eigen/Eigen/src/Core/CwiseUnaryOp.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
//
// 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_CWISE_UNARY_OP_H
#define EIGEN_CWISE_UNARY_OP_H

/** \class CwiseUnaryOp
  *
  * \brief Generic expression of a coefficient-wise unary operator of a matrix or a vector
  *
  * \param UnaryOp template functor implementing the operator
  * \param MatrixType the type of the matrix we are applying the unary operator
  *
  * This class represents an expression of a generic unary operator of a matrix or a vector.
  * It is the return type of the unary operator-, of a matrix or a vector, and most
  * of the time this is the only way it is used.
  *
  * \sa class CwiseBinaryOp
  */
template<typename UnaryOp, typename MatrixType>
struct ei_traits<CwiseUnaryOp<UnaryOp, MatrixType> >
{
  typedef typename ei_result_of<
                     UnaryOp(typename MatrixType::Scalar)
                   >::type Scalar;
  enum {
    RowsAtCompileTime = MatrixType::RowsAtCompileTime,
    ColsAtCompileTime = MatrixType::ColsAtCompileTime,
    MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime,
    MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime
  };
};

template<typename UnaryOp, typename MatrixType>
class CwiseUnaryOp : ei_no_assignment_operator,
  public MatrixBase<CwiseUnaryOp<UnaryOp, MatrixType> >
{
  public:

    EIGEN_GENERIC_PUBLIC_INTERFACE(CwiseUnaryOp)

    typedef typename MatrixType::AsArg MatRef;

    CwiseUnaryOp(const MatRef& mat, const UnaryOp& func = UnaryOp()) : m_matrix(mat), m_functor(func) {}

  private:

    const CwiseUnaryOp& _asArg() const { return *this; }
    int _rows() const { return m_matrix.rows(); }
    int _cols() const { return m_matrix.cols(); }

    Scalar _coeff(int row, int col) const
    {
      return m_functor(m_matrix.coeff(row, col));
    }

  protected:
    const MatRef m_matrix;
    const UnaryOp m_functor;
};

/** \internal
  * \brief Template functor to compute the opposite of a scalar
  *
  * \sa class CwiseUnaryOp, MatrixBase::operator-
  */
struct ei_scalar_opposite_op EIGEN_EMPTY_STRUCT {
  template<typename Scalar> Scalar operator() (const Scalar& a) const { return -a; }
};

/** \internal
  * \brief Template functor to compute the absolute value of a scalar
  *
  * \sa class CwiseUnaryOp, MatrixBase::cwiseAbs
  */
struct ei_scalar_abs_op EIGEN_EMPTY_STRUCT {
  template<typename Scalar> Scalar operator() (const Scalar& a) const { return ei_abs(a); }
};


/** \returns an expression of the opposite of \c *this
  */
template<typename Derived>
const CwiseUnaryOp<ei_scalar_opposite_op,Derived>
MatrixBase<Derived>::operator-() const
{
  return CwiseUnaryOp<ei_scalar_opposite_op,Derived>(asArg());
}

/** \returns an expression of the opposite of \c *this
  */
template<typename Derived>
const CwiseUnaryOp<ei_scalar_abs_op,Derived>
MatrixBase<Derived>::cwiseAbs() const
{
  return CwiseUnaryOp<ei_scalar_abs_op,Derived>(asArg());
}


/** \returns an expression of a custom coefficient-wise unary operator \a func of *this
  *
  * The template parameter \a CustomUnaryOp is the type of the functor
  * of the custom unary operator.
  *
  * Here is an example:
  * \include class_CwiseUnaryOp.cpp
  *
  * \sa class CwiseUnaryOp, class CwiseBinarOp, MatrixBase::operator-, MatrixBase::cwiseAbs
  */
template<typename Derived>
template<typename CustomUnaryOp>
const CwiseUnaryOp<CustomUnaryOp, Derived>
MatrixBase<Derived>::cwise(const CustomUnaryOp& func) const
{
  return CwiseUnaryOp<CustomUnaryOp, Derived>(asArg(), func);
}


/** \internal
  * \brief Template functor to compute the conjugate of a complex value
  *
  * \sa class CwiseUnaryOp, MatrixBase::conjugate()
  */
struct ei_scalar_conjugate_op EIGEN_EMPTY_STRUCT {
    template<typename Scalar> Scalar operator() (const Scalar& a) const { return ei_conj(a); }
};

/** \returns an expression of the complex conjugate of *this.
  *
  * \sa adjoint() */
template<typename Derived>
const CwiseUnaryOp<ei_scalar_conjugate_op, Derived>
MatrixBase<Derived>::conjugate() const
{
  return CwiseUnaryOp<ei_scalar_conjugate_op, Derived>(asArg());
}

/** \internal
  * \brief Template functor to cast a scalar to another type
  *
  * \sa class CwiseUnaryOp, MatrixBase::cast()
  */
template<typename NewType>
struct ei_scalar_cast_op EIGEN_EMPTY_STRUCT {
    typedef NewType result_type;
    template<typename Scalar> NewType operator() (const Scalar& a) const { return static_cast<NewType>(a); }
};

/** \returns an expression of *this with the \a Scalar type casted to
  * \a NewScalar.
  *
  * The template parameter \a NewScalar is the type we are casting the scalars to.
  *
  * Example: \include MatrixBase_cast.cpp
  * Output: \verbinclude MatrixBase_cast.out
  *
  * \sa class CwiseUnaryOp, class ei_scalar_cast_op
  */
template<typename Derived>
template<typename NewType>
const CwiseUnaryOp<ei_scalar_cast_op<NewType>, Derived>
MatrixBase<Derived>::cast() const
{
  return CwiseUnaryOp<ei_scalar_cast_op<NewType>, Derived>(asArg());
}

/** \internal
  * \brief Template functor to multiply a scalar by a fixed other one
  *
  * \sa class CwiseUnaryOp, MatrixBase::operator*, MatrixBase::operator/
  */
template<typename Scalar>
struct ei_scalar_multiple_op {
    ei_scalar_multiple_op(const Scalar& other) : m_other(other) {}
    Scalar operator() (const Scalar& a) const { return a * m_other; }
    const Scalar m_other;
};

/** \relates MatrixBase \sa class ei_scalar_multiple_op */
template<typename Derived>
const CwiseUnaryOp<ei_scalar_multiple_op<typename ei_traits<Derived>::Scalar>, Derived>
MatrixBase<Derived>::operator*(const Scalar& scalar) const
{
  return CwiseUnaryOp<ei_scalar_multiple_op<Scalar>, Derived>(asArg(), ei_scalar_multiple_op<Scalar>(scalar));
}

/** \relates MatrixBase \sa class ei_scalar_multiple_op */
template<typename Derived>
const CwiseUnaryOp<ei_scalar_multiple_op<typename ei_traits<Derived>::Scalar>, Derived>
MatrixBase<Derived>::operator/(const Scalar& scalar) const
{
  assert(NumTraits<Scalar>::HasFloatingPoint);
  return CwiseUnaryOp<ei_scalar_multiple_op<Scalar>, Derived>
    (asArg(), ei_scalar_multiple_op<Scalar>(static_cast<Scalar>(1) / scalar));
}

/** \sa ei_scalar_multiple_op */
template<typename Derived>
Derived&
MatrixBase<Derived>::operator*=(const Scalar& other)
{
  return *this = *this * other;
}

/** \sa ei_scalar_multiple_op */
template<typename Derived>
Derived&
MatrixBase<Derived>::operator/=(const Scalar& other)
{
  return *this = *this / other;
}

#endif // EIGEN_CWISE_UNARY_OP_H