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Document on complex matrix power.

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Chen-Pang He 2013-07-13 22:12:09 +08:00
parent 738d75d3eb
commit 3c423ccfe2
1 changed files with 29 additions and 1 deletions
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30
unsupported/Eigen/src/MatrixFunctions/MatrixPower.h
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@ -513,7 +513,7 @@ class MatrixPowerReturnValue : public ReturnByValue< MatrixPowerReturnValue<Deri
* \brief Constructor. * \brief Constructor.
* *
* \param[in] A %Matrix (expression), the base of the matrix power. * \param[in] A %Matrix (expression), the base of the matrix power.
* \param[in] p scalar, the exponent 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) MatrixPowerReturnValue(const Derived& A, RealScalar p) : m_A(A), m_p(p)
{ } { }
@ -536,6 +536,19 @@ class MatrixPowerReturnValue : public ReturnByValue< MatrixPowerReturnValue<Deri
const RealScalar m_p; 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> template<typename Derived>
class MatrixComplexPowerReturnValue : public ReturnByValue< MatrixComplexPowerReturnValue<Derived> > class MatrixComplexPowerReturnValue : public ReturnByValue< MatrixComplexPowerReturnValue<Derived> >
{ {
@ -544,9 +557,24 @@ class MatrixComplexPowerReturnValue : public ReturnByValue< MatrixComplexPowerRe
typedef typename std::complex<typename Derived::RealScalar> ComplexScalar; typedef typename std::complex<typename Derived::RealScalar> ComplexScalar;
typedef typename Derived::Index Index; 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) 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> template<typename ResultType>
inline void evalTo(ResultType& res) const inline void evalTo(ResultType& res) const
{ res = (m_p * m_A.log()).exp(); } { res = (m_p * m_A.log()).exp(); }