Index into an array using the longest axis. More...

#include <ArraySampledFunctional.h>

Inheritance diagram for casa::ArraySampledFunctional< T >:

Public Member Functions
	ArraySampledFunctional ()
	These constructors copy the array that is passed to them.
	ArraySampledFunctional (const T &data)
	ArraySampledFunctional (ArraySampledFunctional< T > &other)
	The standard copy constructor and assignment operator.
ArraySampledFunctional< T > &	operator= (ArraySampledFunctional< T > &other)
virtual T	operator() (const uInt &index) const
	Define the functions for the SampledFunction interface.
virtual uInt	nelements () const
	Return the total size of the data set.
virtual	~ArraySampledFunctional ()
const T	operator() (const uInt &index)
	An alternate version of the sampling function which is more effecient because it does not need to create as many temporary objects or copy the Array data.
Private Attributes
T	theRefData
IPosition	theEnd
uInt	theLastAxis
uInt	theNelements

Detailed Description

template<class T>
class casa::ArraySampledFunctional< T >

Index into an array using the longest axis.

Intended use:

Public interface

Review Status

Reviewed By:: wyoung
Date Reviewed:: 1996/10/19
Test programs:: tSampledFunctional

Prerequisite

Etymology

A SampledFunctional is an interface that allows random access to a fixed size data set. An ArraySampledFunctional allows you to access slices of an an Array<T> object.

Synopsis

An ArraySampledFunctional allows an Array<T> object to be sliced up with each sample being one slice of the original Array. The slices are always the same size and the indexing is always done along the last non-degenerate dimension. For example a(4,3,20,1) is interpreted as a SampledFunctional with 20 elements, each one being a 4 by 3 matrix.

The Array that is passed to the constructor is copied by this class but because Arrays themselves use reference symantics, the actual data is not copied but referenced. This means that modifying the data in the original array will correspondingly modify the data accessed by this class.

Similarly the Array that is returned for each Slice is a reference to the actual data so that modifying this array really modifies the original data. This is not recommended as the operator() function is not supposed to be used to get a modifiable portion of the data.

Example

Constructing and using ArraySampledFunctionals

    Array<Float> a(IPosition(4,4,3,20,1)); // Create an array
    ... Fill the array any way you like ..\.
    ArraySampledFunctional<Array<Float> >fa(a);
    for(uInt i = 0; i < 20; i++)
     cout << "f(" << i << ") = " << fa(i) << endl;
    // Each 'slice' is a 4 by 3 Matrix

Motivation

I needed a SampledFunctional which could return Arrays of arbitrary (but fixed) size for each index. This could be done using a ScalarSampledFunctional<Array<T> > but is ineffecient as each element is stored as a separate Array. This class is a more efficient way to solve this problem.

Template Type Argument Requirements (T)

The template type MUST be an Array of some arbitrary type. This is because this class will return a slice of this Array. The Array template type cannot be subsumed into the class definition because the definition of the inherited operator() function means that the return type must be the template type

Thrown Exceptions

Exceptions are not thrown directly by this class.

To Do

Nothing I can think of.

Definition at line 109 of file ArraySampledFunctional.h.

Constructor & Destructor Documentation

template<class T>

casa::ArraySampledFunctional< T >::ArraySampledFunctional ( )

These constructors copy the array that is passed to them.

But because arrays use reference symantics the data is not copied. The default constructor is basically useless, as there is no way to add the data once the class has been constructed.

template<class T>

casa::ArraySampledFunctional< T >::ArraySampledFunctional ( const T & data )

template<class T>

casa::ArraySampledFunctional< T >::ArraySampledFunctional ( ArraySampledFunctional< T > & other )

The standard copy constructor and assignment operator.

template<class T>

virtual casa::ArraySampledFunctional< T >::~ArraySampledFunctional ( ) [virtual]

Member Function Documentation

template<class T>

virtual uInt casa::ArraySampledFunctional< T >::nelements ( ) const [virtual]

Return the total size of the data set.

Implements casa::SampledFunctional< T >.

template<class T>

const T casa::ArraySampledFunctional< T >::operator() ( const uInt & index )

An alternate version of the sampling function which is more effecient because it does not need to create as many temporary objects or copy the Array data.

template<class T>

virtual T casa::ArraySampledFunctional< T >::operator() ( const uInt & index ) const [virtual]