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-// This file is part of Eigen, a lightweight C++ template library
-// for linear algebra.
-//
-// Copyright (C) 2012, 2013 Chen-Pang He <jdh8@ms63.hinet.net>
-//
-// 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_MATRIX_POWER
-#define EIGEN_MATRIX_POWER
-
-namespace Eigen {
-
-template<typename MatrixType> class MatrixPower;
-
-/**
- * \ingroup MatrixFunctions_Module
- *
- * \brief Proxy for the matrix power of some matrix.
- *
- * \tparam MatrixType type of the base, a matrix.
- *
- * This class holds the arguments to the matrix power until it is
- * assigned or evaluated for some other reason (so the argument
- * should not be changed in the meantime). It is the return type of
- * MatrixPower::operator() and related functions and most of the
- * time this is the only way it is used.
- */
-/* TODO This class is only used by MatrixPower, so it should be nested
- * into MatrixPower, like MatrixPower::ReturnValue. However, my
- * compiler complained about unused template parameter in the
- * following declaration in namespace internal.
- *
- * template<typename MatrixType>
- * struct traits<MatrixPower<MatrixType>::ReturnValue>;
- */
-template<typename MatrixType>
-class MatrixPowerParenthesesReturnValue : public ReturnByValue< MatrixPowerParenthesesReturnValue<MatrixType> >
-{
- public:
- typedef typename MatrixType::RealScalar RealScalar;
- typedef typename MatrixType::Index Index;
-
- /**
- * \brief Constructor.
- *
- * \param[in] pow %MatrixPower storing the base.
- * \param[in] p scalar, the exponent of the matrix power.
- */
- MatrixPowerParenthesesReturnValue(MatrixPower<MatrixType>& pow, RealScalar p) : m_pow(pow), m_p(p)
- { }
-
- /**
- * \brief Compute the matrix power.
- *
- * \param[out] result
- */
- template<typename ResultType>
- inline void evalTo(ResultType& result) const
- { m_pow.compute(result, m_p); }
-
- Index rows() const { return m_pow.rows(); }
- Index cols() const { return m_pow.cols(); }
-
- private:
- MatrixPower<MatrixType>& m_pow;
- const RealScalar m_p;
-};
-
-/**
- * \ingroup MatrixFunctions_Module
- *
- * \brief Class for computing matrix powers.
- *
- * \tparam MatrixType type of the base, expected to be an instantiation
- * of the Matrix class template.
- *
- * This class is capable of computing triangular real/complex matrices
- * raised to a power in the interval \f$ (-1, 1) \f$.
- *
- * \note Currently this class is only used by MatrixPower. One may
- * insist that this be nested into MatrixPower. This class is here to
- * faciliate future development of triangular matrix functions.
- */
-template<typename MatrixType>
-class MatrixPowerAtomic : internal::noncopyable
-{
- private:
- enum {
- RowsAtCompileTime = MatrixType::RowsAtCompileTime,
- MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime
- };
- typedef typename MatrixType::Scalar Scalar;
- typedef typename MatrixType::RealScalar RealScalar;
- typedef std::complex<RealScalar> ComplexScalar;
- typedef typename MatrixType::Index Index;
- typedef Block<MatrixType,Dynamic,Dynamic> ResultType;
-
- const MatrixType& m_A;
- RealScalar m_p;
-
- void computePade(int degree, const MatrixType& IminusT, ResultType& res) const;
- void compute2x2(ResultType& res, RealScalar p) const;
- void computeBig(ResultType& res) const;
- static int getPadeDegree(float normIminusT);
- static int getPadeDegree(double normIminusT);
- static int getPadeDegree(long double normIminusT);
- static ComplexScalar computeSuperDiag(const ComplexScalar&, const ComplexScalar&, RealScalar p);
- static RealScalar computeSuperDiag(RealScalar, RealScalar, RealScalar p);
-
- public:
- /**
- * \brief Constructor.
- *
- * \param[in] T the base of the matrix power.
