add computeRotationScaling and computeScalingRotation in SVD

add convenience functions in Transform
reimplement Transform::rotation() to use that
add unit-test
This commit is contained in:
Benoit Jacob 2009-01-22 16:39:08 +00:00
parent 876b1fb842
commit 291ee89684
3 changed files with 138 additions and 43 deletions

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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) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
@ -247,7 +248,11 @@ public:
template<typename Derived>
inline Transform operator*(const RotationBase<Derived,Dim>& r) const;
LinearMatrixType rotation(TransformTraits traits = Affine) const;
LinearMatrixType rotation() const;
template<typename RotationMatrixType, typename ScalingMatrixType>
void computeRotationScaling(RotationMatrixType *rotation, ScalingMatrixType *scaling) const;
template<typename ScalingMatrixType, typename RotationMatrixType>
void computeScalingRotation(ScalingMatrixType *scaling, RotationMatrixType *rotation) const;
template<typename PositionDerived, typename OrientationType, typename ScaleDerived>
Transform& fromPositionOrientationScale(const MatrixBase<PositionDerived> &position,
@ -589,48 +594,61 @@ inline Transform<Scalar,Dim> Transform<Scalar,Dim>::operator*(const RotationBase
return res;
}
/***************************
*** Specialial functions ***
***************************/
/************************
*** Special functions ***
************************/
/** \returns the rotation part of the transformation
* \nonstableyet
*
* \param traits allows to optimize the extraction process when the transformion
* is known to be not a general aafine transformation. The possible values are:
* - Affine which use a QR decomposition (default),
* - Isometry which simply returns the linear part !
* \svd_module
*
* \warning this function consider the scaling is positive
*
* \warning to use this method in the general case (traits==GenericAffine), you need
* to include the QR module.
*
* \sa inverse(), class QR
* \sa computeRotationScaling(), computeScalingRotation(), class SVD
*/
template<typename Scalar, int Dim>
typename Transform<Scalar,Dim>::LinearMatrixType
Transform<Scalar,Dim>::rotation(TransformTraits traits) const
Transform<Scalar,Dim>::rotation() const
{
ei_assert(traits!=Projective && "you cannot extract a rotation from a non affine transformation");
if (traits == Affine)
{
// FIXME maybe QR should be fixed to return a R matrix with a positive diagonal ??
QR<LinearMatrixType> qr(linear());
LinearMatrixType matQ = qr.matrixQ();
LinearMatrixType matR = qr.matrixR();
for (int i=0 ; i<Dim; ++i)
if (matR.coeff(i,i)<0)
matQ.col(i) = -matQ.col(i);
return matQ;
}
else if (traits == Isometry) // though that's stupid let's handle it !
return linear(); // FIXME needs to divide by determinant
else
{
ei_assert("invalid traits value in Transform::rotation()");
return LinearMatrixType();
}
LinearMatrixType result;
computeRotationScaling(&result, (LinearMatrixType*)0);
return result;
}
/** decomposes the linear part of the transformation as a product rotation x scaling, the scaling being
* not necessarily positive.
*
* If either pointer is zero, the corresponding computation is skipped.
*
* \nonstableyet
*
* \svd_module
*
* \sa computeScalingRotation(), rotation(), class SVD
*/
template<typename Scalar, int Dim>
template<typename RotationMatrixType, typename ScalingMatrixType>
void Transform<Scalar,Dim>::computeRotationScaling(RotationMatrixType *rotation, ScalingMatrixType *scaling) const
{
linear().svd().computeRotationScaling(rotation, scaling);
}
/** decomposes the linear part of the transformation as a product rotation x scaling, the scaling being
* not necessarily positive.
*
* If either pointer is zero, the corresponding computation is skipped.
*
* \nonstableyet
*
* \svd_module
*
* \sa computeRotationScaling(), rotation(), class SVD
*/
template<typename Scalar, int Dim>
template<typename ScalingMatrixType, typename RotationMatrixType>
void Transform<Scalar,Dim>::computeScalingRotation(ScalingMatrixType *scaling, RotationMatrixType *rotation) const
{
linear().svd().computeScalingRotation(scaling, rotation);
}
/** Convenient method to set \c *this from a position, orientation and scale

