Function value

include/Eigen/Eigen/src/SparseCore/SparseBlock.h:524–524

  inline Index col()    const { return XprIsRowMajor ? index() : 0; }

  inline Scalar value() const { return m_it.value(); }
  inline Scalar& valueRef() { return m_it.valueRef(); }

  inline OuterVectorInnerIterator& operator++()