- * \param[in] p the exponent of the matrix power, should be in
- * \f$ (-1, 1) \f$.
- *
- * The class stores a reference to T, so it should not be changed
- * (or destroyed) before evaluation. Only the upper triangular
- * part of T is read.
- */
- MatrixPowerAtomic(const MatrixType& T, RealScalar p);
-
- /**
- * \brief Compute the matrix power.
- *
- * \param[out] res \f$ A^p \f$ where A and p are specified in the
- * constructor.
- */
- void compute(ResultType& res) const;
-};
-
-template<typename MatrixType>
-MatrixPowerAtomic<MatrixType>::MatrixPowerAtomic(const MatrixType& T, RealScalar p) :
- m_A(T), m_p(p)
-{
- eigen_assert(T.rows() == T.cols());
- eigen_assert(p > -1 && p < 1);
-}
-
-template<typename MatrixType>
-void MatrixPowerAtomic<MatrixType>::compute(ResultType& res) const
-{
- using std::pow;
- switch (m_A.rows()) {
- case 0:
- break;
- case 1:
- res(0,0) = pow(m_A(0,0), m_p);
- break;
- case 2:
- compute2x2(res, m_p);
- break;
- default:
- computeBig(res);
- }
-}
-
-template<typename MatrixType>
-void MatrixPowerAtomic<MatrixType>::computePade(int degree, const MatrixType& IminusT, ResultType& res) const
-{
- int i = 2*degree;
- res = (m_p-degree) / (2*i-2) * IminusT;
-
- for (--i; i; --i) {
- res = (MatrixType::Identity(IminusT.rows(), IminusT.cols()) + res).template triangularView<Upper>()
- .solve((i==1 ? -m_p : i&1 ? (-m_p-i/2)/(2*i) : (m_p-i/2)/(2*i-2)) * IminusT).eval();
- }
- res += MatrixType::Identity(IminusT.rows(), IminusT.cols());
-}
-
-// This function assumes that res has the correct size (see bug 614)
-template<typename MatrixType>
-void MatrixPowerAtomic<MatrixType>::compute2x2(ResultType& res, RealScalar p) const
-{
- using std::abs;
- using std::pow;
- res.coeffRef(0,0) = pow(m_A.coeff(0,0), p);
-
- for (Index i=1; i < m_A.cols(); ++i) {
- res.coeffRef(i,i) = pow(m_A.coeff(i,i), p);
- if (m_A.coeff(i-1,i-1) == m_A.coeff(i,i))
- res.coeffRef(i-1,i) = p * pow(m_A.coeff(i,i), p-1);
- else if (2*abs(m_A.coeff(i-1,i-1)) < abs(m_A.coeff(i,i)) || 2*abs(m_A.coeff(i,i)) < abs(m_A.coeff(i-1,i-1)))
- res.coeffRef(i-1,i) = (res.coeff(i,i)-res.coeff(i-1,i-1)) / (m_A.coeff(i,i)-m_A.coeff(i-1,i-1));
- else
- res.coeffRef(i-1,i) = computeSuperDiag(m_A.coeff(i,i), m_A.coeff(i-1,i-1), p);
- res.coeffRef(i-1,i) *= m_A.coeff(i-1,i);
- }
-}
-
-template<typename MatrixType>
-void MatrixPowerAtomic<MatrixType>::computeBig(ResultType& res) const
-{
- using std::ldexp;
- const int digits = std::numeric_limits<RealScalar>::digits;
- const RealScalar maxNormForPade = digits <= 24? 4.3386528e-1L // single precision
- : digits <= 53? 2.789358995219730e-1L // double precision
- : digits <= 64? 2.4471944416607995472e-1L // extended precision
- : digits <= 106? 1.1016843812851143391275867258512e-1L // double-double
- : 9.134603732914548552537150753385375e-2L; // quadruple precision
- MatrixType IminusT, sqrtT, T = m_A.template triangularView<Upper>();
- RealScalar normIminusT;
- int degree, degree2, numberOfSquareRoots = 0;
- bool hasExtraSquareRoot = false;
-
