

reStruct(nlme)                               R Documentation

_R_a_n_d_o_m _E_f_f_e_c_t_s _S_t_r_u_c_t_u_r_e

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

     This function is a constructor for the `reStruct'
     class, representing a random effects structure and con-
     sisting of a list of `pdMat' objects, plus a `settings'
     attribute containing information for the optimization
     algorithm used to fit the associated mixed-effects
     model.

_U_s_a_g_e_:

     reStruct(object, pdClass, RML, data)

_A_r_g_u_m_e_n_t_s_:

  object: any of the following: (i) a one-sided formula of
          the form `~x1+...+xn | g1/.../gm', with
          `x1+...+xn' specifying the model for the random
          effects and `g1/.../gm' the grouping structure
          (`m' may be equal to 1, in which case no `/' is
          required). The random effects formula will be
          repeated for all levels of grouping, in the case
          of multiple levels of grouping; (ii) a list of
          one-sided formulas of the form `~x1+...+xn | g',
          with possibly different random effects models for
          each grouping level. The order of nesting will be
          assumed the same as the order of the elements in
          the list; (iii) a one-sided formula of the form
          `~x1+...+xn', or a `pdMat' object with a formula
          (i.e. a non-`NULL' value for `formula(object)'),
          or a list of such formulas or `pdMat' objects. In
          this case, the grouping structure formula will be
          derived from the data used to to fit the mixed-
          effects model, which should inherit from class
          `groupedData'; (iv) a named list of formulas or
          `pdMat' objects as in (iii), with the grouping
          factors as names. The order of nesting will be
          assumed the same as the order of the order of the
          elements in the list; (v) an `reStruct' object.

 pdClass: an optional character string with the name of the
          `pdMat' class to be used for the formulas in
          `object'. Defaults to `"pdSymm"' which corresponds
          to a general positive-definite matrix.

     RML: an optional logical value. If `TRUE', the associ-
          ated mixed-effects model will be fitted using
          restricted maximum likelihood; else, if `FALSE',
          maximum likelihood will be used. Defaults to
          `FALSE'.

    data: an optional data frame in which to evaluate the
          variables used in the random effects formulas in
          `object'. It is used to obtain the levels for
          `factors', which affect the dimensions and the
          row/column names of the underlying `pdMat'
          objects. If `NULL', no attempt is made to obtain
          information on `factors' appearing in the formu-
          las. Defaults to the parent frame from which the
          function was called.

_V_a_l_u_e_:

     an object inheriting from class `reStruct', represent-
     ing a random effects structure.

_A_u_t_h_o_r_(_s_)_:

     Jose Pinheiro and Douglas Bates

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

     `pdMat', `lme', `groupedData'

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

     library(nlme)
     data(Pixel)
     rs1 <- reStruct(list(Dog = ~day, Side = ~1), data = Pixel)
     rs1

