/*
 * $Revision: 2597 $
 *
 * last checkin:
 *   $Author: gutwenger $
 *   $Date: 2012-07-15 19:26:11 +0200 (So, 15. Jul 2012) $
 ***************************************************************/

/** \file
 * \brief Declaration of basic page rank.
 *
 * \author Martin Gronemann
 *
 * \par License:
 * This file is part of the Open Graph Drawing Framework (OGDF).
 *
 * \par
 * Copyright (C)<br>
 * See README.txt in the root directory of the OGDF installation for details.
 *
 * \par
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * Version 2 or 3 as published by the Free Software Foundation;
 * see the file LICENSE.txt included in the packaging of this file
 * for details.
 *
 * \par
 * This program 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.
 *
 * \par
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * \see  http://www.gnu.org/copyleft/gpl.html
 ***************************************************************/

#ifndef OGDF_PAGE_RANK_H_
#define OGDF_PAGE_RANK_H_

#include <ogdf/basic/NodeArray.h>
#include <ogdf/basic/EdgeArray.h>

namespace ogdf {

//! Basic page rank calculation
class BasicPageRank
{
public:
	BasicPageRank()
	{
		initDefaultOptions();
	}

	//! main algorithm call
	void call(
		const Graph& graph,
		const EdgeArray<double>& edgeWeight,
		NodeArray<double>& pageRankResult);

	//! sets the default options.
	void initDefaultOptions()
	{
		m_dampingFactor		= 0.85;
		m_maxNumIterations	= 1000;
		m_threshold			= 0.0;
	}

	//! returns the damping factor for each iteration (default is 0.85)
	double dampingFactor() const
	{
		return m_dampingFactor;
	}

	//! sets the damping factor for each iteration (default is 0.85)
	void setDampingFactor(double dampingFactor)
	{
		m_dampingFactor = dampingFactor;
	}

	//! the maximum number of iterations (default is 1000)
	int maxNumIterations() const
	{
		return m_maxNumIterations;
	}

	//! sets the maximum number of iterations (default is 1000)
	void setMaxNumIterations(int maxNumIterations)
	{
		m_maxNumIterations = maxNumIterations;
	}

	/*! returns the threshold/epsilon. After each iteration the result is compared to
	 * to the old one and in case all changes are smaller than threshold the algorithm
	 * stops. Note that the default value is 0.0 resulting in maxNumIterations usually.
	 */
	double threshold() const
	{
		return m_threshold;
	}


	//! sets the threshold to t. See threshold for more information
	void setThreshold(double t)
	{
		m_threshold = t;
	}

private:
	//! the damping factor
	double m_dampingFactor;

	//! maximum number of iterations
	int m_maxNumIterations;

	//! the threshold
	double m_threshold;
};

} // end of namespace ogdf

#endif // OGDF_PAGE_RANK_H_

