

getInitial {nls}                             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 parame-
     terized data frame or `pframe' object, its `parameters'
     attribute is returned.  Otherwise the object is exam-
     ined 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 for-
          mula 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 `selfS-
     tart' 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', `selfS-
     tart.formula'

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

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

