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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
//
// Eigen is free software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the Free Software
// Foundation; either version 2 or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
// details.
//
// You should have received a copy of the GNU General Public License along
// with Eigen; if not, write to the Free Software Foundation, Inc., 51
// Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. This exception does not invalidate any other reasons why a work
// based on this file might be covered by the GNU General Public License.
#ifndef EIGEN_BLOCK_H
#define EIGEN_BLOCK_H
/** \class Block
*
* \brief Expression of a dynamic-size block
*
* \param MatrixType the type of the object in which we are taking a block
*
* This class represents an expression of a dynamic-size block. It is the return
* type of MatrixBase::block() and most of the time this is the only way it
* is used.
*
* However, if you want to directly maniputate dynamic-size block expressions,
* for instance if you want to write a function returning such an expression, you
* will need to use this class.
*
* Here is an example illustrating this:
* \include class_Block.cpp
* Output: \verbinclude class_Block.out
*
* \sa MatrixBase::block()
*/
template<typename MatrixType> class Block
: public MatrixBase<typename MatrixType::Scalar, Block<MatrixType> >
{
public:
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::Ref MatRef;
friend class MatrixBase<Scalar, Block<MatrixType> >;
Block(const MatRef& matrix,
int startRow, int startCol,
int blockRows, int blockCols)
: m_matrix(matrix), m_startRow(startRow), m_startCol(startCol),
m_blockRows(blockRows), m_blockCols(blockCols)
{
assert(startRow >= 0 && blockRows >= 1 && startRow + blockRows <= matrix.rows()
&& startCol >= 0 && blockCols >= 1 && startCol + blockCols <= matrix.cols());
}
EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Block)
private:
enum {
RowsAtCompileTime = MatrixType::Traits::RowsAtCompileTime == 1 ? 1 : Dynamic,
ColsAtCompileTime = MatrixType::Traits::ColsAtCompileTime == 1 ? 1 : Dynamic,
MaxRowsAtCompileTime = RowsAtCompileTime == 1 ? 1 : MatrixType::Traits::MaxRowsAtCompileTime,
MaxColsAtCompileTime = ColsAtCompileTime == 1 ? 1 : MatrixType::Traits::MaxColsAtCompileTime
};
const Block& _ref() const { return *this; }
int _rows() const { return m_blockRows; }
int _cols() const { return m_blockCols; }
Scalar& _coeffRef(int row, int col)
{
return m_matrix.coeffRef(row + m_startRow, col + m_startCol);
}
Scalar _coeff(int row, int col) const
{
return m_matrix.coeff(row + m_startRow, col + m_startCol);
}
protected:
MatRef m_matrix;
const int m_startRow, m_startCol, m_blockRows, m_blockCols;
};
/** \returns a dynamic-size expression of a block in *this.
*
* \param startRow the first row in the block
* \param startCol the first column in the block
* \param blockRows the number of rows in the block
* \param blockCols the number of columns in the block
*
* Example: \include MatrixBase_block.cpp
* Output: \verbinclude MatrixBase_block.out
*
* \sa class Block, fixedBlock()
*/
template<typename Scalar, typename Derived>
Block<Derived> MatrixBase<Scalar, Derived>
::block(int startRow, int startCol, int blockRows, int blockCols)
{
return Block<Derived>(ref(), startRow, startCol, blockRows, blockCols);
}
/** This is the const version of block(). */
template<typename Scalar, typename Derived>
const Block<Derived> MatrixBase<Scalar, Derived>
::block(int startRow, int startCol, int blockRows, int blockCols) const
{
return Block<Derived>(ref(), startRow, startCol, blockRows, blockCols);
}
#endif // EIGEN_BLOCK_H
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