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@ -79,8 +79,14 @@ template<typename MatrixType> class SVD
void compute(const MatrixType& matrix);
SVD& sort();
void computeUnitaryPositive(MatrixUType *unitary, MatrixType *positive) const;
void computePositiveUnitary(MatrixType *positive, MatrixVType *unitary) const;
template<typename UnitaryType, typename PositiveType>
void computeUnitaryPositive(UnitaryType *unitary, PositiveType *positive) const;
template<typename PositiveType, typename UnitaryType>
void computePositiveUnitary(PositiveType *positive, UnitaryType *unitary) const;
template<typename RotationType, typename ScalingType>
void computeRotationScaling(RotationType *unitary, ScalingType *positive) const;
template<typename ScalingType, typename RotationType>
void computeScalingRotation(ScalingType *positive, RotationType *unitary) const;
protected:
/** \internal */
@ -542,10 +548,13 @@ bool SVD<MatrixType>::solve(const MatrixBase<OtherDerived> &b, ResultType* resul
* If either pointer is zero, the corresponding computation is skipped.
*
* Only for square matrices.
*
* \sa computePositiveUnitary(), computeRotationScaling()
*/
template<typename MatrixType>
void SVD<MatrixType>::computeUnitaryPositive(typename SVD<MatrixType>::MatrixUType *unitary,
MatrixType *positive) const
template<typename UnitaryType, typename PositiveType>
void SVD<MatrixType>::computeUnitaryPositive(UnitaryType *unitary,
PositiveType *positive) const
{
ei_assert(m_matU.cols() == m_matV.cols() && "Polar decomposition is only for square matrices");
if(unitary) *unitary = m_matU * m_matV.adjoint();
@ -557,16 +566,72 @@ void SVD<MatrixType>::computeUnitaryPositive(typename SVD<MatrixType>::MatrixUTy
* If either pointer is zero, the corresponding computation is skipped.
*
* Only for square matrices.
*
* \sa computeUnitaryPositive(), computeRotationScaling()
*/
template<typename MatrixType>
void SVD<MatrixType>::computePositiveUnitary(MatrixType *positive,
typename SVD<MatrixType>::MatrixVType *unitary) const
template<typename UnitaryType, typename PositiveType>
void SVD<MatrixType>::computePositiveUnitary(UnitaryType *positive,
PositiveType *unitary) const
{
ei_assert(m_matU.rows() == m_matV.rows() && "Polar decomposition is only for square matrices");
if(unitary) *unitary = m_matU * m_matV.adjoint();
if(positive) *positive = m_matU * m_sigma.asDiagonal() * m_matU.adjoint();
}
/** decomposes the matrix as a product rotation x scaling, the scaling being
* not necessarily positive.
*
* If either pointer is zero, the corresponding computation is skipped.
*
* This method requires the Geometry module.
*
* \sa computeScalingRotation(), computeUnitaryPositive()
*/
template<typename MatrixType>
template<typename RotationType, typename ScalingType>
void SVD<MatrixType>::computeRotationScaling(RotationType *rotation, ScalingType *scaling) const
{
ei_assert(m_matU.rows() == m_matV.rows() && "Polar decomposition is only for square matrices");
Scalar x = (m_matU * m_matV.adjoint()).determinant(); // so x has absolute value 1
Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> sv(m_sigma);
sv.coeffRef(0) *= x;
if(scaling) scaling->lazyAssign(m_matV * sv.asDiagonal() * m_matV.adjoint());
if(rotation)
{
MatrixType m(m_matU);
m.col(0) /= x;
rotation->lazyAssign(m * m_matV.adjoint());
}
}
/** decomposes the matrix as a product scaling x rotation, the scaling being
* not necessarily positive.
*
* If either pointer is zero, the corresponding computation is skipped.
*
* This method requires the Geometry module.
*
* \sa computeRotationScaling(), computeUnitaryPositive()
*/
template<typename MatrixType>
template<typename ScalingType, typename RotationType>
void SVD<MatrixType>::computeScalingRotation(ScalingType *scaling, RotationType *rotation) const
{
ei_assert(m_matU.rows() == m_matV.rows() && "Polar decomposition is only for square matrices");
Scalar x = (m_matU * m_matV.adjoint()).determinant(); // so x has absolute value 1
Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> sv(m_sigma);
sv.coeffRef(0) *= x;
if(scaling) scaling->lazyAssign(m_matU * sv.asDiagonal() * m_matU.adjoint());
if(rotation)
{
MatrixType m(m_matU);
m.col(0) /= x;
rotation->lazyAssign(m * m_matV.adjoint());
}
}
/** \svd_module
* \returns the SVD decomposition of \c *this
*/

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@ -25,7 +25,7 @@
#include "main.h"
#include <Eigen/Geometry>
#include <Eigen/LU>
#include <Eigen/QR>
#include <Eigen/SVD>
template<typename Scalar> void geometry(void)
{
@ -339,10 +339,22 @@ template<typename Scalar> void geometry(void)
t0.translate(v0).rotate(q1);
VERIFY_IS_APPROX(t0.inverse(Isometry), t0.matrix().inverse());
// test extract rotation
// test extract rotation and scaling
t0.setIdentity();
t0.translate(v0).rotate(q1).scale(v1);
VERIFY_IS_APPROX(t0.rotation(Affine) * v1, Matrix3(q1) * v1);
VERIFY_IS_APPROX(t0.rotation() * v1, Matrix3(q1) * v1);
Matrix3 mat_rotation, mat_scaling;
t0.setIdentity();
t0.translate(v0).rotate(q1).scale(v1);
t0.computeRotationScaling(&mat_rotation, &mat_scaling);
VERIFY_IS_APPROX(t0.linear(), mat_rotation * mat_scaling);
VERIFY_IS_APPROX(mat_rotation*mat_rotation.adjoint(), Matrix3::Identity());
VERIFY_IS_APPROX(mat_rotation.determinant(), Scalar(1));
t0.computeScalingRotation(&mat_scaling, &mat_rotation);
VERIFY_IS_APPROX(t0.linear(), mat_scaling * mat_rotation);
VERIFY_IS_APPROX(mat_rotation*mat_rotation.adjoint(), Matrix3::Identity());
VERIFY_IS_APPROX(mat_rotation.determinant(), Scalar(1));
// test casting
Transform<float,3> t1f = t1.template cast<float>();