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130 lines
4.7 KiB
C++
130 lines
4.7 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra. Eigen itself is part of the KDE project.
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//
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// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
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//
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// Eigen is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 3 of the License, or (at your option) any later version.
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//
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// Alternatively, you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of
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// the License, or (at your option) any later version.
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//
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// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License and a copy of the GNU General Public License along with
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// Eigen. If not, see <http://www.gnu.org/licenses/>.
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#ifndef EIGEN_FIXEDBLOCK_H
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#define EIGEN_FIXEDBLOCK_H
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/** \class FixedBlock
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*
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* \brief Expression of a fixed-size block
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*
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* \param MatrixType the type of the object in which we are taking a block
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* \param BlockRows the number of rows of the block we are taking
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* \param BlockCols the number of columns of the block we are taking
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*
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* This class represents an expression of a fixed-size block. It is the return
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* type of MatrixBase::fixedBlock() and most of the time this is the only way it
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* is used.
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*
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* However, if you want to directly maniputate fixed-size block expressions,
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* for instance if you want to write a function returning such an expression, you
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* will need to use this class.
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*
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* Here is an example illustrating this:
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* \include class_FixedBlock.cpp
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* Output: \verbinclude class_FixedBlock.out
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*
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* \sa MatrixBase::fixedBlock(int,int), class Block
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*/
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template<typename MatrixType, int BlockRows, int BlockCols> class FixedBlock
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: public MatrixBase<typename MatrixType::Scalar,
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FixedBlock<MatrixType, BlockRows, BlockCols> >
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{
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public:
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typedef typename MatrixType::Scalar Scalar;
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typedef typename MatrixType::Ref MatRef;
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friend class MatrixBase<Scalar, FixedBlock>;
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typedef MatrixBase<Scalar, FixedBlock> Base;
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FixedBlock(const MatRef& matrix, int startRow, int startCol)
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: m_matrix(matrix), m_startRow(startRow), m_startCol(startCol)
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{
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assert(startRow >= 0 && BlockRows >= 1 && startRow + BlockRows <= matrix.rows()
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&& startCol >= 0 && BlockCols >= 1 && startCol + BlockCols <= matrix.cols());
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}
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EIGEN_INHERIT_ASSIGNMENT_OPERATORS(FixedBlock)
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private:
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enum{
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RowsAtCompileTime = BlockRows,
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ColsAtCompileTime = BlockCols,
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MaxRowsAtCompileTime = BlockRows,
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MaxColsAtCompileTime = BlockCols
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};
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const FixedBlock& _ref() const { return *this; }
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static int _rows() { return BlockRows; }
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static int _cols() { return BlockCols; }
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Scalar& _coeffRef(int row, int col)
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{
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return m_matrix.coeffRef(row + m_startRow.value(), col + m_startCol.value());
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}
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Scalar _coeff(int row, int col) const
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{
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return m_matrix.coeff(row + m_startRow.value(), col + m_startCol.value());
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}
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protected:
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MatRef m_matrix;
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IntAtRunTimeIfDynamic<MatrixType::Traits::RowsAtCompileTime == 1 ? 0 : Dynamic>
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m_startRow;
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IntAtRunTimeIfDynamic<MatrixType::Traits::ColsAtCompileTime == 1 ? 0 : Dynamic>
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m_startCol;
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};
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/** \returns a fixed-size expression of a block in *this.
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*
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* The template parameters \a BlockRows and \a BlockCols are the number of
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* rows and columns in the block.
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*
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* \param startRow the first row in the block
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* \param startCol the first column in the block
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*
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* Example: \include MatrixBase_fixedBlock_int_int.cpp
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* Output: \verbinclude MatrixBase_fixedBlock_int_int.out
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*
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* \sa class FixedBlock, block(int,int,int,int)
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*/
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template<typename Scalar, typename Derived>
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template<int BlockRows, int BlockCols>
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FixedBlock<Derived, BlockRows, BlockCols> MatrixBase<Scalar, Derived>
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::fixedBlock(int startRow, int startCol)
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{
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return FixedBlock<Derived, BlockRows, BlockCols>(ref(), startRow, startCol);
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}
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/** This is the const version of fixedBlock(int, int). */
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template<typename Scalar, typename Derived>
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template<int BlockRows, int BlockCols>
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const FixedBlock<Derived, BlockRows, BlockCols> MatrixBase<Scalar, Derived>
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::fixedBlock(int startRow, int startCol) const
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{
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return FixedBlock<Derived, BlockRows, BlockCols>(ref(), startRow, startCol);
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}
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#endif // EIGEN_FIXEDBLOCK_H
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