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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// 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
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#ifndef EIGEN_JACOBISVD_H
#define EIGEN_JACOBISVD_H
// forward declarations (needed by ICC)
// the empty bodies are required by VC
template<typename MatrixType, unsigned int Options, bool IsComplex = NumTraits<typename MatrixType::Scalar>::IsComplex>
struct ei_svd_precondition_2x2_block_to_be_real {};
template<typename MatrixType, unsigned int Options,
bool PossiblyMoreRowsThanCols = (Options & AtLeastAsManyColsAsRows) == 0
&& (MatrixType::RowsAtCompileTime==Dynamic
|| (MatrixType::RowsAtCompileTime>MatrixType::ColsAtCompileTime))>
struct ei_svd_precondition_if_more_rows_than_cols;
template<typename MatrixType, unsigned int Options,
bool PossiblyMoreColsThanRows = (Options & AtLeastAsManyRowsAsCols) == 0
&& (MatrixType::ColsAtCompileTime==Dynamic
|| (MatrixType::ColsAtCompileTime>MatrixType::RowsAtCompileTime))>
struct ei_svd_precondition_if_more_cols_than_rows;
/** \ingroup SVD_Module
* \nonstableyet
*
* \class JacobiSVD
*
* \brief Jacobi SVD decomposition of a square matrix
*
* \param MatrixType the type of the matrix of which we are computing the SVD decomposition
* \param Options a bit field of flags offering the following options: \c SkipU and \c SkipV allow to skip the computation of
* the unitaries \a U and \a V respectively; \c AtLeastAsManyRowsAsCols and \c AtLeastAsManyRowsAsCols allows
* to hint the compiler to only generate the corresponding code paths; \c Square is equivantent to the combination of
* the latter two bits and is useful when you know that the matrix is square. Note that when this information can
* be automatically deduced from the matrix type (e.g. a Matrix3f is always square), Eigen does it for you.
*
* \sa MatrixBase::jacobiSvd()
*/
template<typename MatrixType, unsigned int Options> class JacobiSVD
{
private:
typedef typename MatrixType::Scalar Scalar;
typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
enum {
ComputeU = (Options & SkipU) == 0,
ComputeV = (Options & SkipV) == 0,
RowsAtCompileTime = MatrixType::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::ColsAtCompileTime,
DiagSizeAtCompileTime = EIGEN_SIZE_MIN(RowsAtCompileTime,ColsAtCompileTime),
MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime,
MaxDiagSizeAtCompileTime = EIGEN_SIZE_MIN(MaxRowsAtCompileTime,MaxColsAtCompileTime),
MatrixOptions = MatrixType::Options
};
typedef Matrix<Scalar, Dynamic, Dynamic, MatrixOptions> DummyMatrixType;
typedef typename ei_meta_if<ComputeU,
Matrix<Scalar, RowsAtCompileTime, RowsAtCompileTime,
MatrixOptions, MaxRowsAtCompileTime, MaxRowsAtCompileTime>,
DummyMatrixType>::ret MatrixUType;
typedef typename ei_meta_if<ComputeV,
Matrix<Scalar, ColsAtCompileTime, ColsAtCompileTime,
MatrixOptions, MaxColsAtCompileTime, MaxColsAtCompileTime>,
DummyMatrixType>::ret MatrixVType;
typedef typename ei_plain_diag_type<MatrixType, RealScalar>::type SingularValuesType;
typedef typename ei_plain_row_type<MatrixType>::type RowType;
typedef typename ei_plain_col_type<MatrixType>::type ColType;
typedef Matrix<Scalar, DiagSizeAtCompileTime, DiagSizeAtCompileTime,
MatrixOptions, MaxDiagSizeAtCompileTime, MaxDiagSizeAtCompileTime>
WorkMatrixType;
public:
/** \brief Default Constructor.
*
* The default constructor is useful in cases in which the user intends to
* perform decompositions via JacobiSVD::compute(const MatrixType&).