- for (Index i=0; i < m_A.cols(); ++i)
- eigen_assert(m_A(i,i) != RealScalar(0));
-
- while (true) {
- IminusT = MatrixType::Identity(m_A.rows(), m_A.cols()) - T;
- normIminusT = IminusT.cwiseAbs().colwise().sum().maxCoeff();
- if (normIminusT < maxNormForPade) {
- degree = getPadeDegree(normIminusT);
- degree2 = getPadeDegree(normIminusT/2);
- if (degree - degree2 <= 1 || hasExtraSquareRoot)
- break;
- hasExtraSquareRoot = true;
- }
- matrix_sqrt_triangular(T, sqrtT);
- T = sqrtT.template triangularView<Upper>();
- ++numberOfSquareRoots;
- }
- computePade(degree, IminusT, res);
-
- for (; numberOfSquareRoots; --numberOfSquareRoots) {
- compute2x2(res, ldexp(m_p, -numberOfSquareRoots));
- res = res.template triangularView<Upper>() * res;
- }
- compute2x2(res, m_p);
-}
-
-template<typename MatrixType>
-inline int MatrixPowerAtomic<MatrixType>::getPadeDegree(float normIminusT)
-{
- const float maxNormForPade[] = { 2.8064004e-1f /* degree = 3 */ , 4.3386528e-1f };
- int degree = 3;
- for (; degree <= 4; ++degree)
- if (normIminusT <= maxNormForPade[degree - 3])
- break;
- return degree;
-}
-
-template<typename MatrixType>
-inline int MatrixPowerAtomic<MatrixType>::getPadeDegree(double normIminusT)
-{
- const double maxNormForPade[] = { 1.884160592658218e-2 /* degree = 3 */ , 6.038881904059573e-2, 1.239917516308172e-1,
- 1.999045567181744e-1, 2.789358995219730e-1 };
- int degree = 3;
- for (; degree <= 7; ++degree)
- if (normIminusT <= maxNormForPade[degree - 3])
- break;
- return degree;
-}
-
-template<typename MatrixType>
-inline int MatrixPowerAtomic<MatrixType>::getPadeDegree(long double normIminusT)
-{
-#if LDBL_MANT_DIG == 53
- const int maxPadeDegree = 7;
- const double maxNormForPade[] = { 1.884160592658218e-2L /* degree = 3 */ , 6.038881904059573e-2L, 1.239917516308172e-1L,
- 1.999045567181744e-1L, 2.789358995219730e-1L };
-#elif LDBL_MANT_DIG <= 64
- const int maxPadeDegree = 8;
- const long double maxNormForPade[] = { 6.3854693117491799460e-3L /* degree = 3 */ , 2.6394893435456973676e-2L,
- 6.4216043030404063729e-2L, 1.1701165502926694307e-1L, 1.7904284231268670284e-1L, 2.4471944416607995472e-1L };
-#elif LDBL_MANT_DIG <= 106
- const int maxPadeDegree = 10;
- const double maxNormForPade[] = { 1.0007161601787493236741409687186e-4L /* degree = 3 */ ,
- 1.0007161601787493236741409687186e-3L, 4.7069769360887572939882574746264e-3L, 1.3220386624169159689406653101695e-2L,
- 2.8063482381631737920612944054906e-2L, 4.9625993951953473052385361085058e-2L, 7.7367040706027886224557538328171e-2L,
- 1.1016843812851143391275867258512e-1L };
-#else
- const int maxPadeDegree = 10;
- const double maxNormForPade[] = { 5.524506147036624377378713555116378e-5L /* degree = 3 */ ,
- 6.640600568157479679823602193345995e-4L, 3.227716520106894279249709728084626e-3L,
- 9.619593944683432960546978734646284e-3L, 2.134595382433742403911124458161147e-2L,
- 3.908166513900489428442993794761185e-2L, 6.266780814639442865832535460550138e-2L,
- 9.134603732914548552537150753385375e-2L };
-#endif
