dust3d/third_party/libigl/include/igl/polar_svd3x3.h

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// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla Public License
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
// obtain one at http://mozilla.org/MPL/2.0/.
#ifndef IGL_POLAR_SVD3X3_H
#define IGL_POLAR_SVD3X3_H
#include <Eigen/Core>
#include "igl_inline.h"
namespace igl
{
// Computes the closest rotation to input matrix A using specialized 3x3 SVD
// singular value decomposition (WunderSVD3x3)
//
// Inputs:
// A 3 by 3 matrix to be decomposed
// Outputs:
// R 3 by 3 closest element in SO(3) (closeness in terms of Frobenius
// metric)
//
// This means that det(R) = 1. Technically it's not polar decomposition
// which guarantees positive semidefinite stretch factor (at the cost of
// having det(R) = -1). "• The orthogonal factors U and V will be true
// rotation matrices..." [McAdams, Selle, Tamstorf, Teran, Sefakis 2011]
//
template<typename Mat>
IGL_INLINE void polar_svd3x3(const Mat& A, Mat& R);
#ifdef __SSE__
template<typename T>
IGL_INLINE void polar_svd3x3_sse(const Eigen::Matrix<T, 3*4, 3>& A, Eigen::Matrix<T, 3*4, 3> &R);
#endif
#ifdef __AVX__
template<typename T>
IGL_INLINE void polar_svd3x3_avx(const Eigen::Matrix<T, 3*8, 3>& A, Eigen::Matrix<T, 3*8, 3> &R);
#endif
}
#ifndef IGL_STATIC_LIBRARY
# include "polar_svd3x3.cpp"
#endif
#endif