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/*
*
* Template Numerical Toolkit (TNT)
*
* Mathematical and Computational Sciences Division
* National Institute of Technology,
* Gaithersburg, MD USA
*
*
* This software was developed at the National Institute of Standards and
* Technology (NIST) by employees of the Federal Government in the course
* of their official duties. Pursuant to title 17 Section 105 of the
* United States Code, this software is not subject to copyright protection
* and is in the public domain. NIST assumes no responsibility whatsoever for
* its use by other parties, and makes no guarantees, expressed or implied,
* about its quality, reliability, or any other characteristic.
*
*/
#ifndef TNT_ARRAY2D_H
#define TNT_ARRAY2D_H
#include <cstdlib>
#include <iostream>
#ifdef TNT_BOUNDS_CHECK
#include <assert.h>
#endif
#include "tnt_array1d.h"
namespace TNT
{
/**
Ttwo-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 for 0-based indexing,
and A(i,j) for 1-based indexing..
<p>
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.
<p>
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.
*/
template <class T>
class Array2D
{
private:
Array1D<T> data_;
Array1D<T*> v_;
int m_;
int n_;
public:
/**
Used to determined the data type of array entries. This is most
commonly used when requiring scalar temporaries in templated algorithms
that have TNT arrays as input. For example,
<pre>
template < class ArrayTwoD >
void foo(ArrayTwoD &A)
{
A::value_type first_entry = A[0][0];
...
}
</pre>
*/
typedef T value_type;
/**
Create a null array. This is <b>not</b> the same
as Array2D(0,0), which consumes some memory overhead.
*/
Array2D();
/**
Create a new (m x n) array, without initalizing elements. (This
encurs an O(1) operation cost, rather than a O(m*n) cost.)
@param m the first (row) dimension of the new matrix.
@param n the second (column) dimension of the new matrix.
*/
Array2D(int m, int n);
/**
Create a new (m x n) array, as a view of an existing one-dimensional
array stored in row-major order, i.e. right-most dimension varying fastest.
Note that the storage for this pre-existing array will
never be destroyed by TNT.
@param m the first (row) dimension of the new matrix.
@param n the second (column) dimension of the new matrix.
@param a the one dimensional C array to use as data storage for
the array.
*/
Array2D(int m, int n, T *a);
/**
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).
@param m the first (row) dimension of the new matrix.
@param n the second (column) dimension of the new matrix.
@param val the constant value to set all elements of the new array to.
*/
Array2D(int m, int n, const T &val);
/**
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.
*/
inline Array2D(const Array2D &A);
/**
Convert 2D array into a regular multidimensional C pointer. Most often
called automatically when calling C interfaces that expect things like
double** rather than Array2D<dobule>.
*/
inline operator T**();
/**
Convert a const 2D array into a const multidimensional C pointer.
Most often called automatically when calling C interfaces that expect
things like "const double**" rather than "const Array2D<dobule>&".
*/
inline operator const T**() const;
/**
Assign all elements of array the same value.
@param val the value to assign each element.
*/
inline Array2D & operator=(const T &val);
/**
Assign one Array2D to another. (This is a shallow-assignement operation,
and it is the identical semantics to ref(A).
@param A the array to assign this one to.
*/
inline Array2D & operator=(const Array2D &A);
inline Array2D & ref(const Array2D &A);
Array2D copy() const;
Array2D & inject(const Array2D & A);
inline T* operator[](int i);
inline const T* operator[](int i) const;
inline int dim1() const;
inline int dim2() const;
~Array2D();
/* extended interface (not part of the standard) */
inline int ref_count();
inline int ref_count_data();
inline int ref_count_dim1();
Array2D subarray(int i0, int i1, int j0, int j1);
};
/**
Create a new (m x n) array, WIHOUT initializing array elements.
To create an initialized array of constants, see Array2D(m,n,value).
<p>
This version avoids the O(m*n) initialization overhead and
is used just before manual assignment.
@param m the first (row) dimension of the new matrix.
@param n the second (column) dimension of the new matrix.