- int degree = 3;
- for (; degree <= maxPadeDegree; ++degree)
- if (normIminusT <= maxNormForPade[degree - 3])
- break;
- return degree;
-}
-
-template<typename MatrixType>
-inline typename MatrixPowerAtomic<MatrixType>::ComplexScalar
-MatrixPowerAtomic<MatrixType>::computeSuperDiag(const ComplexScalar& curr, const ComplexScalar& prev, RealScalar p)
-{
- using std::ceil;
- using std::exp;
- using std::log;
- using std::sinh;
-
- ComplexScalar logCurr = log(curr);
- ComplexScalar logPrev = log(prev);
- int unwindingNumber = ceil((numext::imag(logCurr - logPrev) - RealScalar(EIGEN_PI)) / RealScalar(2*EIGEN_PI));
- ComplexScalar w = numext::log1p((curr-prev)/prev)/RealScalar(2) + ComplexScalar(0, EIGEN_PI*unwindingNumber);
- return RealScalar(2) * exp(RealScalar(0.5) * p * (logCurr + logPrev)) * sinh(p * w) / (curr - prev);
-}
-
-template<typename MatrixType>
-inline typename MatrixPowerAtomic<MatrixType>::RealScalar
-MatrixPowerAtomic<MatrixType>::computeSuperDiag(RealScalar curr, RealScalar prev, RealScalar p)
-{
- using std::exp;
- using std::log;
- using std::sinh;
-
- RealScalar w = numext::log1p((curr-prev)/prev)/RealScalar(2);
- return 2 * exp(p * (log(curr) + log(prev)) / 2) * sinh(p * w) / (curr - prev);
-}
-
-/**
- * \ingroup MatrixFunctions_Module
- *
- * \brief Class for computing matrix powers.
- *
- * \tparam MatrixType type of the base, expected to be an instantiation
- * of the Matrix class template.
- *
- * This class is capable of computing real/complex matrices raised to
- * an arbitrary real power. Meanwhile, it saves the result of Schur
- * decomposition if an non-integral power has even been calculated.
- * Therefore, if you want to compute multiple (>= 2) matrix powers
- * for the same matrix, using the class directly is more efficient than
- * calling MatrixBase::pow().
- *
- * Example:
- * \include MatrixPower_optimal.cpp
- * Output: \verbinclude MatrixPower_optimal.out
- */
-template<typename MatrixType>
-class MatrixPower : internal::noncopyable
-{
- private:
- typedef typename MatrixType::Scalar Scalar;
- typedef typename MatrixType::RealScalar RealScalar;
- typedef typename MatrixType::Index Index;
-
- public:
- /**
- * \brief Constructor.
- *
- * \param[in] A the base of the matrix power.
- *
- * The class stores a reference to A, so it should not be changed
- * (or destroyed) before evaluation.
- */
- explicit MatrixPower(const MatrixType& A) :
- m_A(A),
- m_conditionNumber(0),
- m_rank(A.cols()),
- m_nulls(0)
- { eigen_assert(A.rows() == A.cols()); }
-
- /**
- * \brief Returns the matrix power.
- *
- * \param[in] p exponent, a real scalar.
- * \return The expression \f$ A^p \f$, where A is specified in the
- * constructor.
- */
- const MatrixPowerParenthesesReturnValue<MatrixType> operator()(RealScalar p)
- { return MatrixPowerParenthesesReturnValue<MatrixType>(*this, p); }
-
- /**
- * \brief Compute the matrix power.
- *
- * \param[in] p exponent, a real scalar.
- * \param[out] res \f$ A^p \f$ where A is specified in the
- * constructor.
