Iterate an IPosition through the shape of an Array. More...

#include <ArrayPosIter.h>

Inheritance diagram for casacore::ArrayPositionIterator:

Public Member Functions
	ArrayPositionIterator (const IPosition &shape, const IPosition &origin, size_t byDim)
	Define the shape and origin of the volume the cursor will step through. More...

	ArrayPositionIterator (const IPosition &shape, size_t byDim)

	ArrayPositionIterator (const IPosition &shape, const IPosition &axes, bool axesAreCursor=true)
	Step through an array using the given axes. More...

virtual	~ArrayPositionIterator ()

virtual void	reset ()
	Reset the cursor to the beginning of the volume. More...

void	origin ()

bool	atStart () const
	Returns true of the cursor is at the origin. More...

bool	pastEnd () const
	Returns true if the cursor has moved past the end of its volume. More...

const IPosition &	pos () const
	Return the position of the cursor. More...

IPosition	endPos () const
	Return the end position of the cursor. More...

virtual void	next ()
	Advance the cursor to its next position. More...

virtual void	set (const IPosition &cursorPos)
	Set the cursor to the given position. More...

size_t	ndim () const
	What is the dimensionality of the volume we are iterating through? More...

const IPosition &	iterAxes () const
	Return the iteration axes. More...

const IPosition &	cursorAxes () const
	Return the cursor axes. More...

virtual ArrayBase &	getArray ()
	Get the array in the cursor. More...

Protected Member Functions
size_t	nextStep ()
	Advance cursor to its next position and tell which dimension stepped. More...

size_t	dimIter () const
	What is the dimensionality of the "step" the cursor takes, i.e. More...

Private Member Functions
void	setup (size_t byDim)
	Setup the object for the constructor. More...

void	setup (const IPosition &axes, bool axesAreCursor)

Private Attributes
IPosition	Start

IPosition	Shape

IPosition	End

IPosition	Cursor

bool	atOrBeyondEnd

IPosition	cursAxes

IPosition	iterationAxes

Detailed Description

Iterate an IPosition through the shape of an Array.

Review Status

Reviewed By:: UNKNOWN
Date Reviewed:: before2004/08/25

Synopsis

ArrayPositionIterator manipulates an IPosition "cursor" through some volume defined by an origin and shape. This position can in turn be used to index into, or otherwise define a position in, an Array. Normally users won't use this class directly, rather they will use an ArrayIterator, VectorIterator or MatrixIterator object, which in turn uses this class. ArrayPositionIterator is also used in the implementation of Array.

template<class T> void verySlowArrayCopy(Array<T> &to, const Array<T> &from)
{
if (! to.conform(from)) {
// throw some error
}
ArrayPositionIterator toiter(to.shape(), to.origin(),0);
ArrayPositionIterator fromiter(from.shape(), from.origin(),0);
// If to.origin() == from.origin() we only need one iterator
// or we could offset positions by the difference in origins.
// The "0" means we are stepping by scalars.
while (! toiter.pastEnd()) {    // we know arrays conform
to(toiter.pos()) = fromiter(fromiter.pos());
toiter.next(); fromiter.next();
}
}

Iteration can be done by any combination of axes, but it can only be done for full axes.
The iteration step always "fills up" its dimensionality. E.g., if we are stepping through a cube by matrices, the matrix completely fills up the plane. Casacore class ArrayLattice in the lattices package can be used to iterate with partial volumes.

ArrayPositionIterator also serves as the base class of ArrayIterator. Function makeIterator in class ArrayBase can be used to make an ArrayIterator without having to know the template type. Function getArray in this class can be used to obtain the current contents of the cursor as an ArrayBase object.

Definition at line 86 of file ArrayPosIter.h.

Constructor & Destructor Documentation

casacore::ArrayPositionIterator::ArrayPositionIterator	(	const IPosition &	shape,
		const IPosition &	origin,
		size_t	byDim
	)

Define the shape and origin of the volume the cursor will step through.

Also define the dimensionality of the step. byDim==0 implies we are stepping by scalars (i.e. every element), byDim==1 implies that we are stepping by vector, ==2 by matrices, and so on. If uses the first byDim axes as the cursor volume and it steps through the remaining axes.

casacore::ArrayPositionIterator::ArrayPositionIterator	(	const IPosition &	shape,
		size_t	byDim
	)

casacore::ArrayPositionIterator::ArrayPositionIterator	(	const IPosition &	shape,
		const IPosition &	axes,
		bool	axesAreCursor = `true`
	)

Step through an array using the given axes.

The axes can be given in two ways:

axesAreCursor=true means that the axes form the cursor axes. The remaining axes will form the iteration axes. This is the default.
axesAreCursor=false means the opposite. In this case the iteration axes can be given in any order.

E.g. when using iteration axes 2,0 for an array with shape [5,3,7], each iteration step returns a cursor (containing the data of axis 1). During the iteration axis 2 will vary most rapidly (as it was given first).
E.g. for a shape of [3,4,5,6] and cursor axes [2,0], the cursor size is [3,5] (axes 0 and 2), while the iteration is done over axes 1 and 3 (1 the fastest varying one).

virtual casacore::ArrayPositionIterator::~ArrayPositionIterator ( )

inlinevirtual

Definition at line 122 of file ArrayPosIter.h.