*/
JacobiSVD() : m_isInitialized(false) {}
/** \brief Default Constructor with memory preallocation
*
* Like the default constructor but with preallocation of the internal data
* according to the specified problem \a size.
* \sa JacobiSVD()
*/
JacobiSVD(int rows, int cols) : m_matrixU(rows, rows),
m_matrixV(cols, cols),
m_singularValues(std::min(rows, cols)),
m_workMatrix(rows, cols),
m_isInitialized(false) {}
JacobiSVD(const MatrixType& matrix) : m_matrixU(matrix.rows(), matrix.rows()),
m_matrixV(matrix.cols(), matrix.cols()),
m_singularValues(),
m_workMatrix(),
m_isInitialized(false)
{
const int minSize = std::min(matrix.rows(), matrix.cols());
m_singularValues.resize(minSize);
m_workMatrix.resize(minSize, minSize);
compute(matrix);
}
JacobiSVD& compute(const MatrixType& matrix);
const MatrixUType& matrixU() const
{
ei_assert(m_isInitialized && "JacobiSVD is not initialized.");
return m_matrixU;
}
const SingularValuesType& singularValues() const
{
ei_assert(m_isInitialized && "JacobiSVD is not initialized.");
return m_singularValues;
}
const MatrixVType& matrixV() const
{
ei_assert(m_isInitialized && "JacobiSVD is not initialized.");
return m_matrixV;
}
protected:
MatrixUType m_matrixU;
MatrixVType m_matrixV;
SingularValuesType m_singularValues;
WorkMatrixType m_workMatrix;
bool m_isInitialized;
template<typename _MatrixType, unsigned int _Options, bool _IsComplex>
friend struct ei_svd_precondition_2x2_block_to_be_real;
template<typename _MatrixType, unsigned int _Options, bool _PossiblyMoreRowsThanCols>
friend struct ei_svd_precondition_if_more_rows_than_cols;
template<typename _MatrixType, unsigned int _Options, bool _PossiblyMoreRowsThanCols>
friend struct ei_svd_precondition_if_more_cols_than_rows;
};
template<typename MatrixType, unsigned int Options>
struct ei_svd_precondition_2x2_block_to_be_real<MatrixType, Options, false>
{
typedef JacobiSVD<MatrixType, Options> SVD;
static void run(typename SVD::WorkMatrixType&, JacobiSVD<MatrixType, Options>&, int, int) {}
};
template<typename MatrixType, unsigned int Options>
struct ei_svd_precondition_2x2_block_to_be_real<MatrixType, Options, true>
{
typedef JacobiSVD<MatrixType, Options> SVD;
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::RealScalar RealScalar;
enum { ComputeU = SVD::ComputeU, ComputeV = SVD::ComputeV };
static void run(typename SVD::WorkMatrixType& work_matrix, JacobiSVD<MatrixType, Options>& svd, int p, int q)
{
Scalar z;
PlanarRotation<Scalar> rot;
RealScalar n = ei_sqrt(ei_abs2(work_matrix.coeff(p,p)) + ei_abs2(work_matrix.coeff(q,p)));
if(n==0)
{
z = ei_abs(work_matrix.coeff(p,q)) / work_matrix.coeff(p,q);
work_matrix.row(p) *= z;
if(ComputeU) svd.m_matrixU.col(p) *= ei_conj(z);
z = ei_abs(work_matrix.coeff(q,q)) / work_matrix.coeff(q,q);
work_matrix.row(q) *= z;
if(ComputeU) svd.m_matrixU.col(q) *= ei_conj(z);
}
else
{
rot.c() = ei_conj(work_matrix.coeff(p,p)) / n;
