Function leftCols

python/include/Eigen/src/plugins/BlockMethods.h:630–634

///
template<int N>
EIGEN_DEVICE_FUNC
inline typename NColsBlockXpr<N>::Type leftCols(Index n = N)
{
  return typename NColsBlockXpr<N>::Type(derived(), 0, 0, rows(), n);
}

/// This is the const version of leftCols<int>().
template<int N>