casacore::ArrayLattice< T > Class Template Reference

#include <ArrayLattice.h>

Inheritance diagram for casacore::ArrayLattice< T >:

Public Member Functions
	ArrayLattice ()
	The default constructor creates a ArrayLattice that is useless for just about everything, except that it can be assigned to with the assignment operator.
	ArrayLattice (const IPosition &shape)
	Construct an ArrayLattice with the specified shape.
	ArrayLattice (Array< T > &array, Bool isWritable=True)
	Construct an ArrayLattice that references the given Array.
	ArrayLattice (const Array< T > &array)
	Construct an ArrayLattice that references the given Array.
	ArrayLattice (const ArrayLattice< T > &other)
	The copy constructor uses reference semantics.
virtual	~ArrayLattice ()
ArrayLattice< T > &	operator= (const ArrayLattice< T > &other)
	The assignment operator uses copy semantics.
virtual Lattice< T > *	clone () const
	Make a copy of the object (reference semantics).
virtual Bool	canReferenceArray () const
	The lattice data can be referenced as an array section.
virtual Bool	isWritable () const
	Is the lattice writable?
virtual IPosition	shape () const
	returns the shape of the ArrayLattice.
virtual void	set (const T &value)
	Set all of the elements in the Lattice to a value.
Array< T > &	asArray ()
	Return the Array of the data within this Lattice.
const Array< T > &	asArray () const
virtual T	getAt (const IPosition &where) const
	Return the value of the single element located at the argument IPosition.
virtual void	putAt (const T &value, const IPosition &where)
	Put the value of a single element.
virtual Bool	ok () const
	Check for internal consistency.
virtual uInt	advisedMaxPixels () const
	Returns the maximum recommended number of pixels for a cursor.
void	getIterSlice (Array< T > &buffer, const IPosition &start, const IPosition &end, const IPosition &incr)
	Get a slice in an optimized way (specifically for ArrLatticeIter).
Protected Member Functions
virtual Bool	doGetSlice (Array< T > &buffer, const Slicer &section)
	Do the actual getting of an array of values.
virtual void	doPutSlice (const Array< T > &sourceBuffer, const IPosition &where, const IPosition &stride)
	Do the actual putting of an array of values.
Private Attributes
Array< T >	itsData
Bool	itsWritable

Detailed Description

template<class T>
class casacore::ArrayLattice< T >

A memory resident Lattice.

Intended use:

Public interface

Review Status

Reviewed By:: Peter Barnes
Date Reviewed:: 1999/10/30
Test programs:: tArrayLattice

Prerequisite

Etymology

The ArrayLattice name reflects its role as a Lattice interface to an Array object.

Synopsis

An ArrayLattice is a concrete Lattice class where the data is stored in memory as opposed to the PagedArray class where the data is stored on disk. As a result this class is much more suitable to problems which require small Lattices that can fit into the memory of a computer.

ArrayLattice imposes another layer of function calls on top of a an Array. As a result they should not be used for generic Array manipulation. They are useful if you have an Array that needs to use Lattice functions or needs to be used with PagedArrays or other Lattice derivatives (like LatticeExpr or SubLattice ). For example the LatticeIterator class can iterate through an Array in more ways than any of the ArrayIterator classes can. The examples below illustrate some uses for ArrayLattices.

Example

All the examples in this section are available in dArrayLattice.cc

Example 1:

In this example an Array of data is converted into an ArrayLattice so that the copyData function can be used to write the data to a PagedArray which will be stored on disk.

 // make an Array and fill it with data.
 Array<Float> myArray(IPosition(3, 64, 64, 2));
 indgen(myArray); // fills the Array with 0,1,2,....,64*64*2-1
 // construct the ArrayLattice
 ArrayLattice<Float> myLattice(myArray);
 // make a PagedArray to store the data on disk
 PagedArray<Float> myPagedArray(myLattice.shape(), "myTestData.array");
 // now copy the data onto disk
 myPagedArray.copyData (myLattice);

Note that it could be done in a somewhat simpler way as:

 // make an Array and fill it with data.
 Array<Float> myArray(IPosition(3, 64, 64, 2));
 indgen(myArray); // fills the Array with 0,1,2,....,64*64*2-1
 // make a PagedArray to store the data on disk
 PagedArray<Float> myPagedArray(myLattice.shape(), "myTestData.array");
 // now put the data onto disk
 myPagedArray.put (myArray);

Example 2:

The ArrayIterator class (or its derivatives the VectorIterator and the MatrixIterator classes) do not allow the user to specify a cursor shape. In this example a Cube class will be converted into an ArrayLattice so that an ArrLatticeIter can be used to access the data spectrum by spectrum (assuming the z-axis is frequency).

 Cube<Float> arr(64,64,128);
 // assume that the data gets put into the cube somehow
 // now construct an ArrayLattice from this cube.
 ArrayLattice<Float> lat(arr);
 // Construct an iterator that returns the 128-element spectra one at a time
 ArrLatticeIter<Float> iter(lat, IPosition(3,1,1,128));
 // construct a Matrix to hold the results
 Matrix<Float> channelSum(64,64);
 // and do the summation one spectrum at a time
 for (iter.reset(); !iter.atEnd(); iter++)
 channelSum(iter.position().getFirst(2)) = sum(iter.cursor());

There are more examples in the Lattice class and many of the examples in the PagedArray class will also be instructive.

Motivation

We needed a way of creating Lattices but with Casacore Array characteristics.

Definition at line 146 of file ArrayLattice.h.

Constructor & Destructor Documentation

template<class T>

casacore::ArrayLattice< T >::ArrayLattice ( )

The default constructor creates a ArrayLattice that is useless for just about everything, except that it can be assigned to with the assignment operator.

template<class T>

casacore::ArrayLattice< T >::ArrayLattice ( const IPosition & shape ) [explicit]

Construct an ArrayLattice with the specified shape.

It results in a writable lattice.

template<class T>

casacore::ArrayLattice< T >::ArrayLattice	(	Array< T > &	array,
		Bool	isWritable = `True`
	)

Construct an ArrayLattice that references the given Array.

By default it results in a writable lattice.

template<class T>

casacore::ArrayLattice< T >::ArrayLattice ( const Array< T > & array )

Construct an ArrayLattice that references the given Array.

It results in a non-writable lattice.

template<class T>

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

The copy constructor uses reference semantics.

template<class T>

virtual casacore::ArrayLattice< T >::~ArrayLattice ( ) [virtual]

Member Function Documentation

template<class T>

virtual uInt casacore::ArrayLattice< T >::advisedMaxPixels ( ) const [virtual]

Returns the maximum recommended number of pixels for a cursor.

For this class this is equal to the number of pixels in the lattice.

Reimplemented from casacore::Lattice< T >.

template<class T>

const Array<T>& casacore::ArrayLattice< T >::asArray ( ) const

template<class T>

Array<T>& casacore::ArrayLattice< T >::asArray ( )

Return the Array of the data within this Lattice.

template<class T>

virtual Bool casacore::ArrayLattice< T >::canReferenceArray ( ) const [virtual]

The lattice data can be referenced as an array section.

Reimplemented from casacore::LatticeBase.

template<class T>

virtual Lattice<T>* casacore::ArrayLattice< T >::clone ( ) const [virtual]

Make a copy of the object (reference semantics).

Implements casacore::Lattice< T >.

template<class T>

virtual Bool casacore::ArrayLattice< T >::doGetSlice	(	Array< T > &	buffer,
		const Slicer &	section
	)			`[protected, virtual]`

Do the actual getting of an array of values.

Implements casacore::Lattice< T >.

template<class T>

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