* matrix[0]=m_xx, matrix[1]=m_yy, matrix[2]=m_zz,
* matrix[3]=m_xy, matrix[4]=m_yz, matrix[5]=m_xz
* This method returns the eigenvector of the corresponding eigenvalue in 'eigenVal'. The returned eigenValue is normalized.
* matrix[0]=m_xx, matrix[1]=m_yy, matrix[2]=m_zz,
* matrix[3]=m_xy, matrix[4]=m_yz, matrix[5]=m_xz
* This method returns the eigenvector of the corresponding eigenvalue in 'eigenVal'. The returned eigenValue is normalized.