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* remove Cross product expression: MatrixBase::cross() now returns a temporary

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which is even better optimized by the compiler.
* Quaternion no longer inherits MatrixBase. Instead it stores the coefficients
  using a Matrix<> and provides only relevant methods.
This commit is contained in:
Gael Guennebaud
2008-06-07 13:18:29 +00:00
parent 6998037930
commit eb7b7b2cfc
5 changed files with 113 additions and 186 deletions
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81
Eigen/src/Geometry/Cross.h
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@@ -25,78 +25,21 @@
#ifndef EIGEN_CROSS_H
#define EIGEN_CROSS_H
/** \class Cross
*
* \brief Expression of the cross product of two vectors
*
* \param Lhs the type of the left-hand side
* \param Rhs the type of the right-hand side
*
* This class represents an expression of the cross product of two 3D vectors.
* It is the return type of MatrixBase::cross(), and most
* of the time this is the only way it is used.
*/
template<typename Lhs, typename Rhs>
struct ei_traits<Cross<Lhs, Rhs> >
{
typedef typename Lhs::Scalar Scalar;
typedef typename ei_nested<Lhs,2>::type LhsNested;
typedef typename ei_nested<Rhs,2>::type RhsNested;
typedef typename ei_unref<LhsNested>::type _LhsNested;
typedef typename ei_unref<RhsNested>::type _RhsNested;
enum {
RowsAtCompileTime = 3,
ColsAtCompileTime = 1,
MaxRowsAtCompileTime = 3,
MaxColsAtCompileTime = 1,
Flags = ((_RhsNested::Flags | _LhsNested::Flags) & HereditaryBits)
| EvalBeforeAssigningBit,
CoeffReadCost = NumTraits<Scalar>::AddCost + 2 * NumTraits<Scalar>::MulCost
};
};
template<typename Lhs, typename Rhs> class Cross : ei_no_assignment_operator,
public MatrixBase<Cross<Lhs, Rhs> >
{
public:
EIGEN_GENERIC_PUBLIC_INTERFACE(Cross)
typedef typename ei_traits<Cross>::LhsNested LhsNested;
typedef typename ei_traits<Cross>::RhsNested RhsNested;
Cross(const Lhs& lhs, const Rhs& rhs)
: m_lhs(lhs), m_rhs(rhs)
{
assert(lhs.isVector());
assert(rhs.isVector());
assert(lhs.size() == 3 && rhs.size() == 3);
}
private:
int _rows() const { return 3; }
int _cols() const { return 1; }
Scalar _coeff(int i, int) const
{
return m_lhs[(i+1)%3]*m_rhs[(i+2)%3] - m_lhs[(i+2)%3]*m_rhs[(i+1)%3];
}
protected:
const LhsNested m_lhs;
const RhsNested m_rhs;
};
/** \returns an expression of the cross product of \c *this and \a other
*
* \sa class Cross
*/
/** \returns the cross product of \c *this and \a other */
template<typename Derived>
template<typename OtherDerived>
const Cross<Derived,OtherDerived>
MatrixBase<Derived>::cross(const MatrixBase<OtherDerived>& other) const
typename ei_eval<Derived>::type
inline MatrixBase<Derived>::cross(const MatrixBase<OtherDerived>& other) const
{
return Cross<Derived,OtherDerived>(derived(),other.derived());
// 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());
const typename ei_nested<OtherDerived,2>::type rhs(other.derived());
return typename ei_eval<Derived>::type(
lhs.coeff(1) * rhs.coeff(2) - lhs.coeff(2) * rhs.coeff(1),
lhs.coeff(2) * rhs.coeff(0) - lhs.coeff(0) * rhs.coeff(2),
lhs.coeff(0) * rhs.coeff(1) - lhs.coeff(1) * rhs.coeff(0)
);
}
#endif // EIGEN_CROSS_H