```// Copyright (C) 2006  Davis E. King (davis@dlib.net)
#undef DLIB_MATRIx_SUBEXP_ABSTRACT_
#ifdef DLIB_MATRIx_SUBEXP_ABSTRACT_

#include "matrix_abstract.h"
#include "../geometry/rectangle.h"

namespace dlib
{

// ----------------------------------------------------------------------------------------

template <long start, long inc, long end>
const matrix_exp range (
);
/*!
requires
- inc > 0
ensures
- returns a matrix R such that:
- R::type == long
- R.nr() == 1
- R.nc() == abs(end - start)/inc + 1
- if (start <= end) then
- R(i) == start + i*inc
- else
- R(i) == start - i*inc
!*/

template <long start, long end>
const matrix_exp range (
) { return range<start,1,end>(); }

const matrix_exp range (
long start,
long inc,
long end
);
/*!
requires
- inc > 0
ensures
- returns a matrix R such that:
- R::type == long
- R.nr() == 1
- R.nc() == abs(end - start)/inc + 1
- if (start <= end) then
- R(i) == start + i*inc
- else
- R(i) == start - i*inc
!*/

const matrix_exp range (
long start,
long end
) { return range(start,1,end); }

// ----------------------------------------------------------------------------------------

const matrix_exp subm (
const matrix_exp& m,
const matrix_exp& rows,
const matrix_exp& cols,
);
/*!
requires
- rows and cols contain integral elements (e.g. int, long)
- 0 <= min(rows) && max(rows) < m.nr()
- 0 <= min(cols) && max(cols) < m.nc()
- rows.nr() == 1 || rows.nc() == 1
- cols.nr() == 1 || cols.nc() == 1
(i.e. rows and cols must be vectors)
ensures
- returns a matrix R such that:
- R::type == the same type that was in m
- R.nr() == rows.size()
- R.nc() == cols.size()
- for all valid r and c:
R(r,c) == m(rows(r),cols(c))
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp subm (
const matrix_exp& m,
long row,
long col,
long nr,
long nc
);
/*!
requires
- row >= 0
- col >= 0
- nr >= 0
- nc >= 0
- row + nr <= m.nr()
- col + nc <= m.nc()
ensures
- returns a matrix R such that:
- R.nr() == nr
- R.nc() == nc
- for all valid r and c:
R(r, c) == m(r+row,c+col)
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp subm (
const matrix_exp& m,
const rectangle& rect
);
/*!
requires
- get_rect(m).contains(rect) == true
(i.e. rect is a region inside the matrix m)
ensures
- returns a matrix R such that:
- R.nr() == rect.height()
- R.nc() == rect.width()
- for all valid r and c:
R(r, c) == m(r+rect.top(), c+rect.left())
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp subm_clipped (
const matrix_exp& m,
long row,
long col,
long nr,
long nc
);
/*!
ensures
- This function is just like subm() except that it will automatically clip the
indicated sub matrix window so that it does not extend outside m.
In particular:
- Let box = rectangle(col,row,col+nc-1,row+nr-1)
(i.e. the box that contains the indicated sub matrix)
- Let box_clipped = box.intersect(get_rect(m))
- Then this function returns a matrix R such that:
- R.nr() == box_clipped.height()
- R.nc() == box_clipped.width()
- for all valid r and c:
R(r, c) == m(r+box_clipped.top(),c+box_clipped.left())
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp subm_clipped (
const matrix_exp& m,
const rectangle& rect
);
/*!
ensures
- Let box_clipped == rect.intersect(get_rect(m))
- returns a matrix R such that:
- R.nr() == box_clipped.height()
- R.nc() == box_clipped.width()
- for all valid r and c:
R(r, c) == m(r+box_clipped.top(), c+box_clipped.left())
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp rowm (
const matrix_exp& m,
long row
);
/*!
requires
- 0 <= row < m.nr()
ensures
- returns a matrix R such that:
- R.nr() == 1
- R.nc() == m.nc()
- for all valid i:
R(i) == m(row,i)
!*/

template <typename EXP>
struct rowm_exp
{
/*!
