casacore::ImageExpr< T > Class Template Reference

Hold mathematical expressions involving ImageInterface objects. More...

#include <ImageExpr.h>

Inheritance diagram for casacore::ImageExpr< T >:

Public Member Functions
	ImageExpr ()
	The default constructor.
	ImageExpr (const LatticeExpr< T > &latticeExpr, const String &expr, const String &fileName=String())
	Construct an ImageExpr from a LatticeExpr.
	ImageExpr (const LatticeExpr< T > &latticeExpr, const String &expr, const String &fileName, const LELImageCoord &imCoord)
	Same as previous constructor, but the coordinates are taken from the given LELImageCoord object.
	ImageExpr (const ImageExpr< T > &other)
	Copy constructor (reference semantics).
	~ImageExpr ()
	Destructor does nothing.
ImageExpr< T > &	operator= (const ImageExpr< T > &other)
	Assignment (reference semantics).
virtual ImageInterface< T > *	cloneII () const
	Make a copy of the object (reference semantics).
virtual void	save (const String &fileName) const
	Save the image in an AipsIO file with the given name.
void	setFileName (const String &name)
	Set the file name.
virtual String	imageType () const
	Get the image type (returns name of derived class).
virtual Bool	isMasked () const
	Has the object really a mask?
virtual const LatticeRegion *	getRegionPtr () const
	Get the region used.
virtual IPosition	shape () const
	return the shape of the ImageExpr
virtual void	resize (const TiledShape &newShape)
	Function which changes the shape of the ImageExpr.
virtual Bool	doGetMaskSlice (Array< Bool > &buffer, const Slicer &section)
	Do the actual get of the mask data.
virtual Bool	doGetSlice (Array< T > &buffer, const Slicer &theSlice)
	Do the actual get of the data.
virtual void	doPutSlice (const Array< T > &sourceBuffer, const IPosition &where, const IPosition &stride)
	putSlice is not possible on an expression, so it throws an exception.
virtual String	name (Bool stripPath=False) const
	If the object is persistent, the file name is given.
virtual Bool	ok () const
	Check class invariants.
virtual LatticeIterInterface< T > *	makeIter (const LatticeNavigator &navigator, Bool useRef) const
	These are the implementations of the LatticeIterator letters.
virtual Bool	isWritable () const
	Returns False, as the ImageExpr is not writable.
virtual Bool	isPersistent () const
	Is the lattice persistent and can it be loaded by other processes as well?
virtual IPosition	doNiceCursorShape (uInt maxPixels) const
	Help the user pick a cursor for most efficient access if they only want pixel values and don't care about the order or dimension of the cursor.
virtual Bool	lock (FileLocker::LockType, uInt nattempts)
	Handle the (un)locking and syncing.
virtual void	unlock ()
virtual Bool	hasLock (FileLocker::LockType) const
virtual void	resync ()
	Resynchronize the Lattice object with the lattice file.
virtual void	tempClose ()
	Temporarily close the lattice.
virtual void	reopen ()
	Explicitly reopen the temporarily closed lattice.
const LatticeExpr< T > &	expression () const
	Get the lattice expression.
Private Attributes
LatticeExpr< T >	latticeExpr_p
Unit	unit_p
String	exprString_p
String	fileName_p

Detailed Description

template<class T>
class casacore::ImageExpr< T >

Hold mathematical expressions involving ImageInterface objects.

Intended use:

Public interface

Review Status

Test programs:: tImageExpr

Prerequisite

Etymology

This class holds a LatticeExpr object but inherits from ImageInterface hence ImageExpr

Synopsis

An ImageExpr object holds a LatticeExpr object which can be used to evaluate mathematical expressions involving Lattices. ImageExpr exists so that direct manipulation of LatticeExpr objects by methods expecting an ImageInterface, rather than a Lattice can occur.

The ImageExpr object is constructed from a LatticeExpr object, but only if the latter has true Coordinates associated with it. The ImageExpr object is not writable, so the ImageExpr object functions like a read only ImageInterface.

Example

 PagedImage<Float> a("imageB");                // Open PagedImages
 PagedImage<Float> b("imageB");
 
 LatticeExprNode node(a+b);                    // Create ImageExpr
 LatticeExpr<Float> lExpr(node);
 ImageExpr<Float> iExpr(lExpr);
 
 LogOrigin or("imageImpl", "main()", WHERE);   // Create statistics object
 LogIO logger(or);
 ImageStatistics<Float> stats(iExpr, logger);
 Bool ok = stats.display();                              // Display statistics

The ImageExpr object is evaluated during the call to stats.dislay(). Previously, the expression tree has been constructed, but not evaluated.

Motivation

This enables one to evaluate expressions but not to have to write them out to an output image.

Definition at line 110 of file ImageExpr.h.

Constructor & Destructor Documentation

template<class T>

casacore::ImageExpr< T >::ImageExpr ( )

The default constructor.

template<class T>

casacore::ImageExpr< T >::ImageExpr	(	const LatticeExpr< T > &	latticeExpr,
		const String &	expr,
		const String &	fileName = `String()`
	)

Construct an ImageExpr from a LatticeExpr.

