casacore
Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
casacore::LatticeCache< T > Class Template Reference
lattices package (libcasa_lattices) » Lattices_module

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#include <LatticeCache.h>

Public Member Functions

 LatticeCache (Lattice< T > &image, Int cacheSize, IPosition tileShape, Vector< Float > &tileOverlap, Bool additive)
 Constructor: cachesize in units of T. More...
 
 LatticeCache (const LatticeCache< T > &other)
 
LatticeCache< T > & operator= (const LatticeCache< T > &other)
 
virtual ~LatticeCache ()
 
Array< T > & tile (IPosition &cacheLoc, const IPosition &tileLoc, Bool discard=True)
 Return the tile for a given location. More...
 
Array< T > & tile (const IPosition &tileLoc, Bool discard=True)
 
const Array< T > & tile (const IPosition &tileLoc)
 const version is needed More...
 
IPosition & cacheLocation (IPosition &cacheLoc, const IPosition &tileLoc)
 Return the IPosition for the start of this tile. More...
 
virtual void showCacheStatistics (ostream &os)
 Show the statistics of cache access. More...
 
virtual void clearCacheStatistics ()
 Clear the statistics of cache access. More...
 
virtual void flush ()
 Flush contents. More...
 

Protected Member Functions

 LatticeCache ()
 
Int getFreeTile (Bool readonly)
 
void writeTile (Int tile)
 
void readTile (Int tile, Bool readonly)
 

Protected Attributes

Int numberTiles
 
IPosition tileShape
 
Vector< Int > tileShapeVec
 
Vector< Int > tileOffsetVec
 
Vector< Float > tileOverlap
 
Bool additive
 
Int cacheSize
 
Int cacheAccesses
 
Int cacheHits
 
Int cacheMisses
 
Int cacheReads
 
Int cacheWrites
 
Block< IPosition > tileLocs
 
Block< Int > tileSequence
 
Block< Array< T > > tileContents
 
Lattice< T > * image_p
 

Detailed Description

template<class T>
class casacore::LatticeCache< T >

a class for caching image access via tiles

Intended use:

Public interface

Prerequisite

Etymology

This class divides an image into Tiles that are stored in a Cache.

Synopsis

An image is divided into tiles of a specified shape. Access to the image pixels is via these tiles. A cache of active tiles is kept in memory up to a specified limit in memory allocation. Tiles are flushed to disk using a Least-Recently-Used Criterion.

The tile size specified is the maximum dimension. Near the edge, smaller tiles are returned if necessary.

The offset needed to get back to true pixels is also available.

The cache hit rate for a sufficient number of random accesses goes as the ratio of cache size to image size.

Tiles may be overlapped. If there is any overlap then the caller is responsible for dealing with the overlap. Normally one will only want overlapping windows for additive operations in which case the additive flag to the constructor should be used.

Example

Motivation

To aid in gridding

Definition at line 95 of file LatticeCache.h.

Constructor & Destructor Documentation

◆ LatticeCache() [1/3]

template<class T >
casacore::LatticeCache< T >::LatticeCache ( Lattice< T > &  image,
Int  cacheSize,
IPosition  tileShape,
Vector< Float > &  tileOverlap,
Bool  additive 
)

Constructor: cachesize in units of T.

tileOverlap is the fractional overlap between neighbouring tile.

◆ LatticeCache() [2/3]

template<class T >
casacore::LatticeCache< T >::LatticeCache ( const LatticeCache< T > &  other)

◆ ~LatticeCache()

template<class T >
virtual casacore::LatticeCache< T >::~LatticeCache ( )
virtual

◆ LatticeCache() [3/3]

template<class T >
casacore::LatticeCache< T >::LatticeCache ( )
inlineprotected

Definition at line 133 of file LatticeCache.h.

Member Function Documentation

◆ cacheLocation()

template<class T >
IPosition& casacore::LatticeCache< T >::cacheLocation ( IPosition &  cacheLoc,
const IPosition &  tileLoc 
)

Return the IPosition for the start of this tile.

