Hi,

I have a user defined function abs( MatrixBase< D > const& m ) which calculates the column-wise absolute value of the matrix:

Code: Select all

template< typename D >
inline const
typename Eigen::CwiseUnaryOp<
    typename Eigen::internal::scalar_abs_op<
        typename Eigen::internal::traits< D >::Scalar > ,
        const D >
abs( const Eigen::MatrixBase< D > &m ) {
    return m.cwiseAbs();
}


Is there a way to overload this function for matrixes and expressions consisting of std::complex<>? In case of a matrix of complex this method should return an expression with complex values not doubles.

Not tested, but that should do the job:

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inline const
typename Eigen::CwiseUnaryOp<
   Eigen::internal::scalar_abs_op<typename D::Scalar> ,
   const D >::CastXpr<typename D::Scalar >::Type
abs( const Eigen::MatrixBase<D> &m ) {
    return m.cwiseAbs().template cast<typename D::Scalar>();
}


If D::Scalar is real, then the cast operation is a no-op.

ggael wrote:Not tested, but that should do the job:

Hmm, no this is not working. I don't even see CastXpr in eigen. Which Eigen are you referring to. My own is 3.2.2. Maybe this one is to old?

right, it is only defined in the devel branch. in the meantime the returned type of cast is:

template<typename NewType>
typename internal::cast_return_type<Derived,const CwiseUnaryOp<internal::scalar_cast_op<typename internal::traits<Derived>::Scalar, NewType>, const Derived> >::type