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Add .perpendicular() function in Geometry module (adapted from Eigen1)

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Documentation:
 * add an overview for each module.
 * add an example for .all() and Cwise::operator<
This commit is contained in:
Gael Guennebaud
2008-07-22 10:54:42 +00:00
parent 516db2c3b9
commit 172000aaeb
22 changed files with 189 additions and 36 deletions
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64
Eigen/src/Geometry/Cross.h
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@@ -2,6 +2,7 @@
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
@@ -32,6 +33,8 @@ template<typename OtherDerived>
inline typename ei_eval<Derived>::type
MatrixBase<Derived>::cross(const MatrixBase<OtherDerived>& other) const
{
EIGEN_STATIC_ASSERT_VECTOR_SPECIFIC_SIZE(Derived,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)
const typename ei_nested<Derived,2>::type lhs(derived());
@@ -43,4 +46,65 @@ MatrixBase<Derived>::cross(const MatrixBase<OtherDerived>& other) const
);
}
template<typename Derived, int Size = Derived::SizeAtCompileTime>
struct ei_perpendicular_selector
{
typedef typename ei_eval<Derived>::type VectorType;
typedef typename ei_traits<Derived>::Scalar Scalar;
inline static 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((!ei_isMuchSmallerThan(src.x(), src.z()))
|| (!ei_isMuchSmallerThan(src.y(), src.z())))
{
Scalar invnm = Scalar(1)/src.template start<2>().norm();
perp.template start<3>() << -ei_conj(src.y())*invnm, ei_conj(src.x())*invnm, 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
{
Scalar invnm = Scalar(1)/src.template end<2>().norm();
perp.template start<3>() << 0, -ei_conj(src.z())*invnm, ei_conj(src.y())*invnm;
}
if (Derived::SizeAtCompileTime>3
|| (Derived::SizeAtCompileTime==Dynamic && src.size()>3))
perp.end(src.size()-3).setZero();
return perp;
}
};
template<typename Derived>
struct ei_perpendicular_selector<Derived,2>
{
typedef typename ei_eval<Derived>::type VectorType;
inline static VectorType run(const Derived& src)
{ return VectorType(-ei_conj(src.y()), ei_conj(src.x())).normalized(); }
};
/** \Returns an orthogonal vector of \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, \ie (-y,x).
*
* \sa cross()
*/
template<typename Derived>
typename ei_eval<Derived>::type
MatrixBase<Derived>::perpendicular() const
{
EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived);
return ei_perpendicular_selector<Derived>::run(derived());
}
#endif // EIGEN_CROSS_H