- */
- template<typename ResultType>
- void compute(ResultType& res, RealScalar p);
-
- Index rows() const { return m_A.rows(); }
- Index cols() const { return m_A.cols(); }
-
- private:
- typedef std::complex<RealScalar> ComplexScalar;
- typedef Matrix<ComplexScalar, Dynamic, Dynamic, 0,
- MatrixType::RowsAtCompileTime, MatrixType::ColsAtCompileTime> ComplexMatrix;
-
- /** \brief Reference to the base of matrix power. */
- typename MatrixType::Nested m_A;
-
- /** \brief Temporary storage. */
- MatrixType m_tmp;
-
- /** \brief Store the result of Schur decomposition. */
- ComplexMatrix m_T, m_U;
-
- /** \brief Store fractional power of m_T. */
- ComplexMatrix m_fT;
-
- /**
- * \brief Condition number of m_A.
- *
- * It is initialized as 0 to avoid performing unnecessary Schur
- * decomposition, which is the bottleneck.
- */
- RealScalar m_conditionNumber;
-
- /** \brief Rank of m_A. */
- Index m_rank;
-
- /** \brief Rank deficiency of m_A. */
- Index m_nulls;
-
- /**
- * \brief Split p into integral part and fractional part.
- *
- * \param[in] p The exponent.
- * \param[out] p The fractional part ranging in \f$ (-1, 1) \f$.
- * \param[out] intpart The integral part.
- *
- * Only if the fractional part is nonzero, it calls initialize().
- */
- void split(RealScalar& p, RealScalar& intpart);
-
- /** \brief Perform Schur decomposition for fractional power. */
- void initialize();
-
- template<typename ResultType>
- void computeIntPower(ResultType& res, RealScalar p);
-
- template<typename ResultType>
- void computeFracPower(ResultType& res, RealScalar p);
-
- template<int Rows, int Cols, int Options, int MaxRows, int MaxCols>
- static void revertSchur(
- Matrix<ComplexScalar, Rows, Cols, Options, MaxRows, MaxCols>& res,
- const ComplexMatrix& T,
- const ComplexMatrix& U);
-
- template<int Rows, int Cols, int Options, int MaxRows, int MaxCols>
- static void revertSchur(
- Matrix<RealScalar, Rows, Cols, Options, MaxRows, MaxCols>& res,
- const ComplexMatrix& T,
- const ComplexMatrix& U);
-};
-
-template<typename MatrixType>
-template<typename ResultType>
-void MatrixPower<MatrixType>::compute(ResultType& res, RealScalar p)
-{
- using std::pow;
- switch (cols()) {
- case 0:
- break;
- case 1:
- res(0,0) = pow(m_A.coeff(0,0), p);
- break;
- default:
- RealScalar intpart;
- split(p, intpart);
-
- res = MatrixType::Identity(rows(), cols());
- computeIntPower(res, intpart);
- if (p) computeFracPower(res, p);
- }
-}
-
-template<typename MatrixType>
-void MatrixPower<MatrixType>::split(RealScalar& p, RealScalar& intpart)
-{
- using std::floor;
- using std::pow;
-
- intpart = floor(p);
- p -= intpart;
-
- // Perform Schur decomposition if it is not yet performed and the power is
- // not an integer.
- if (!m_conditionNumber && p)
- initialize();
-
- // Choose the more stable of intpart = floor(p) and intpart = ceil(p).
- if (p > RealScalar(0.5) && p > (1-p) * pow(m_conditionNumber, p)) {
- --p;
- ++intpart;
- }
-}
-
-template<typename MatrixType>
-void MatrixPower<MatrixType>::initialize()
-{
- const ComplexSchur<MatrixType> schurOfA(m_A);
- JacobiRotation<ComplexScalar> rot;
- ComplexScalar eigenvalue;
-
- m_fT.resizeLike(m_A);
- m_T = schurOfA.matrixT();
- m_U = schurOfA.matrixU();
- m_conditionNumber = m_T.diagonal().array().abs().maxCoeff() / m_T.diagonal().array().abs().minCoeff();
-
- // Move zero eigenvalues to the bottom right corner.
