Method setZero

deps/Eigen/src/SparseCore/SparseMatrix.h:303–309

Removes all non zeros but keep allocated memory * * This function does not free the currently allocated memory. To release as much as memory as possible, * call \code mat.data().squeeze(); \endcode after resizing it. * * \sa resize(Index,Index), data() */

   * \sa resize(Index,Index), data()
   */
  inline void setZero() {
    m_data.clear();
    std::fill_n(m_outerIndex, m_outerSize + 1, StorageIndex(0));
    if (m_innerNonZeros) {
      std::fill_n(m_innerNonZeros, m_outerSize, StorageIndex(0));
    }
  }

  /** Preallocates \a reserveSize non zeros.
   *