Member Function Documentation

bool casacore::ArrayPositionIterator::atStart ( ) const

Returns true of the cursor is at the origin.

Referenced by casacore::ReadOnlyMatrixIterator< T >::atStart().

const IPosition& casacore::ArrayPositionIterator::cursorAxes ( ) const

inline

Return the cursor axes.

Definition at line 164 of file ArrayPosIter.h.

References cursAxes.

size_t casacore::ArrayPositionIterator::dimIter ( ) const

inlineprotected

What is the dimensionality of the "step" the cursor takes, i.e.

0 for scalars, 1 for vector,....

Definition at line 176 of file ArrayPosIter.h.

References cursAxes, and casacore::IPosition::nelements().

IPosition casacore::ArrayPositionIterator::endPos ( ) const

Return the end position of the cursor.

Referenced by casacore::ReadOnlyMatrixIterator< T >::endPos().

virtual ArrayBase& casacore::ArrayPositionIterator::getArray ( )

virtual

Get the array in the cursor.

This is only implemented in the derived ArrayIterator class. By default it throws an exception.

Reimplemented in casacore::ArrayIterator< T, Alloc >, and casacore::ArrayIterator< T, std::allocator< T > >.

const IPosition& casacore::ArrayPositionIterator::iterAxes ( ) const

inline

Return the iteration axes.

Definition at line 161 of file ArrayPosIter.h.

References iterationAxes.

size_t casacore::ArrayPositionIterator::ndim ( ) const

inline

What is the dimensionality of the volume we are iterating through?

Dimensionality of the array we are iterating through.

Definition at line 192 of file ArrayPosIter.h.

References casacore::IPosition::nelements(), and Start.

Referenced by casacore::ReadOnlyMatrixIterator< T >::ndim().

virtual void casacore::ArrayPositionIterator::next ( )

virtual

Advance the cursor to its next position.

Reimplemented in casacore::ArrayIterator< T, Alloc >, and casacore::ArrayIterator< T, std::allocator< T > >.

size_t casacore::ArrayPositionIterator::nextStep ( )

protected

Advance cursor to its next position and tell which dimension stepped.

void casacore::ArrayPositionIterator::origin ( )

inline

Definition at line 127 of file ArrayPosIter.h.

References reset().

Referenced by casacore::ReadOnlyMatrixIterator< T >::origin(), and casacore::ReadOnlyMatrixIterator< T >::reset().

bool casacore::ArrayPositionIterator::pastEnd ( ) const

inline

Returns true if the cursor has moved past the end of its volume.

We are at the "end" if we cannot advance any more.

Definition at line 198 of file ArrayPosIter.h.

References atOrBeyondEnd.

Referenced by casacore::ReadOnlyMatrixIterator< T >::pastEnd().

const IPosition& casacore::ArrayPositionIterator::pos ( ) const

inline

Return the position of the cursor.

This include all axes

Definition at line 139 of file ArrayPosIter.h.

References Cursor.

Referenced by casacore::ReadOnlyMatrixIterator< T >::pos().

virtual void casacore::ArrayPositionIterator::reset ( )

virtual

Reset the cursor to the beginning of the volume.

Reimplemented in casacore::ArrayIterator< T, Alloc >, and casacore::ArrayIterator< T, std::allocator< T > >.

Referenced by origin().

virtual void casacore::ArrayPositionIterator::set ( const IPosition & cursorPos )

virtual

Set the cursor to the given position.

The position can only contain the iteration axes or it can be the full position.
In the first case the position must to be given in the order of the iteration axes as given in the constructor. In the latter case the position must be given in natural order (as given by function pos and only the cursor axes are taken into account.

Reimplemented in casacore::ArrayIterator< T, Alloc >, and casacore::ArrayIterator< T, std::allocator< T > >.

void casacore::ArrayPositionIterator::setup ( size_t byDim )

private

Setup the object for the constructor.

void casacore::ArrayPositionIterator::setup	(	const IPosition &	axes,
		bool	axesAreCursor
	)

private

Member Data Documentation

bool casacore::ArrayPositionIterator::atOrBeyondEnd

private

Definition at line 187 of file ArrayPosIter.h.

Referenced by pastEnd().

IPosition casacore::ArrayPositionIterator::cursAxes

private

Definition at line 188 of file ArrayPosIter.h.

Referenced by cursorAxes(), and dimIter().

IPosition casacore::ArrayPositionIterator::Cursor

private

Definition at line 186 of file ArrayPosIter.h.

Referenced by pos().

IPosition casacore::ArrayPositionIterator::End

private

Definition at line 186 of file ArrayPosIter.h.

IPosition casacore::ArrayPositionIterator::iterationAxes

private

Definition at line 188 of file ArrayPosIter.h.

Referenced by iterAxes().

IPosition casacore::ArrayPositionIterator::Shape

private

Definition at line 186 of file ArrayPosIter.h.

IPosition casacore::ArrayPositionIterator::Start

private

Definition at line 186 of file ArrayPosIter.h.

Referenced by ndim().

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

casa/Arrays/ArrayPosIter.h

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Review Status

Synopsis

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation