// This file is part of Eigen, a lightweight C++ template library // for linear algebra. // // Copyright (C) 2008-2009 Gael Guennebaud // Copyright (C) 2006-2008 Benoit Jacob // // 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 EIGEN_ORTHOMETHODS_H #define EIGEN_ORTHOMETHODS_H namespace Eigen { /** \geometry_module * * \returns the cross product of \c *this and \a other * * Here is a very good explanation of cross-product: http://xkcd.com/199/ * \sa MatrixBase::cross3() */ template template inline typename MatrixBase::template cross_product_return_type::type MatrixBase::cross(const MatrixBase& other) const { EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(Derived,3) EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(OtherDerived,3) // Note that there is no need for an expression here since the compiler // optimize such a small temporary very well (even within a complex expression) typename internal::nested::type lhs(derived()); typename internal::nested::type rhs(other.derived()); return typename cross_product_return_type::type( numext::conj(lhs.coeff(1) * rhs.coeff(2) - lhs.coeff(2) * rhs.coeff(1)), numext::conj(lhs.coeff(2) * rhs.coeff(0) - lhs.coeff(0) * rhs.coeff(2)), numext::conj(lhs.coeff(0) * rhs.coeff(1) - lhs.coeff(1) * rhs.coeff(0)) ); } namespace internal { template< int Arch,typename VectorLhs,typename VectorRhs, typename Scalar = typename VectorLhs::Scalar, bool Vectorizable = bool((VectorLhs::Flags&VectorRhs::Flags)&PacketAccessBit)> struct cross3_impl { static inline typename internal::plain_matrix_type::type run(const VectorLhs& lhs, const VectorRhs& rhs) { return typename internal::plain_matrix_type::type( numext::conj(lhs.coeff(1) * rhs.coeff(2) - lhs.coeff(2) * rhs.coeff(1)), numext::conj(lhs.coeff(2) * rhs.coeff(0) - lhs.coeff(0) * rhs.coeff(2)), numext::conj(lhs.coeff(0) * rhs.coeff(1) - lhs.coeff(1) * rhs.coeff(0)), 0 ); } }; } /** \geometry_module * * \returns the cross product of \c *this and \a other using only the x, y, and z coefficients * * The size of \c *this and \a other must be four. This function is especially useful * when using 4D vectors instead of 3D ones to get advantage of SSE/AltiVec vectorization. * * \sa MatrixBase::cross() */ template template inline typename MatrixBase::PlainObject MatrixBase::cross3(const MatrixBase& other) const { EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(Derived,4) EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(OtherDerived,4) typedef typename internal::nested::type DerivedNested; typedef typename internal::nested::type OtherDerivedNested; DerivedNested lhs(derived()); OtherDerivedNested rhs(other.derived()); return internal::cross3_impl::type, typename internal::remove_all::type>::run(lhs,rhs); } /** \returns a matrix expression of the cross product of each column or row * of the referenced expression with the \a other vector. * * The referenced matrix must have one dimension equal to 3. * The result matrix has the same dimensions than the referenced one. * * \geometry_module * * \sa MatrixBase::cross() */ template template const typename VectorwiseOp::CrossReturnType VectorwiseOp::cross(const MatrixBase& other) const { EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(OtherDerived,3) EIGEN_STATIC_ASSERT((internal::is_same::value), YOU_MIXED_DIFFERENT_NUMERIC_TYPES__YOU_NEED_TO_USE_THE_CAST_METHOD_OF_MATRIXBASE_TO_CAST_NUMERIC_TYPES_EXPLICITLY) CrossReturnType res(_expression().rows(),_expression().cols()); if(Direction==Vertical) { eigen_assert(CrossReturnType::RowsAtCompileTime==3 && "the matrix must have exactly 3 rows"); res.row(0) = (_expression().row(1) * other.coeff(2) - _expression().row(2) * other.coeff(1)).conjugate(); res.row(1) = (_expression().row(2) * other.coeff(0) - _expression().row(0) * other.coeff(2)).conjugate(); res.row(2) = (_expression().row(0) * other.coeff(1) - _expression().row(1) * other.coeff(0)).conjugate(); } else { eigen_assert(CrossReturnType::ColsAtCompileTime==3 && "the matrix must have exactly 3 columns"); res.col(0) = (_expression().col(1) * other.coeff(2) - _expression().col(2) * other.coeff(1)).conjugate(); res.col(1) = (_expression().col(2) * other.coeff(0) - _expression().col(0) * other.coeff(2)).conjugate(); res.col(2) = (_expression().col(0) * other.coeff(1) - _expression().col(1) * other.coeff(0)).conjugate(); } return res; } namespace internal { template struct unitOrthogonal_selector { typedef typename plain_matrix_type::type VectorType; typedef typename traits::Scalar Scalar; typedef typename NumTraits::Real RealScalar; typedef typename Derived::Index Index; typedef Matrix Vector2; static inline VectorType run(const Derived& src) { VectorType perp = VectorType::Zero(src.size()); Index maxi = 0; Index sndi = 0; src.cwiseAbs().maxCoeff(&maxi); if (maxi==0) sndi = 1; RealScalar invnm = RealScalar(1)/(Vector2() << src.coeff(sndi),src.coeff(maxi)).finished().norm(); perp.coeffRef(maxi) = -numext::conj(src.coeff(sndi)) * invnm; perp.coeffRef(sndi) = numext::conj(src.coeff(maxi)) * invnm; return perp; } }; template struct unitOrthogonal_selector { typedef typename plain_matrix_type::type VectorType; typedef typename traits::Scalar Scalar; typedef typename NumTraits::Real RealScalar; static inline VectorType run(const Derived& src) { VectorType perp; /* Let us compute the crossed product of *this with a vector * that is not too close to being colinear to *this. */ /* unless the x and y coords are both close to zero, we can * simply take ( -y, x, 0 ) and normalize it. */ if((!isMuchSmallerThan(src.x(), src.z())) || (!isMuchSmallerThan(src.y(), src.z()))) { RealScalar invnm = RealScalar(1)/src.template head<2>().norm(); perp.coeffRef(0) = -numext::conj(src.y())*invnm; perp.coeffRef(1) = numext::conj(src.x())*invnm; perp.coeffRef(2) = 0; } /* if both x and y are close to zero, then the vector is close * to the z-axis, so it's far from colinear to the x-axis for instance. * So we take the crossed product with (1,0,0) and normalize it. */ else { RealScalar invnm = RealScalar(1)/src.template tail<2>().norm(); perp.coeffRef(0) = 0; perp.coeffRef(1) = -numext::conj(src.z())*invnm; perp.coeffRef(2) = numext::conj(src.y())*invnm; } return perp; } }; template struct unitOrthogonal_selector { typedef typename plain_matrix_type::type VectorType; static inline VectorType run(const Derived& src) { return VectorType(-numext::conj(src.y()), numext::conj(src.x())).normalized(); } }; } // end namespace internal /** \returns a unit vector which is orthogonal to \c *this * * The size of \c *this must be at least 2. If the size is exactly 2, * then the returned vector is a counter clock wise rotation of \c *this, i.e., (-y,x).normalized(). * * \sa cross() */ template typename MatrixBase::PlainObject MatrixBase::unitOrthogonal() const { EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived) return internal::unitOrthogonal_selector::run(derived()); } } // end namespace Eigen #endif // EIGEN_ORTHOMETHODS_H