update.varFunc             package:nlme             R Documentation

_U_p_d_a_t_e _v_a_r_F_u_n_c _O_b_j_e_c_t

_D_e_s_c_r_i_p_t_i_o_n:

     If the 'formula(object)' includes a '"."' term, representing a
     fitted object, the variance covariate needs to be updated upon
     completion of an optimization cycle (in which the variance
     function weights are kept fixed). This method function allows a
     reevaluation of the variance covariate using the current fitted
     object and, optionally, other variables in the original data.

_U_s_a_g_e:

     ## S3 method for class 'varFunc':
     update(object, data, ...)

_A_r_g_u_m_e_n_t_s:

  object: an object inheriting from class 'varFunc', representing a
          variance function structure.

    data: a list with a component named '"."' with the current version
          of the fitted object (from which fitted values, coefficients,
          and residuals can be extracted) and, if necessary, other
          variables used to evaluate the variance covariate(s).

     ...: some methods for this generic require additional arguments. 
          None are used in this method.

_V_a_l_u_e:

     if 'formula(object)' includes a '"."' term, an 'varFunc' object
     similar to 'object', but with the  variance covariate reevaluated
     at the current fitted object value; else 'object' is returned
     unchanged.

_A_u_t_h_o_r(_s):

     Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates
     bates@stat.wisc.edu

_S_e_e _A_l_s_o:

     'needUpdate', 'covariate<-.varFunc'