- for (Index i = cols()-1; i>=0; --i) {
- if (m_rank <= 2)
- return;
- if (m_T.coeff(i,i) == RealScalar(0)) {
- for (Index j=i+1; j < m_rank; ++j) {
- eigenvalue = m_T.coeff(j,j);
- rot.makeGivens(m_T.coeff(j-1,j), eigenvalue);
- m_T.applyOnTheRight(j-1, j, rot);
- m_T.applyOnTheLeft(j-1, j, rot.adjoint());
- m_T.coeffRef(j-1,j-1) = eigenvalue;
- m_T.coeffRef(j,j) = RealScalar(0);
- m_U.applyOnTheRight(j-1, j, rot);
- }
- --m_rank;
- }
- }
-
- m_nulls = rows() - m_rank;
- if (m_nulls) {
- eigen_assert(m_T.bottomRightCorner(m_nulls, m_nulls).isZero()
- && "Base of matrix power should be invertible or with a semisimple zero eigenvalue.");
- m_fT.bottomRows(m_nulls).fill(RealScalar(0));
- }
-}
-
-template<typename MatrixType>
-template<typename ResultType>
-void MatrixPower<MatrixType>::computeIntPower(ResultType& res, RealScalar p)
-{
- using std::abs;
- using std::fmod;
- RealScalar pp = abs(p);
-
- if (p<0)
- m_tmp = m_A.inverse();
- else
- m_tmp = m_A;
-
- while (true) {
- if (fmod(pp, 2) >= 1)
- res = m_tmp * res;
- pp /= 2;
- if (pp < 1)
- break;
- m_tmp *= m_tmp;
- }
-}
-
-template<typename MatrixType>
-template<typename ResultType>
-void MatrixPower<MatrixType>::computeFracPower(ResultType& res, RealScalar p)
-{
- Block<ComplexMatrix,Dynamic,Dynamic> blockTp(m_fT, 0, 0, m_rank, m_rank);
- eigen_assert(m_conditionNumber);
- eigen_assert(m_rank + m_nulls == rows());
-
- MatrixPowerAtomic<ComplexMatrix>(m_T.topLeftCorner(m_rank, m_rank), p).compute(blockTp);
- if (m_nulls) {
- m_fT.topRightCorner(m_rank, m_nulls) = m_T.topLeftCorner(m_rank, m_rank).template triangularView<Upper>()
- .solve(blockTp * m_T.topRightCorner(m_rank, m_nulls));
- }
- revertSchur(m_tmp, m_fT, m_U);
- res = m_tmp * res;
-}
-
-template<typename MatrixType>
-template<int Rows, int Cols, int Options, int MaxRows, int MaxCols>
-inline void MatrixPower<MatrixType>::revertSchur(
- Matrix<ComplexScalar, Rows, Cols, Options, MaxRows, MaxCols>& res,
- const ComplexMatrix& T,
- const ComplexMatrix& U)
-{ res.noalias() = U * (T.template triangularView<Upper>() * U.adjoint()); }
-
-template<typename MatrixType>
-template<int Rows, int Cols, int Options, int MaxRows, int MaxCols>
-inline void MatrixPower<MatrixType>::revertSchur(
- Matrix<RealScalar, Rows, Cols, Options, MaxRows, MaxCols>& res,
- const ComplexMatrix& T,
- const ComplexMatrix& U)
-{ res.noalias() = (U * (T.template triangularView<Upper>() * U.adjoint())).real(); }
-
-/**
- * \ingroup MatrixFunctions_Module
- *
- * \brief Proxy for the matrix power of some matrix (expression).
- *
- * \tparam Derived type of the base, a matrix (expression).
- *
- * This class holds the arguments to the matrix power until it is
- * assigned or evaluated for some other reason (so the argument
- * should not be changed in the meantime). It is the return type of
- * MatrixBase::pow() and related functions and most of the
- * time this is the only way it is used.
