#include <array2d.h>

Public Types
typedef T	value_type

Public Member Functions
	array2d ()

	array2d (int m, int n)

	array2d (int m, int n, T *a)

	array2d (int m, int n, const T &a)

	array2d (const array2d &A)

array2d &	operator= (const T &a)

array2d &	operator= (const array2d &A)

array2d &	ref (const array2d &A)

array2d	copy () const

array2d &	inject (const array2d &A)

T *	operator[] (int i)

const T *	operator[] (int i) const

int	dim1 () const

int	dim2 () const

int	ref_count () const

	~array2d ()

int	cols () const

int	rows () const

array2d< T > &	newsize (int m, int n)

array2d< T > &	set_size (int m, int n)

Detailed Description

template<class T>
class SPUC::array2d< T >

Templated two-dimensional, numerical array which looks like a conventional C multiarray. Storage corresponds to C (row-major) ordering. Elements are accessed via A[i][j] notation.

Array assignment is by reference (i.e. shallow assignment). That is, B=A implies that the A and B point to the same array, so modifications to the elements of A will be reflected in B. If an independent copy is required, then B = A.copy() can be used. Note that this facilitates returning arrays from functions without relying on compiler optimizations to eliminate extensive data copying.

The indexing and layout of this array object makes it compatible with C and C++ algorithms that utilize the familiar C[i][j] notation. This includes numerous textbooks, such as Numercial Recipes, and various public domain codes.

This class employs its own garbage collection via the use of reference counts. That is, whenever an internal array storage no longer has any references to it, it is destoryed.

Member Typedef Documentation

template<class T>

typedef T SPUC::array2d< T >::value_type

Constructor & Destructor Documentation

template<class T >

SPUC::array2d< T >::array2d ( )

Create a null (0x0) array.

template<class T >

SPUC::array2d< T >::array2d	(	int	m,
		int	n
	)

Create a new (m x n) array, WIHOUT initializing array elements. To create an initialized array of constants, see array2d(m,n,value).

This version avoids the O(m*n) initialization overhead and is used just before manual assignment.

Parameters

m	the first (row) dimension of the new matrix.
n	the second (column) dimension of the new matrix.

template<class T >

SPUC::array2d< T >::array2d	(	int	m,
		int	n,
		T *	a
	)

Create a new (m x n) array, as a view of an existing one-dimensional array stored in C order, i.e. right-most dimension varying fastest. (Often referred to as "row-major" ordering.) Note that the storage for this pre-existing array will never be garbage collected by the array2d class.

Parameters

m	the first (row) dimension of the new matrix.
n	the second (column) dimension of the new matrix.
a	the one dimensional C array to use as data storage for the array.

template<class T >

SPUC::array2d< T >::array2d	(	int	m,
		int	n,
		const T &	val
	)

Create a new (m x n) array, initializing array elements to constant specified by argument. Most often used to create an array of zeros, as in A(m, n, 0.0).

Parameters

m	the first (row) dimension of the new matrix.
n	the second (column) dimension of the new matrix.
val	the constant value to set all elements of the new array to.

template<class T >

SPUC::array2d< T >::array2d ( const array2d< T > & A )

inline

Copy constructor. Array data is NOT copied, but shared. Thus, in array2d B(A), subsequent changes to A will be reflected in B. For an indepent copy of A, use array2d B(A.copy()), or B = A.copy(), instead.

template<class T >

SPUC::array2d< T >::~array2d ( )

Member Function Documentation

template<class T >

int SPUC::array2d< T >::cols ( ) const

inline

template<class T >

array2d< T > SPUC::array2d< T >::copy ( ) const

Create a new of existing matrix. Used in B = A.copy() or in the construction of B, e.g. array2d B(A.copy()), to create a new array that does not share data.

template<class T >

int SPUC::array2d< T >::dim1 ( ) const

inline

Returns: the size of the first dimension of the array, i.e. the number of rows.

Referenced by SPUC::array2d< T >::set_size().

template<class T >

int SPUC::array2d< T >::dim2 ( ) const

inline

Returns: the size of the second dimension of the array, i.e. the number of columns.

Referenced by SPUC::array2d< T >::set_size().

template<class T >

array2d< T > & SPUC::array2d< T >::inject ( const array2d< T > & A )

Copy the elements to from one array to another, in place. That is B.inject(A), both A and B must conform (i.e. have identical row and column dimensions).

This differs from B = A.copy() in that references to B before this assignment are also affected. That is, if we have

        array2d A(m,n);
        array2d C(m,n);
        array2d B(C);        // elements of B and C are shared.

then B.inject(A) affects both and C, while B=A.copy() creates a new array B which shares no data with C or A.

Parameters

A	the array from elements will be copied

Returns: an instance of the modifed array. That is, in B.inject(A), it returns B. If A and B are not conformat, no modifications to B are made.

template<class T>

array2d<T>& SPUC::array2d< T >::newsize	(	int	m,
		int	n
	)

inline

References SPUC::array2d< T >::set_size().

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template<class T >

array2d< T > & SPUC::array2d< T >::operator= ( const T & a )

inline

Assign all elemnts of A to a constant scalar.

template<class T >

array2d< T > & SPUC::array2d< T >::operator= ( const array2d< T > & A )

inline

B = A is shorthand notation for B.ref(A).

template<class T >

T * SPUC::array2d< T >::operator[] ( int i )

inline

Used for A[i][j] indexing. The first [] operator returns a conventional pointer which can be dereferenced using the same [] notation.

If TNT_BOUNDS_CHECK macro is define, the left-most index (row index) is checked that it falls within the array bounds (via the assert() macro.) Note that bounds checking can occur in the row dimension, but the not column, since this is just a C pointer.

template<class T >

const T * SPUC::array2d< T >::operator[] ( int i ) const

inline

template<class T >

array2d< T > & SPUC::array2d< T >::ref ( const array2d< T > & A )

inline

Create a reference (shallow assignment) to another existing array. In B.ref(A), B and A shared the same data and subsequent changes to the array elements of one will be reflected in the other.

This is what operator= calls, and B=A and B.ref(A) are equivalent operations.