sortedXyData              package:stats              R Documentation

_C_r_e_a_t_e _a _s_o_r_t_e_d_X_y_D_a_t_a _o_b_j_e_c_t

_D_e_s_c_r_i_p_t_i_o_n:

     This is a constructor function for the class of 'sortedXyData'
     objects.  These objects are mostly used in the 'initial' function
     for a self-starting nonlinear regression model, which will be of
     the 'selfStart' class.

_U_s_a_g_e:

     sortedXyData(x, y, data)

_A_r_g_u_m_e_n_t_s:

       x: a numeric vector or an expression that will evaluate in
          'data' to a numeric vector 

       y: a numeric vector or an expression that will evaluate in
          'data' to a numeric vector 

    data: an optional data frame in which to evaluate expressions for
          'x' and 'y', if they are given as expressions 

_V_a_l_u_e:

     A 'sortedXyData' object. This is a data frame with exactly two
     numeric columns, named 'x' and 'y'.  The rows are sorted so the
     'x' column is in increasing order.  Duplicate 'x' values are
     eliminated by averaging the corresponding 'y' values.

_A_u_t_h_o_r(_s):

     Jose Pinheiro and Douglas Bates

_S_e_e _A_l_s_o:

     'selfStart', 'NLSstClosestX', 'NLSstLfAsymptote',
     'NLSstRtAsymptote'

_E_x_a_m_p_l_e_s:

     DNase.2 <- DNase[ DNase$Run == "2", ]
     sortedXyData( expression(log(conc)), expression(density), DNase.2 )