- */
-template<typename Derived>
-class MatrixPowerReturnValue : public ReturnByValue< MatrixPowerReturnValue<Derived> >
-{
- public:
- typedef typename Derived::PlainObject PlainObject;
- typedef typename Derived::RealScalar RealScalar;
- typedef typename Derived::Index Index;
-
- /**
- * \brief Constructor.
- *
- * \param[in] A %Matrix (expression), the base of the matrix power.
- * \param[in] p real scalar, the exponent of the matrix power.
- */
- MatrixPowerReturnValue(const Derived& A, RealScalar p) : m_A(A), m_p(p)
- { }
-
- /**
- * \brief Compute the matrix power.
- *
- * \param[out] result \f$ A^p \f$ where \p A and \p p are as in the
- * constructor.
- */
- template<typename ResultType>
- inline void evalTo(ResultType& result) const
- { MatrixPower<PlainObject>(m_A.eval()).compute(result, m_p); }
-
- Index rows() const { return m_A.rows(); }
- Index cols() const { return m_A.cols(); }
-
- private:
- const Derived& m_A;
- const RealScalar m_p;
-};
-
-/**
- * \ingroup MatrixFunctions_Module
- *
- * \brief Proxy for the matrix power of some matrix (expression).
- *
- * \tparam Derived type of the base, a matrix (expression).
- *
- * This class holds the arguments to the matrix power until it is
- * assigned or evaluated for some other reason (so the argument
- * should not be changed in the meantime). It is the return type of
- * MatrixBase::pow() and related functions and most of the
- * time this is the only way it is used.
- */
-template<typename Derived>
-class MatrixComplexPowerReturnValue : public ReturnByValue< MatrixComplexPowerReturnValue<Derived> >
-{
- public:
- typedef typename Derived::PlainObject PlainObject;
- typedef typename std::complex<typename Derived::RealScalar> ComplexScalar;
- typedef typename Derived::Index Index;
-
- /**
- * \brief Constructor.
- *
- * \param[in] A %Matrix (expression), the base of the matrix power.
- * \param[in] p complex scalar, the exponent of the matrix power.
- */
- MatrixComplexPowerReturnValue(const Derived& A, const ComplexScalar& p) : m_A(A), m_p(p)
- { }
-
- /**
- * \brief Compute the matrix power.
- *
- * Because \p p is complex, \f$ A^p \f$ is simply evaluated as \f$
- * \exp(p \log(A)) \f$.
- *
- * \param[out] result \f$ A^p \f$ where \p A and \p p are as in the
- * constructor.
- */
- template<typename ResultType>
- inline void evalTo(ResultType& result) const
- { result = (m_p * m_A.log()).exp(); }
-
- Index rows() const { return m_A.rows(); }
- Index cols() const { return m_A.cols(); }
-
- private:
- const Derived& m_A;
- const ComplexScalar m_p;
-};
-
-namespace internal {
-
-template<typename MatrixPowerType>
-struct traits< MatrixPowerParenthesesReturnValue<MatrixPowerType> >
-{ typedef typename MatrixPowerType::PlainObject ReturnType; };
-
-template<typename Derived>
-struct traits< MatrixPowerReturnValue<Derived> >
-{ typedef typename Derived::PlainObject ReturnType; };
-
-template<typename Derived>
-struct traits< MatrixComplexPowerReturnValue<Derived> >
-{ typedef typename Derived::PlainObject ReturnType; };
-
-}
-
-template<typename Derived>
-const MatrixPowerReturnValue<Derived> MatrixBase<Derived>::pow(const RealScalar& p) const
-{ return MatrixPowerReturnValue<Derived>(derived(), p); }
-
-template<typename Derived>
-const MatrixComplexPowerReturnValue<Derived> MatrixBase<Derived>::pow(const std::complex<RealScalar>& p) const
-{ return MatrixComplexPowerReturnValue<Derived>(derived(), p); }
-
-} // namespace Eigen
-
-#endif // EIGEN_MATRIX_POWER