rot.s() = work_matrix.coeff(q,p) / n;
work_matrix.applyOnTheLeft(p,q,rot);
if(ComputeU) svd.m_matrixU.applyOnTheRight(p,q,rot.adjoint());
if(work_matrix.coeff(p,q) != Scalar(0))
{
Scalar z = ei_abs(work_matrix.coeff(p,q)) / work_matrix.coeff(p,q);
work_matrix.col(q) *= z;
if(ComputeV) svd.m_matrixV.col(q) *= z;
}
if(work_matrix.coeff(q,q) != Scalar(0))
{
z = ei_abs(work_matrix.coeff(q,q)) / work_matrix.coeff(q,q);
work_matrix.row(q) *= z;
if(ComputeU) svd.m_matrixU.col(q) *= ei_conj(z);
}
}
}
};
template<typename MatrixType, typename RealScalar>
void ei_real_2x2_jacobi_svd(const MatrixType& matrix, int p, int q,
PlanarRotation<RealScalar> *j_left,
PlanarRotation<RealScalar> *j_right)
{
Matrix<RealScalar,2,2> m;
m << ei_real(matrix.coeff(p,p)), ei_real(matrix.coeff(p,q)),
ei_real(matrix.coeff(q,p)), ei_real(matrix.coeff(q,q));
PlanarRotation<RealScalar> rot1;
RealScalar t = m.coeff(0,0) + m.coeff(1,1);
RealScalar d = m.coeff(1,0) - m.coeff(0,1);
if(t == RealScalar(0))
{
rot1.c() = 0;
rot1.s() = d > 0 ? 1 : -1;
}
else
{
RealScalar u = d / t;
rot1.c() = RealScalar(1) / ei_sqrt(1 + ei_abs2(u));
rot1.s() = rot1.c() * u;
}
m.applyOnTheLeft(0,1,rot1);
j_right->makeJacobi(m,0,1);
*j_left = rot1 * j_right->transpose();
}
template<typename MatrixType, unsigned int Options, bool PossiblyMoreRowsThanCols>
struct ei_svd_precondition_if_more_rows_than_cols
{
typedef JacobiSVD<MatrixType, Options> SVD;
static bool run(const MatrixType&, typename SVD::WorkMatrixType&, JacobiSVD<MatrixType, Options>&) { return false; }
};
template<typename MatrixType, unsigned int Options>
struct ei_svd_precondition_if_more_rows_than_cols<MatrixType, Options, true>
{
typedef JacobiSVD<MatrixType, Options> SVD;
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::RealScalar RealScalar;
enum { ComputeU = SVD::ComputeU, ComputeV = SVD::ComputeV };
static bool run(const MatrixType& matrix, typename SVD::WorkMatrixType& work_matrix, SVD& svd)
{
int rows = matrix.rows();
int cols = matrix.cols();
int diagSize = cols;
if(rows > cols)
{
FullPivHouseholderQR<MatrixType> qr(matrix);
work_matrix = qr.matrixQR().block(0,0,diagSize,diagSize).template triangularView<Upper>();
if(ComputeU) svd.m_matrixU = qr.matrixQ();
if(ComputeV) svd.m_matrixV = qr.colsPermutation();
return true;
}
else return false;
}
};
template<typename MatrixType, unsigned int Options, bool PossiblyMoreColsThanRows>
struct ei_svd_precondition_if_more_cols_than_rows
{
typedef JacobiSVD<MatrixType, Options> SVD;
static bool run(const MatrixType&, typename SVD::WorkMatrixType&, JacobiSVD<MatrixType, Options>&) { return false; }
};
template<typename MatrixType, unsigned int Options>
struct ei_svd_precondition_if_more_cols_than_rows<MatrixType, Options, true>
{
typedef JacobiSVD<MatrixType, Options> SVD;
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::RealScalar RealScalar;
enum {
ComputeU = SVD::ComputeU,
