const& pred, OutIter out_it)
: m_parameters(parameters), m_translator(translator)
, m_pred(pred)
, m_result(nearest_predicate_access::get(m_pred).count, out_it)
, m_strategy(index::detail::get_strategy(parameters))
{}
inline void operator()(internal_node const& n)
{
typedef typename rtree::elements_type<internal_node>::type elements_type;
// array of active nodes
typedef typename index::detail::rtree::container_from_elements_type<
elements_type,
std::pair<node_distance_type, typename allocators_type::node_pointer>
>::type active_branch_list_type;
active_branch_list_type active_branch_list;
active_branch_list.reserve(m_parameters.get_max_elements());
elements_type const& elements = rtree::elements(n);
// fill array of nodes meeting predicates
for (typename elements_type::const_iterator it = elements.begin();
it != elements.end(); ++it)
{
// if current node meets predicates
// 0 - dummy value
if ( index::detail::predicates_check
<
index::detail::bounds_tag, 0, predicates_len
>(m_pred, 0, it->first, m_strategy) )
{
// calculate node's distance(s) for distance predicate
node_distance_type node_distance;
// if distance isn't ok - move to the next node
if ( !calculate_node_distance::apply(predicate(), it->first,
m_strategy, node_distance) )
{
continue;
}
// if current node is further than found neighbors - don't analyze it
if ( m_result.has_enough_neighbors() &&
is_node_prunable(m_result.greatest_comparable_distance(), node_distance) )
{
continue;
}
// add current node's data into the list
active_branch_list.push_back( std::make_pair(node_distance, it->second) );
}
}
// if there aren't any nodes in ABL - return
if ( active_branch_list.empty() )
return;
// sort array
std::sort(active_branch_list.begin(), active_branch_list.end(), abl_less);
// recursively visit nodes
for ( typename active_branch_list_type::const_iterator it = active_branch_list.begin();
it != active_branch_list.end() ; ++it )
{
// if current node is further than furthest neighbor, the rest of nodes also will be further
if ( m_result.has_enough_neighbors() &&
is_node_prunable(m_result.greatest_comparable_distance(), it->first) )
break;
rtree::apply_visitor(*this, *(it->second));
}
// ALTERNATIVE VERSION - use heap instead of sorted container
// It seems to be faster for greater MaxElements and slower otherwise
// CONSIDER: using one global container/heap for active branches
// instead of a sorted container per level
// This would also change the way how branches are traversed!
// The same may be applied to the iterative version which btw suffers
// from the copying of the whole containers on resize of the ABLs container
//// make a heap
//std::make_heap(active_branch_list.begin(), active_branch_list.end(), abl_greater);
//// recursively visit nodes
//while ( !active_branch_list.empty() )
//{
// //if current node is further than furthest neighbor, the rest of nodes also will be further
// if ( m_result.has_enough_neighbors()
// && is_node_prunable(m_result.greatest_comparable_distance(), active_branch_list.front().first) )
// {
// break;
// }
// rtree::apply_visitor(*this, *(active_branch_list.front().second));
// std::pop_heap(active_branch_list.begin(), active_branch_list.end(), abl_greater);
// active_branch_list.pop_back();
//}
}
inline void operator()(leaf const& n)
{
typedef typename rtree::elements_type<leaf>::type elements_type;
elements_type const& elements = rtree::elements(n);
// search leaf for closest value meeting predicates
for (typename elements_type::const_iterator it = elements.begin();
it != elements.end(); ++it)
{
// if value meets predicates
if ( index::detail::predicates_check
<
index::detail::value_tag, 0, predicates_len
>(m_pred, *it, m_translator(*it), m_strategy) )
{
// calculate values distance for distance predicate
value_distance_type value_distance;
// if distance is ok
if ( calculate_value_distance::apply(predicate(), m_translator(*it),
m_strategy, value_distance) )
{
// store value
m_result.store(*it, value_distance);
}
}
}
}
inline size_t finish()
{
return m_result.finish();
}
private:
static inline bool abl_less(
std::pair<node_distance_type, typename allocators_type::node_pointer> const& p1,
std::pair<node_distance_type, typename allocators_type::node_pointer> const& p2)
{
return p1.first < p2.first;
}
//static inline bool abl_greater(
// std::pair<node_distance_type, typename allocators_type::node_pointer> const& p1,
// std::pair<node_distance_type, typename allocators_type::node_pointer> const& p2)
//{
// return p1.first > p2.first;
//}
template <typename Distance>
static inline bool is_node_prunable(Distance const& greatest_dist, node_distance_type const& d)
{
return greatest_dist <= d;
}
nearest_predicate_type const& predicate() const
{
return nearest_predicate_access::get(m_pred);
}
parameters_type const& m_parameters;
translator_type const& m_translator;
Predicates m_pred;
distance_query_result<value_type, translator_type, value_distance_type, OutIter> m_result;
strategy_type m_strategy;
};
template <
typename MembersHolder,
typename Predicates,
unsigned DistancePredicateIndex
>
class distance_query_incremental
