vcglib/vcg/math/polar_decomposition.h

/****************************************************************************
* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
*                                                                _   O  _   *
* Copyright(C) 2004-2016                                           \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
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* 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 (http://www.gnu.org/licenses/gpl.txt)          *
* for more details.                                                         *
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****************************************************************************/
#ifndef POLAR_DECOMPOSITION_VCG
#define POLAR_DECOMPOSITION_VCG


#include <vcg/math/matrix33.h>
#include <vcg/math/matrix44.h>
#include <Eigen/Dense>
#include <Eigen/SVD>

namespace vcg{

	/** \addtogroup math */
	/* @{ */
	/// Extract the rotational part of a matrix by polar decomposition
	/// m = R*S. Polar decomposition is computed by taking r = m * sqrt(m^t*m)^{-1}
template <class S>
void RotationalPartByPolarDecomposition( const vcg::Matrix33<S> & m, vcg::Matrix33<S> &r ){

	Eigen::Matrix<S,3,3> tmp,s;

	r.setZero();
	s.setZero();

	tmp = m*m.transpose();

	Eigen::Matrix<S,3,3> res;
	Eigen::Matrix<S,3,3> e;

	bool ss = SingularValueDecomposition<vcg::Matrix33<S> >(tmp,&e[0],res);

    Eigen::JacobiSVD<Eigen::MatrixXd> svd(A);
    sol=svd.solve(b);

	e[0]=math::Sqrt(e[0]);
	e[1]=math::Sqrt(e[1]);
	e[2]=math::Sqrt(e[2]);
	tmp = tmp*e.asDiagonal()*res.transpose();

	bool s1 = SingularValueDecomposition<vcg::Matrix33<S> >(tmp,&e[0],res.transpose());
	e[0]=1/e[0];
	e[1]=1/e[1];
	e[2]=1/e[2];

	tmp = res*e.asDiagonal()*tmp.transpose();
	r = m*tmp;
}

/*! @} */
};
#endif