lshkit::TopkScanner< ACCESSOR, METRIC > Class Template Reference

Top-K scanner. More...

#include <topk.h>

List of all members.

Public Types
typedef ACCESSOR::Key	Key
	Key type.
typedef ACCESSOR::Value	Value
	Value type.
Public Member Functions
	TopkScanner (const ACCESSOR &accessor, const METRIC &metric, unsigned K, float R=std::numeric_limits< float >::max())
	Constructor.
void	reset (Value query)
	Reset the query.
unsigned	cnt () const
	Number of points scanned for the current query.
const Topk< Key > &	topk () const
	TopK results.
void	operator() (Key key)
	Update the current query by scanning key.

---

Detailed Description

template<typename ACCESSOR, typename METRIC>
class lshkit::TopkScanner< ACCESSOR, METRIC >

Top-K scanner.

Scans keys for top-K query. This is the object passed into the LSH query interface.

---

Constructor & Destructor Documentation

template<typename ACCESSOR, typename METRIC>

lshkit::TopkScanner< ACCESSOR, METRIC >::TopkScanner	(	const ACCESSOR &	accessor,
		const METRIC &	metric,
		unsigned	K,
		float	R = std::numeric_limits<float>::max()
	)			[inline]

Constructor.

Parameters:

	accessor	The scanner use accessor to retrieva values from keys.
	metric	The distance metric.
	K	value used to reset internal Topk class.
	R	value used to reset internal Topk class.

(ACCESSOR)accessor is used as a function. Given a key, accessor(key) returns an object (or reference) of the type LSH::Domain. That object is used to calculate a hash value. The key is saved in the hash table. When the associated object is needed, e.g. when scanning a bin, accessor(key) is called to access the object.

Metric metric is also used as a function. It accepts two parameters of the type LSH::Domain and returns the distance between the two.

---

Member Function Documentation

template<typename ACCESSOR, typename METRIC>

void lshkit::TopkScanner< ACCESSOR, METRIC >::operator()

(

Key

key

)

[inline]

Update the current query by scanning key.

This is normally invoked by the LSH index structure.

template<typename ACCESSOR, typename METRIC>

void lshkit::TopkScanner< ACCESSOR, METRIC >::reset

(

Value

query

)

[inline]

Reset the query.

This function should be invoked before each query.

---

The documentation for this class was generated from the following file:

• include/lshkit/topk.h

---