◆ clearCacheStatistics()

template<class T >
virtual void casacore::LatticeCache< T >::clearCacheStatistics ( )
virtual

Clear the statistics of cache access.

◆ flush()

template<class T >
virtual void casacore::LatticeCache< T >::flush ( )
virtual

Flush contents.

◆ getFreeTile()

template<class T >
Int casacore::LatticeCache< T >::getFreeTile ( Bool  readonly)
protected

◆ operator=()

template<class T >
LatticeCache<T>& casacore::LatticeCache< T >::operator= ( const LatticeCache< T > &  other)

◆ readTile()

template<class T >
void casacore::LatticeCache< T >::readTile ( Int  tile,
Bool  readonly 
)
protected

◆ showCacheStatistics()

template<class T >
virtual void casacore::LatticeCache< T >::showCacheStatistics ( ostream &  os)
virtual

Show the statistics of cache access.

◆ tile() [1/3]

template<class T >
const Array<T>& casacore::LatticeCache< T >::tile ( const IPosition &  tileLoc)

const version is needed

◆ tile() [2/3]

template<class T >
Array<T>& casacore::LatticeCache< T >::tile ( const IPosition &  tileLoc,
Bool  discard = True 
)

◆ tile() [3/3]

template<class T >
Array<T>& casacore::LatticeCache< T >::tile ( IPosition &  cacheLoc,
const IPosition &  tileLoc,
Bool  discard = True 
)

Return the tile for a given location.

◆ writeTile()

template<class T >
void casacore::LatticeCache< T >::writeTile ( Int  tile)
protected

Member Data Documentation

◆ additive

template<class T >
Bool casacore::LatticeCache< T >::additive
protected

Definition at line 139 of file LatticeCache.h.

◆ cacheAccesses

template<class T >
Int casacore::LatticeCache< T >::cacheAccesses
protected

Definition at line 142 of file LatticeCache.h.

◆ cacheHits

template<class T >
Int casacore::LatticeCache< T >::cacheHits
protected

Definition at line 143 of file LatticeCache.h.

◆ cacheMisses

template<class T >
Int casacore::LatticeCache< T >::cacheMisses
protected

Definition at line 144 of file LatticeCache.h.

◆ cacheReads

template<class T >
Int casacore::LatticeCache< T >::cacheReads
protected

Definition at line 145 of file LatticeCache.h.

◆ cacheSize

template<class T >
Int casacore::LatticeCache< T >::cacheSize
protected

Definition at line 141 of file LatticeCache.h.

◆ cacheWrites

template<class T >
Int casacore::LatticeCache< T >::cacheWrites
protected

Definition at line 146 of file LatticeCache.h.

◆ image_p

template<class T >
Lattice<T>* casacore::LatticeCache< T >::image_p
protected

Definition at line 157 of file LatticeCache.h.

◆ numberTiles

template<class T >
Int casacore::LatticeCache< T >::numberTiles
protected

Definition at line 135 of file LatticeCache.h.

◆ tileContents

template<class T >
Block<Array<T> > casacore::LatticeCache< T >::tileContents
protected

Definition at line 152 of file LatticeCache.h.

◆ tileLocs

template<class T >
Block<IPosition> casacore::LatticeCache< T >::tileLocs
protected

Definition at line 150 of file LatticeCache.h.

◆ tileOffsetVec

template<class T >
Vector<Int> casacore::LatticeCache< T >::tileOffsetVec
protected

Definition at line 137 of file LatticeCache.h.

◆ tileOverlap

template<class T >
Vector<Float> casacore::LatticeCache< T >::tileOverlap
protected

Definition at line 138 of file LatticeCache.h.

◆ tileSequence

template<class T >
Block<Int> casacore::LatticeCache< T >::tileSequence
protected

Definition at line 151 of file LatticeCache.h.

◆ tileShape

template<class T >
IPosition casacore::LatticeCache< T >::tileShape
protected

Definition at line 136 of file LatticeCache.h.

◆ tileShapeVec

template<class T >
Vector<Int> casacore::LatticeCache< T >::tileShapeVec
protected

Definition at line 137 of file LatticeCache.h.

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