ComputeV = SVD::ComputeV,
RowsAtCompileTime = SVD::RowsAtCompileTime,
ColsAtCompileTime = SVD::ColsAtCompileTime,
MaxRowsAtCompileTime = SVD::MaxRowsAtCompileTime,
MaxColsAtCompileTime = SVD::MaxColsAtCompileTime,
MatrixOptions = SVD::MatrixOptions
};
static bool run(const MatrixType& matrix, typename SVD::WorkMatrixType& work_matrix, SVD& svd)
{
int rows = matrix.rows();
int cols = matrix.cols();
int diagSize = rows;
if(cols > rows)
{
typedef Matrix<Scalar,ColsAtCompileTime,RowsAtCompileTime,
MatrixOptions,MaxColsAtCompileTime,MaxRowsAtCompileTime>
TransposeTypeWithSameStorageOrder;
FullPivHouseholderQR<TransposeTypeWithSameStorageOrder> qr(matrix.adjoint());
work_matrix = qr.matrixQR().block(0,0,diagSize,diagSize).template triangularView<Upper>().adjoint();
if(ComputeV) svd.m_matrixV = qr.matrixQ();
if(ComputeU) svd.m_matrixU = qr.colsPermutation();
return true;
}
else return false;
}
};
template<typename MatrixType, unsigned int Options>
JacobiSVD<MatrixType, Options>& JacobiSVD<MatrixType, Options>::compute(const MatrixType& matrix)
{
int rows = matrix.rows();
int cols = matrix.cols();
int diagSize = std::min(rows, cols);
m_singularValues.resize(diagSize);
const RealScalar precision = 2 * NumTraits<Scalar>::epsilon();
if(!ei_svd_precondition_if_more_rows_than_cols<MatrixType, Options>::run(matrix, m_workMatrix, *this)
&& !ei_svd_precondition_if_more_cols_than_rows<MatrixType, Options>::run(matrix, m_workMatrix, *this))
{
m_workMatrix = matrix.block(0,0,diagSize,diagSize);
if(ComputeU) m_matrixU.setIdentity(rows,rows);
if(ComputeV) m_matrixV.setIdentity(cols,cols);
}
bool finished = false;
while(!finished)
{
finished = true;
for(int p = 1; p < diagSize; ++p)
{
for(int q = 0; q < p; ++q)
{
if(std::max(ei_abs(m_workMatrix.coeff(p,q)),ei_abs(m_workMatrix.coeff(q,p)))
> std::max(ei_abs(m_workMatrix.coeff(p,p)),ei_abs(m_workMatrix.coeff(q,q)))*precision)
{
finished = false;
ei_svd_precondition_2x2_block_to_be_real<MatrixType, Options>::run(m_workMatrix, *this, p, q);
PlanarRotation<RealScalar> j_left, j_right;
ei_real_2x2_jacobi_svd(m_workMatrix, p, q, &j_left, &j_right);
m_workMatrix.applyOnTheLeft(p,q,j_left);
if(ComputeU) m_matrixU.applyOnTheRight(p,q,j_left.transpose());
m_workMatrix.applyOnTheRight(p,q,j_right);
if(ComputeV) m_matrixV.applyOnTheRight(p,q,j_right);
}
}
}
}
for(int i = 0; i < diagSize; ++i)
{
RealScalar a = ei_abs(m_workMatrix.coeff(i,i));
m_singularValues.coeffRef(i) = a;
if(ComputeU && (a!=RealScalar(0))) m_matrixU.col(i) *= m_workMatrix.coeff(i,i)/a;
}
for(int i = 0; i < diagSize; i++)
{
int pos;
m_singularValues.tail(diagSize-i).maxCoeff(&pos);
if(pos)
{
pos += i;
std::swap(m_singularValues.coeffRef(i), m_singularValues.coeffRef(pos));
if(ComputeU) m_matrixU.col(pos).swap(m_matrixU.col(i));
if(ComputeV) m_matrixV.col(pos).swap(m_matrixV.col(i));
}
}
m_isInitialized = true;
return *this;
}
#endif // EIGEN_JACOBISVD_H