*/
template <class T>
Array2D<T>::Array2D() : data_(), v_(), m_(0), n_(0) {}
template <class T>
Array2D<T>::Array2D(const Array2D<T> &A) : data_(A.data_), v_(A.v_),
m_(A.m_), n_(A.n_) {}
template <class T>
Array2D<T>::Array2D(int m, int n) : data_(m*n), v_(m), m_(m), n_(n)
{
if (m>0 && n>0)
{
T* p = &(data_[0]);
for (int i=0; i<m; i++)
{
v_[i] = p;
p += n;
}
}
}
template <class T>
Array2D<T>::Array2D(int m, int n, const T &val) : data_(m*n), v_(m),
m_(m), n_(n)
{
if (m>0 && n>0)
{
data_ = val;
T* p = &(data_[0]);
for (int i=0; i<m; i++)
{
v_[i] = p;
p += n;
}
}
}
template <class T>
Array2D<T>::Array2D(int m, int n, T *a) : data_(m*n, a), v_(m), m_(m), n_(n)
{
if (m>0 && n>0)
{
T* p = &(data_[0]);
for (int i=0; i<m; i++)
{
v_[i] = p;
p += n;
}
}
}
template <class T>
inline T* Array2D<T>::operator[](int i)
{
#ifdef TNT_BOUNDS_CHECK
assert(i >= 0);
assert(i < m_);
#endif
return v_[i];
}
template <class T>
inline const T* Array2D<T>::operator[](int i) const
{
#ifdef TNT_BOUNDS_CHECK
assert(i >= 0);
assert(i < m_);
#endif
return v_[i];
}
template <class T>
Array2D<T> & Array2D<T>::operator=(const T &a)
{
/* non-optimzied, but will work with subarrays in future verions */
for (int i=0; i<m_; i++)
for (int j=0; j<n_; j++)
v_[i][j] = a;
return *this;
}
template <class T>
Array2D<T> Array2D<T>::copy() const
{
Array2D A(m_, n_);
for (int i=0; i<m_; i++)
for (int j=0; j<n_; j++)
A[i][j] = v_[i][j];
return A;
}
template <class T>
Array2D<T> & Array2D<T>::inject(const Array2D &A)
{
if (A.m_ == m_ && A.n_ == n_)
{
for (int i=0; i<m_; i++)
for (int j=0; j<n_; j++)
v_[i][j] = A[i][j];
}
return *this;
}
template <class T>
Array2D<T> & Array2D<T>::ref(const Array2D<T> &A)
{
if (this != &A)
{
v_ = A.v_;
data_ = A.data_;
m_ = A.m_;
n_ = A.n_;
}
return *this;
}
template <class T>
Array2D<T> & Array2D<T>::operator=(const Array2D<T> &A)
{
return ref(A);
}
template <class T>
inline int Array2D<T>::dim1() const { return m_; }
template <class T>
inline int Array2D<T>::dim2() const { return n_; }
template <class T>
Array2D<T>::~Array2D() {}
template <class T>
inline Array2D<T>::operator T**()
{
return &(v_[0]);
}
template <class T>
inline Array2D<T>::operator const T**() const
{
return static_cast<const T**>(&(v_[0]));
}
/* ............... extended interface ............... */
/**
Create a new view to a subarray defined by the boundaries
[i0][i0] and [i1][j1]. The size of the subarray is
(i1-i0) by (j1-j0). If either of these lengths are zero
or negative, the subarray view is null.
*/
template <class T>
Array2D<T> Array2D<T>::subarray(int i0, int i1, int j0, int j1)
{
Array2D<T> A;
int m = i1-i0+1;
int n = j1-j0+1;
/* if either length is zero or negative, this is an invalide
subarray. return a null view.
*/
if (m<1 || n<1)
return A;
A.data_ = data_;
A.m_ = m;
A.n_ = n;
A.v_ = Array1D<T*>(m);
T* p = &(data_[0]) + i0 * n_ + j0;
for (int i=0; i<m; i++)
{
A.v_[i] = p + i*n_;
}
return A;
}
template <class T>
inline int Array2D<T>::ref_count()
{
return ref_count_data();
}
template <class T>
inline int Array2D<T>::ref_count_data()
{
return data_.ref_count();
}
template <class T>
inline int Array2D<T>::ref_count_dim1()
{
return v_.ref_count();
}
} /* namespace TNT */
#endif
/* TNT_ARRAY2D_H */
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