getInitial               package:stats               R Documentation

_G_e_t _I_n_i_t_i_a_l _P_a_r_a_m_e_t_e_r _E_s_t_i_m_a_t_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     This function evaluates initial parameter estimates for a
     nonlinear regression model.  If 'data' is a parameterized data
     frame or 'pframe' object, its 'parameters' attribute is returned.
     Otherwise the object is examined to see if it contains a call to a
     'selfStart' object whose 'initial' attribute can be evaluated.

_U_s_a_g_e:

     getInitial(object, data, ...)

_A_r_g_u_m_e_n_t_s:

  object: a formula or a 'selfStart' model that defines a nonlinear
          regression model

    data: a data frame in which the expressions in the formula or
          arguments to the 'selfStart' model can be evaluated

     ...: optional additional arguments

_V_a_l_u_e:

     A named numeric vector or list of starting estimates for the
     parameters.  The construction of many 'selfStart' models is such
     that these "starting" estimates are, in fact, the converged
     parameter estimates.

_A_u_t_h_o_r(_s):

     Jose Pinheiro and Douglas Bates

_S_e_e _A_l_s_o:

     'nls',  'selfStart', 'selfStart.default', 'selfStart.formula'

_E_x_a_m_p_l_e_s:

     data(Puromycin)
     PurTrt <- Puromycin[ Puromycin$state == "treated", ]
     getInitial( rate ~ SSmicmen( conc, Vm, K ), PurTrt )