: public MembersHolder::visitor_const
{
public:
typedef typename MembersHolder::value_type value_type;
typedef typename MembersHolder::box_type box_type;
typedef typename MembersHolder::parameters_type parameters_type;
typedef typename MembersHolder::translator_type translator_type;
typedef typename MembersHolder::allocators_type allocators_type;
typedef typename index::detail::strategy_type<parameters_type>::type strategy_type;
typedef typename MembersHolder::node node;
typedef typename MembersHolder::internal_node internal_node;
typedef typename MembersHolder::leaf leaf;
typedef index::detail::predicates_element<DistancePredicateIndex, Predicates> nearest_predicate_access;
typedef typename nearest_predicate_access::type nearest_predicate_type;
typedef typename indexable_type<translator_type>::type indexable_type;
typedef index::detail::calculate_distance<nearest_predicate_type, indexable_type, strategy_type, value_tag> calculate_value_distance;
typedef index::detail::calculate_distance<nearest_predicate_type, box_type, strategy_type, bounds_tag> calculate_node_distance;
typedef typename calculate_value_distance::result_type value_distance_type;
typedef typename calculate_node_distance::result_type node_distance_type;
typedef typename allocators_type::size_type size_type;
typedef typename allocators_type::const_reference const_reference;
typedef typename allocators_type::node_pointer node_pointer;
static const unsigned predicates_len = index::detail::predicates_length<Predicates>::value;
typedef typename rtree::elements_type<internal_node>::type internal_elements;
typedef typename internal_elements::const_iterator internal_iterator;
typedef typename rtree::elements_type<leaf>::type leaf_elements;
typedef std::pair<node_distance_type, node_pointer> branch_data;
typedef typename index::detail::rtree::container_from_elements_type<
internal_elements, branch_data
>::type active_branch_list_type;
struct internal_stack_element
{
internal_stack_element() : current_branch(0) {}
#ifdef BOOST_NO_CXX11_RVALUE_REFERENCES
// Required in c++03 for containers using Boost.Move
internal_stack_element & operator=(internal_stack_element const& o)
{
branches = o.branches;
current_branch = o.current_branch;
return *this;
}
#endif
active_branch_list_type branches;
typename active_branch_list_type::size_type current_branch;
};
typedef std::vector<internal_stack_element> internal_stack_type;
inline distance_query_incremental()
: m_translator(NULL)
// , m_pred()
, current_neighbor((std::numeric_limits<size_type>::max)())
// , next_closest_node_distance((std::numeric_limits<node_distance_type>::max)())
// , m_strategy_type()
{}
inline distance_query_incremental(parameters_type const& params, translator_type const& translator, Predicates const& pred)
: m_translator(::boost::addressof(translator))
, m_pred(pred)
, current_neighbor((std::numeric_limits<size_type>::max)())
, next_closest_node_distance((std::numeric_limits<node_distance_type>::max)())
, m_strategy(index::detail::get_strategy(params))
{
BOOST_GEOMETRY_INDEX_ASSERT(0 < max_count(), "k must be greather than 0");
}
const_reference dereference() const
{
return *(neighbors[current_neighbor].second);
}
void initialize(node_pointer root)
{
rtree::apply_visitor(*this, *root);
increment();
}
void increment()
{
for (;;)
{
size_type new_neighbor = current_neighbor == (std::numeric_limits<size_type>::max)() ? 0 : current_neighbor + 1;
if ( internal_stack.empty() )
{
if ( new_neighbor < neighbors.size() )
current_neighbor = new_neighbor;
else
{
current_neighbor = (std::numeric_limits<size_type>::max)();
// clear() is used to disable the condition above
neighbors.clear();
}
return;
}
else
{
active_branch_list_type & branches = internal_stack.back().branches;
typename active_branch_list_type::size_type & current_branch = internal_stack.back().current_branch;
if ( branches.size() <= current_branch )
{
internal_stack.pop_back();
continue;
}
// if there are no nodes which can have closer values, set new value
if ( new_neighbor < neighbors.size() &&
// here must be < because otherwise neighbours may be sorted in different order
// if there is another value with equal distance
neighbors[new_neighbor].first < next_closest_node_distance )
{
current_neighbor = new_neighbor;
return;
}
// if node is further than the furthest neighbour, following nodes also will be further
BOOST_GEOMETRY_INDEX_ASSERT(neighbors.size() <= max_count(), "unexpected neighbours count");
if ( max_count() <= neighbors.size() &&
is_node_prunable(neighbors.back().first, branches[current_branch].first) )
{
// stop traversing current level
internal_stack.pop_back();
continue;
}
else
{
// new level - must increment current_branch before traversing of another level (mem reallocation)
++current_branch;
rtree::apply_visitor(*this, *(branches[current_branch - 1].second));
next_closest_node_distance = calc_closest_node_distance(internal_stack.begin(), internal_stack.end());
}
}
}
}
bool is_end() const
{
return (std::numeric_limits<size_type>::max)() == current_neighbor;
}
friend bool operator==(distance_query_incremental const& l, distance_query_incremental const& r)