The expr given should be the original expression string. The fileName argument is meant for ImageOpener. The coordinates are taken from the expression, usually the first image. An exception is thrown if the expression has no coordinates.

template<class T>

casacore::ImageExpr< T >::ImageExpr	(	const LatticeExpr< T > &	latticeExpr,
		const String &	expr,
		const String &	fileName,
		const LELImageCoord &	imCoord
	)

Same as previous constructor, but the coordinates are taken from the given LELImageCoord object.

template<class T>

casacore::ImageExpr< T >::ImageExpr ( const ImageExpr< T > & other )

Copy constructor (reference semantics).

template<class T>

casacore::ImageExpr< T >::~ImageExpr ( )

Destructor does nothing.

Member Function Documentation

template<class T>

virtual ImageInterface<T>* casacore::ImageExpr< T >::cloneII ( ) const [virtual]

Make a copy of the object (reference semantics).

Implements casacore::ImageInterface< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::doGetMaskSlice	(	Array< Bool > &	buffer,
		const Slicer &	section
	)			`[virtual]`

Do the actual get of the mask data.

The return value is always False, thus the buffer does not reference another array.

Reimplemented from casacore::MaskedLattice< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::doGetSlice	(	Array< T > &	buffer,
		const Slicer &	theSlice
	)			`[virtual]`

Do the actual get of the data.

Implements casacore::Lattice< T >.

template<class T>

virtual IPosition casacore::ImageExpr< T >::doNiceCursorShape ( uInt maxPixels ) const [virtual]

Help the user pick a cursor for most efficient access if they only want pixel values and don't care about the order or dimension of the cursor.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual void casacore::ImageExpr< T >::doPutSlice	(	const Array< T > &	sourceBuffer,
		const IPosition &	where,
		const IPosition &	stride
	)			`[virtual]`

putSlice is not possible on an expression, so it throws an exception.

Implements casacore::Lattice< T >.

template<class T>

const LatticeExpr<T>& casacore::ImageExpr< T >::expression ( ) const [inline]

Get the lattice expression.

Definition at line 214 of file ImageExpr.h.

template<class T>

virtual const LatticeRegion* casacore::ImageExpr< T >::getRegionPtr ( ) const [virtual]

Get the region used.

Implements casacore::MaskedLattice< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::hasLock ( FileLocker::LockType ) const [virtual]

Reimplemented from casacore::LatticeBase.

template<class T>

virtual String casacore::ImageExpr< T >::imageType ( ) const [virtual]

Get the image type (returns name of derived class).

Implements casacore::ImageInterface< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::isMasked ( ) const [virtual]

Has the object really a mask?

Reimplemented from casacore::MaskedLattice< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::isPersistent ( ) const [virtual]

Is the lattice persistent and can it be loaded by other processes as well?

Reimplemented from casacore::LatticeBase.

template<class T>

virtual Bool casacore::ImageExpr< T >::isWritable ( ) const [virtual]

Returns False, as the ImageExpr is not writable.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual Bool casacore::ImageExpr< T >::lock	(	FileLocker::LockType	,
		uInt	nattempts
	)			`[virtual]`

Handle the (un)locking and syncing.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual LatticeIterInterface<T>* casacore::ImageExpr< T >::makeIter	(	const LatticeNavigator &	navigator,
		Bool	useRef
	)			const `[virtual]`

These are the implementations of the LatticeIterator letters.

Note: not for public use

Reimplemented from casacore::Lattice< T >.

template<class T>

virtual String casacore::ImageExpr< T >::name ( Bool stripPath = False ) const [virtual]

If the object is persistent, the file name is given.

Otherwise it returns the expression string given in the constructor.

Implements casacore::ImageInterface< T >.

template<class T>

virtual Bool casacore::ImageExpr< T >::ok ( ) const [virtual]

Check class invariants.

Implements casacore::ImageInterface< T >.

template<class T>

ImageExpr<T>& casacore::ImageExpr< T >::operator= ( const ImageExpr< T > & other )

Assignment (reference semantics).

Reimplemented from casacore::ImageInterface< T >.

template<class T>

virtual void casacore::ImageExpr< T >::reopen ( ) [virtual]

Explicitly reopen the temporarily closed lattice.

By default the function does not do anything at all.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual void casacore::ImageExpr< T >::resize ( const TiledShape & newShape ) [virtual]

Function which changes the shape of the ImageExpr.

Throws an exception as ImageExpr is not writable.

Implements casacore::ImageInterface< T >.

template<class T>

virtual void casacore::ImageExpr< T >::resync ( ) [virtual]

Resynchronize the Lattice object with the lattice file.

This function is only useful if no read-locking is used, ie. if the table lock option is UserNoReadLocking or AutoNoReadLocking. In that cases the table system does not acquire a read-lock, thus does not synchronize itself automatically.
By default the function does not do anything at all.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual void casacore::ImageExpr< T >::save ( const String & fileName ) const [virtual]