121 lines
3.1 KiB
C++
121 lines
3.1 KiB
C++
// Copyright (c) 1998-2003 ETH Zurich (Switzerland).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org).
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Matrix_search/include/CGAL/Dynamic_matrix.h $
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// $Id: Dynamic_matrix.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
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//
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//
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// Author(s) : Michael Hoffmann <hoffmann@inf.ethz.ch>
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#ifndef CGAL_DYNAMIC_MATRIX_H
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#define CGAL_DYNAMIC_MATRIX_H 1
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#include <CGAL/license/Matrix_search.h>
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#include <vector>
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#include <utility>
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#include <CGAL/Optimisation/assertions.h>
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namespace CGAL {
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template < class Matrix >
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class Dynamic_matrix
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// adaptor for a matrix class
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// to allow replacement of columns in constant time
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// and extraction of all even rows in linear time
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{
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public:
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typedef std::vector< int > CoordContainer;
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typedef Dynamic_matrix< Matrix > ThisMatrixClass;
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typedef typename Matrix::Value Value;
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Dynamic_matrix( const Matrix& m, int r_p = 0)
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: matrix( &m),
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column_indices( m.number_of_columns()),
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row_power( r_p),
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row_offset( (1 << r_p) - 1)
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{
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for ( unsigned int i( 0); i < column_indices.size(); ++i)
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column_indices[i] = i;
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}
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int
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number_of_rows() const
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{
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return ( matrix->number_of_rows() + row_offset) >> row_power;
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}
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int
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number_of_columns() const
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{ return static_cast<int>(column_indices.size()); }
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Value
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operator()( int r, int c) const
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{
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CGAL_optimisation_precondition( r >= 0 && r < number_of_rows());
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CGAL_optimisation_precondition( c >= 0 && c < number_of_columns());
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return (*matrix)( r << row_power, column_indices[c]);
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}
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Value
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operator()( std::pair< int, int > p) const
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{
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return (*this)( p.first, p.second);
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}
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void
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replace_column( int o, int n)
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{
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CGAL_optimisation_precondition( o >= 0 && o < number_of_columns());
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CGAL_optimisation_precondition( n >= 0 && n < number_of_columns());
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column_indices[o] = column_indices[n];
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}
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void
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shrink_to_quadratic_size()
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{
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CGAL_optimisation_precondition( number_of_columns() >= number_of_rows());
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column_indices.erase( column_indices.begin() + number_of_rows(),
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column_indices.end());
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CGAL_optimisation_postcondition( number_of_columns() == number_of_rows());
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}
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private:
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Dynamic_matrix( const Matrix* m, const CoordContainer& c_i, int r_p)
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: matrix( m),
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column_indices( c_i),
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row_power( r_p),
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row_offset( (1 << r_p) - 1)
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{}
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public:
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ThisMatrixClass*
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extract_all_even_rows() const
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{
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return new ThisMatrixClass( matrix, column_indices, row_power + 1);
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}
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private:
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const Matrix* matrix;
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CoordContainer column_indices;
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int row_power;
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int row_offset;
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};
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template < class Matrix >
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inline
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Dynamic_matrix< Matrix >
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dynamic_matrix( const Matrix& m)
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{ return Dynamic_matrix< Matrix >( m); }
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} //namespace CGAL
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#endif // ! (CGAL_DYNAMIC_MATRIX_H)
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// ----------------------------------------------------------------------------
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// ** EOF
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// ----------------------------------------------------------------------------
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