{
BOOST_GEOMETRY_INDEX_ASSERT(l.current_neighbor != r.current_neighbor ||
(std::numeric_limits<size_type>::max)() == l.current_neighbor ||
(std::numeric_limits<size_type>::max)() == r.current_neighbor ||
l.neighbors[l.current_neighbor].second == r.neighbors[r.current_neighbor].second,
"not corresponding iterators");
return l.current_neighbor == r.current_neighbor;
}
// Put node's elements into the list of active branches if those elements meets predicates
// and distance predicates(currently not used)
// and aren't further than found neighbours (if there is enough neighbours)
inline void operator()(internal_node const& n)
{
typedef typename rtree::elements_type<internal_node>::type elements_type;
elements_type const& elements = rtree::elements(n);
// add new element
internal_stack.resize(internal_stack.size()+1);
// fill active branch list array of nodes meeting predicates
for ( typename elements_type::const_iterator it = elements.begin() ; it != elements.end() ; ++it )
{
// if current node meets predicates
// 0 - dummy value
if ( index::detail::predicates_check
<
index::detail::bounds_tag, 0, predicates_len
>(m_pred, 0, it->first, m_strategy) )
{
// calculate node's distance(s) for distance predicate
node_distance_type node_distance;
// if distance isn't ok - move to the next node
if ( !calculate_node_distance::apply(predicate(), it->first,
m_strategy, node_distance) )
{
continue;
}
// if current node is further than found neighbors - don't analyze it
if ( max_count() <= neighbors.size() &&
is_node_prunable(neighbors.back().first, node_distance) )
{
continue;
}
// add current node's data into the list
internal_stack.back().branches.push_back( std::make_pair(node_distance, it->second) );
}
}
if ( internal_stack.back().branches.empty() )
internal_stack.pop_back();
else
// sort array
std::sort(internal_stack.back().branches.begin(), internal_stack.back().branches.end(), abl_less);
}
// Put values into the list of neighbours if those values meets predicates
// and distance predicates(currently not used)
// and aren't further than already found neighbours (if there is enough neighbours)
inline void operator()(leaf const& n)
{
typedef typename rtree::elements_type<leaf>::type elements_type;
elements_type const& elements = rtree::elements(n);
// store distance to the furthest neighbour
bool not_enough_neighbors = neighbors.size() < max_count();
value_distance_type greatest_distance = !not_enough_neighbors ? neighbors.back().first : (std::numeric_limits<value_distance_type>::max)();
// search leaf for closest value meeting predicates
for ( typename elements_type::const_iterator it = elements.begin() ; it != elements.end() ; ++it)
{
// if value meets predicates
if ( index::detail::predicates_check
<
index::detail::value_tag, 0, predicates_len
>(m_pred, *it, (*m_translator)(*it), m_strategy) )
{
// calculate values distance for distance predicate
value_distance_type value_distance;
// if distance is ok
if ( calculate_value_distance::apply(predicate(), (*m_translator)(*it),
m_strategy, value_distance) )
{
// if there is not enough values or current value is closer than furthest neighbour
if ( not_enough_neighbors || value_distance < greatest_distance )
{
neighbors.push_back(std::make_pair(value_distance, boost::addressof(*it)));
}
}
}
}
// sort array
std::sort(neighbors.begin(), neighbors.end(), neighbors_less);
// remove furthest values
if ( max_count() < neighbors.size() )
neighbors.resize(max_count());
}
private:
static inline bool abl_less(std::pair<node_distance_type, node_pointer> const& p1,
std::pair<node_distance_type, node_pointer> const& p2)
{
return p1.first < p2.first;
}
static inline bool neighbors_less(std::pair<value_distance_type, const value_type *> const& p1,
std::pair<value_distance_type, const value_type *> const& p2)
{
return p1.first < p2.first;
}
node_distance_type
calc_closest_node_distance(typename internal_stack_type::const_iterator first,
typename internal_stack_type::const_iterator last)
{
node_distance_type result = (std::numeric_limits<node_distance_type>::max)();
for ( ; first != last ; ++first )
{
if ( first->branches.size() <= first->current_branch )
continue;
node_distance_type curr_dist = first->branches[first->current_branch].first;
if ( curr_dist < result )
result = curr_dist;
}
return result;
}
template <typename Distance>
static inline bool is_node_prunable(Distance const& greatest_dist, node_distance_type const& d)
{
return greatest_dist <= d;
}
inline unsigned max_count() const
{
return nearest_predicate_access::get(m_pred).count;
}
nearest_predicate_type const& predicate() const
{
return nearest_predicate_access::get(m_pred);
}
const translator_type * m_translator;
Predicates m_pred;
internal_stack_type internal_stack;
std::vector< std::pair<value_distance_type, const value_type *> > neighbors;
size_type current_neighbor;
node_distance_type next_closest_node_distance;
strategy_type m_strategy;
};
}}} // namespace detail::rtree::visitors
}}} // namespace boost::geometry::index
#endif // BOOST_GEOMETRY_INDEX_DETAIL_RTREE_VISITORS_DISTANCE_QUERY_HPP
Zerion Mini Shell 1.0