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k-nearest query optimized by use of heap instead of sorting.

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[SVN r74608]
This commit is contained in:
Adam Wulkiewicz
2011-09-29 11:48:13 +00:00
parent e6633533d6
commit 48176c64e6
2 changed files with 61 additions and 15 deletions
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37
include/boost/geometry/extensions/index/rtree/visitors/nearest.hpp
View File

@@ -73,22 +73,30 @@ public:
inline explicit nearest_k(size_t k)
: m_count(k)
{
// TEMP?
m_neighbors.reserve(m_count + 1);
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)
{
m_neighbors.push_back(std::make_pair(curr_comp_dist, val));
std::sort(m_neighbors.begin(), m_neighbors.end(), neighbors_less);
if ( m_neighbors.size() < m_count )
{
m_neighbors.push_back(std::make_pair(curr_comp_dist, val));
if ( m_count < m_neighbors.size() )
m_neighbors.pop_back();
// TODO: awulkiew - test other methods:
// heap, manual inserting
// don't sort if size < k ?
// check the furthest distance at the first place, before push_back()
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 is_comparable_distance_valid() const
@@ -98,9 +106,9 @@ public:
inline distance_type comparable_distance() const
{
return m_neighbors.size() < m_count ?
std::numeric_limits<distance_type>::max() :
m_neighbors.back().first;
return m_neighbors.size() < 0
? std::numeric_limits<distance_type>::max()
: m_neighbors.front().first;
}
template <typename OutIter>
@@ -123,6 +131,7 @@ private:
size_t m_count;
std::vector< std::pair<distance_type, Value> > m_neighbors;
distance_type m_biggest_comp_dist;
};
// TODO: awulkiew - add additional pruning before adding nodes to the ABL

39
tests/rtree_function.hpp
View File

@@ -148,6 +148,43 @@ namespace helpers
return true;
}
template <typename Point, typename Cont, typename Translator>
bool nearest_results_compare(Point const& p, Cont const& c1, Cont const& c2, Translator const& tr)
{
namespace bg = boost::geometry;
namespace bgi = boost::geometry::index;
typedef typename Translator::indexable_type indexable_type;
typedef bg::default_distance_result<Point, indexable_type>::type distance_type;
if ( c1.size() != c2.size() )
return false;
if ( c1.size() == 0 && c2.size() == 0 )
return true;
distance_type biggest_distance1 = 0;
for ( typename Cont::const_iterator it = c1.begin() ; it != c1.end() ; ++it )
{
distance_type curr_distance = bgi::comparable_distance_near(p, tr(*it));
if ( biggest_distance1 < curr_distance )
biggest_distance1 = curr_distance;
}
distance_type biggest_distance2 = 0;
for ( typename Cont::const_iterator it = c2.begin() ; it != c2.end() ; ++it )
{
distance_type curr_distance = bgi::comparable_distance_near(p, tr(*it));
if ( biggest_distance2 < curr_distance )
biggest_distance2 = curr_distance;
}
return biggest_distance1 == biggest_distance2;
}
template <typename Predicate, typename Rtree, typename Cont, typename Randomizer>
void random_query_check(Rtree const& t, Cont const& c, size_t n, Randomizer r)
{
@@ -233,7 +270,7 @@ namespace helpers
std::stringstream ss;
ss << "\nPredicate: " << typeid(Predicate).name() << "\nres1: " << res1.size() << ", res2: " << res2.size() << '\n';
BOOST_CHECK_MESSAGE( helpers::results_compare(res1, res2, t.get_translator()), ss.str());
BOOST_CHECK_MESSAGE(helpers::nearest_results_compare(pt, res1, res2, t.get_translator()), ss.str());
}
}
}