WHAT THIS OBJECT REPRESENTS
This struct allows you to determine the type of matrix expression
object returned from the rowm(m,row) function.  An example makes its
use clear:

template <typename EXP>
void do_something( const matrix_exp<EXP>& mat)
{
// r is a matrix expression that aliases mat.
typename rowm_exp<EXP>::type r = rowm(mat,0);

// Print the first row of mat.  So we see that by using
// rowm_exp we can save the object returned by rowm() in
// a local variable.
cout << r << endl;

// Note that you can only save the return value of rowm() to
// a local variable if the argument to rowm() has a lifetime
// beyond the rowm() expression.  The example shown above is
// OK but the following would result in undefined behavior:
typename rowm_exp<EXP>::type bad = rowm(mat + mat,0);
}
!*/
typedef type_of_expression_returned_by_rowm type;
};

// ----------------------------------------------------------------------------------------

const matrix_exp rowm (
const matrix_exp& m,
long row,
long length
);
/*!
requires
- 0 <= row < m.nr()
- 0 <= length <= m.nc()
ensures
- returns a matrix R such that:
- R.nr() == 1
- R.nc() == length
- for all valid i:
R(i) == m(row,i)
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp rowm (
const matrix_exp& m,
const matrix_exp& rows
);
/*!
requires
- rows contains integral elements (e.g. int, long)
- 0 <= min(rows) && max(rows) < m.nr()
- rows.nr() == 1 || rows.nc() == 1 || rows.size() == 0
(i.e. rows must be a vector, or just empty)
ensures
- returns a matrix R such that:
- R::type == the same type that was in m
- R.nr() == rows.size()
- R.nc() == m.nc()
- for all valid r and c:
R(r,c) == m(rows(r),c)
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp colm (
const matrix_exp& m,
long col
);
/*!
requires
- 0 <= col < m.nc()
ensures
- returns a matrix R such that:
- R.nr() == m.nr()
- R.nc() == 1
- for all valid i:
R(i) == m(i,col)
!*/

template <typename EXP>
struct colm_exp
{
/*!
WHAT THIS OBJECT REPRESENTS
This struct allows you to determine the type of matrix expression
object returned from the colm(m,col) function.  An example makes its
use clear:

template <typename EXP>
void do_something( const matrix_exp<EXP>& mat)
{
// c is a matrix expression that aliases mat.
typename colm_exp<EXP>::type c = colm(mat,0);

// Print the first column of mat.  So we see that by using
// colm_exp we can save the object returned by colm() in
// a local variable.
cout << c << endl;

// Note that you can only save the return value of colm() to
// a local variable if the argument to colm() has a lifetime
// beyond the colm() expression.  The example shown above is
// OK but the following would result in undefined behavior:
typename colm_exp<EXP>::type bad = colm(mat + mat,0);
}
!*/
typedef type_of_expression_returned_by_colm type;
};

// ----------------------------------------------------------------------------------------

const matrix_exp colm (
const matrix_exp& m,
long col,
long length
);
/*!
requires
- 0 <= col < m.nc()
- 0 <= length <= m.nr()
ensures
- returns a matrix R such that:
- R.nr() == length
- R.nc() == 1
- for all valid i:
R(i) == m(i,col)
!*/

// ----------------------------------------------------------------------------------------

const matrix_exp colm (
const matrix_exp& m,
const matrix_exp& cols
);
/*!
requires
- cols contains integral elements (e.g. int, long)
- 0 <= min(cols) && max(cols) < m.nc()
- cols.nr() == 1 || cols.nc() == 1 || cols.size() == 0
(i.e. cols must be a vector, or just empty)
ensures
- returns a matrix R such that:
- R::type == the same type that was in m
- R.nr() == m.nr()
- R.nc() == cols.size()
- for all valid r and c:
R(r,c) == m(r,cols(c))
!*/

// ----------------------------------------------------------------------------------------

template <typename T>
assignable_matrix_expression set_ptrm (
T* ptr,
long nr,
long nc = 1
);
/*!
requires
- ptr == a pointer to nr*nc elements of type T
- nr >= 0
- nc >= 0
ensures
- statements of the following form:
- set_ptrm(ptr,nr,nc) = some_matrix;
result in it being the case that:
- mat(ptr,nr,nc) == some_matrix.

