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casacore::ArrayPositionIterator Class Reference

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

#include <ArrayPosIter.h>

Inheritance diagram for casacore::ArrayPositionIterator:
casacore::ArrayIterator< casacore::Bool > casacore::ArrayIterator< casacore::Double > casacore::ArrayIterator< T > casacore::MatrixIterator< T > casacore::VectorIterator< T >

Public Member Functions

 ArrayPositionIterator (const IPosition &shape, const IPosition &origin, uInt byDim)
 Define the shape and origin of the volume the cursor will step through. More...
 
 ArrayPositionIterator (const IPosition &shape, uInt 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 IPositionpos () 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...
 
uInt ndim () const
 What is the dimensionality of the volume we are iterating through? More...
 
const IPositioniterAxes () const
 Return the iteration axes. More...
 
const IPositioncursorAxes () const
 Return the cursor axes. More...
 
virtual ArrayBasegetArray ()
 Get the array in the cursor. More...
 

Protected Member Functions

uInt nextStep ()
 Advance cursor to its next position and tell which dimension stepped. More...
 
uInt dimIter () const
 What is the dimensionality of the "step" the cursor takes, i.e. More...
 

Private Member Functions

void setup (uInt 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. 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 87 of file ArrayPosIter.h.

Constructor & Destructor Documentation

casacore::ArrayPositionIterator::ArrayPositionIterator ( const IPosition shape,
const IPosition origin,
uInt  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,
uInt  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:

  1. axesAreCursor=True means that the axes form the cursor axes. The remaining axes will form the iteration axes. This is the default.
  2. 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 123 of file ArrayPosIter.h.

Member Function Documentation

Bool casacore::ArrayPositionIterator::atStart ( ) const

Returns true of the cursor is at the origin.

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

Return the cursor axes.

Definition at line 165 of file ArrayPosIter.h.

References cursAxes.

uInt 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 177 of file ArrayPosIter.h.

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

IPosition casacore::ArrayPositionIterator::endPos ( ) const

Return the end position of the cursor.

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 >, casacore::ArrayIterator< casacore::Double >, and casacore::ArrayIterator< casacore::Bool >.

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

Return the iteration axes.

Definition at line 162 of file ArrayPosIter.h.

References iterationAxes.

uInt 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 193 of file ArrayPosIter.h.

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

virtual void casacore::ArrayPositionIterator::next ( )
virtual
uInt casacore::ArrayPositionIterator::nextStep ( )
protected

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

void casacore::ArrayPositionIterator::origin ( )
inline

Definition at line 128 of file ArrayPosIter.h.

References 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 199 of file ArrayPosIter.h.

References atOrBeyondEnd.

Referenced by casa::CalStats::stats().

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

Return the position of the cursor.

This include all axes

Definition at line 140 of file ArrayPosIter.h.

References Cursor.

Referenced by casa::CalStats::stats().

virtual void casacore::ArrayPositionIterator::reset ( )
virtual

Reset the cursor to the beginning of the volume.

Reimplemented in casacore::ArrayIterator< T >, casacore::ArrayIterator< casacore::Double >, and casacore::ArrayIterator< casacore::Bool >.

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 >, casacore::ArrayIterator< casacore::Double >, and casacore::ArrayIterator< casacore::Bool >.

void casacore::ArrayPositionIterator::setup ( uInt  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 188 of file ArrayPosIter.h.

Referenced by pastEnd().

IPosition casacore::ArrayPositionIterator::cursAxes
private

Definition at line 189 of file ArrayPosIter.h.

Referenced by cursorAxes(), and dimIter().

IPosition casacore::ArrayPositionIterator::Cursor
private

Definition at line 187 of file ArrayPosIter.h.

Referenced by pos().

IPosition casacore::ArrayPositionIterator::End
private

Definition at line 187 of file ArrayPosIter.h.

IPosition casacore::ArrayPositionIterator::iterationAxes
private

Definition at line 189 of file ArrayPosIter.h.

Referenced by iterAxes().

IPosition casacore::ArrayPositionIterator::Shape
private

Definition at line 187 of file ArrayPosIter.h.

IPosition casacore::ArrayPositionIterator::Start
private

Definition at line 187 of file ArrayPosIter.h.

Referenced by ndim().


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