LU-class               package:Matrix               R Documentation

_L_U _M_a_t_r_i_x _D_e_c_o_m_p_o_s_i_t_i_o_n_s

_D_e_s_c_r_i_p_t_i_o_n:

     The '"LU"' class is the class of LU decompositions of real
     matrices.

_O_b_j_e_c_t_s _f_r_o_m _t_h_e _C_l_a_s_s:

     Objects can be created by calls of the form 'new("LU", ...)'. More
     commonly the objects are created explicitly from calls of the form
     'lu(mm)' where 'mm' is an object that inherits from the
     '"dgeMatrix"' class or as a side-effect of other functions applied
     to '"dgeMatrix"' objects.

_S_l_o_t_s:

     '_x': object of class '"numeric"'.  The '"L"' (unit lower
          triangular) and '"U"' (upper triangular) factors of the
          original matrix.  These are stored in a packed format
          described in the Lapack manual.

     '_D_i_m': Object of class '"integer"' - the dimensions of the
          original matrix - must be an integer vector with exactly two
          non-negative values.

     '_p_i_v_o_t': Object of class '"integer"' - a vector of length
          'min(Dim)' that describes the permutation applied to the rows
          of the original matrix.  The contents of this vector are
          described in the Lapack manual.

_M_e_t_h_o_d_s:

     _e_x_p_a_n_d 'signature(x = "LU")': Produce the '"L"' and '"U"' factors
          as a named list of matrices.

_S_e_e _A_l_s_o:

     'dgeMatrix-class', 'lu', 'expand'

_E_x_a_m_p_l_e_s:

     mm <- Matrix(round(rnorm(9),2), nrow = 3, ncol = 3)
     mm
     str(lum <- lu(mm))
     elu <- expand(lum)
     elu
     elu$L %*% elu$U