- statements of the following form:
- set_ptrm(ptr,nr,nc) = scalar_value;
result in it being the case that:
- mat(ptr,nr,nc) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_subm (
matrix& m,
long row,
long col,
long nr,
long nc
);
/*!
requires
- row >= 0
- col >= 0
- nr >= 0
- nc >= 0
- row + nr <= m.nr()
- col + nc <= m.nc()
ensures
- statements of the following form:
- set_subm(m,row,col,nr,nc) = some_matrix;
result in it being the case that:
- subm(m,row,col,nr,nc) == some_matrix.

- statements of the following form:
- set_subm(m,row,col,nr,nc) = scalar_value;
result in it being the case that:
- subm(m,row,col,nr,nc) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_subm (
matrix& m,
const rectangle& rect
);
/*!
requires
- get_rect(m).contains(rect) == true
(i.e. rect is a region inside the matrix m)
ensures
- statements of the following form:
- set_subm(m,rect) = some_matrix;
result in it being the case that:
- subm(m,rect) == some_matrix.

- statements of the following form:
- set_subm(m,rect) = scalar_value;
result in it being the case that:
- subm(m,rect) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_subm (
matrix& m,
const matrix_exp& rows,
const matrix_exp& cols
);
/*!
requires
- rows and cols contain integral elements (e.g. int, long)
- 0 <= min(rows) && max(rows) < m.nr()
- 0 <= min(cols) && max(cols) < m.nc()
- rows.nr() == 1 || rows.nc() == 1
- cols.nr() == 1 || cols.nc() == 1
(i.e. rows and cols must be vectors)
ensures
- statements of the following form:
- set_subm(m,rows,cols) = some_matrix;
result in it being the case that:
- subm(m,rows,cols) == some_matrix.

- statements of the following form:
- set_subm(m,rows,cols) = scalar_value;
result in it being the case that:
- subm(m,rows,cols) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_rowm (
matrix& m,
long row
);
/*!
requires
- 0 <= row < m.nr()
ensures
- statements of the following form:
- set_rowm(m,row) = some_matrix;
result in it being the case that:
- rowm(m,row) == some_matrix.

- statements of the following form:
- set_rowm(m,row) = scalar_value;
result in it being the case that:
- rowm(m,row) == uniform_matrix<matrix::type>(1,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_rowm (
matrix& m,
const matrix_exp& rows
);
/*!
requires
- rows contains integral elements (e.g. int, long)
- 0 <= min(rows) && max(rows) < m.nr()
- rows.nr() == 1 || rows.nc() == 1
(i.e. rows must be a vector)
ensures
- statements of the following form:
- set_rowm(m,rows) = some_matrix;
result in it being the case that:
- rowm(m,rows) == some_matrix.

- statements of the following form:
- set_rowm(m,rows) = scalar_value;
result in it being the case that:
- rowm(m,rows) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_colm (
matrix& m,
long col
);
/*!
requires
- 0 <= col < m.nr()
ensures
- statements of the following form:
- set_colm(m,col) = some_matrix;
result in it being the case that:
- colm(m,col) == some_matrix.

- statements of the following form:
- set_colm(m,col) = scalar_value;
result in it being the case that:
- colm(m,col) == uniform_matrix<matrix::type>(nr,1,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

assignable_matrix_expression set_colm (
matrix& m,
const matrix_exp& cols
);
/*!
requires
- cols contains integral elements (e.g. int, long)
- 0 <= min(cols) && max(cols) < m.nc()
- cols.nr() == 1 || cols.nc() == 1
(i.e. cols must be a vector)
ensures
- statements of the following form:
- set_colm(m,cols) = some_matrix;
result in it being the case that:
- colm(m,cols) == some_matrix.

- statements of the following form:
- set_colm(m,cols) = scalar_value;
result in it being the case that:
- colm(m,cols) == uniform_matrix<matrix::type>(nr,nc,scalar_value).

- In addition to the normal assignment statements using the = symbol, you may
also use the usual += and -= versions of the assignment operator.  In these
cases, they have their usual effect.
!*/

// ----------------------------------------------------------------------------------------

}

#endif // DLIB_MATRIx_SUBEXP_ABSTRACT_

```