pdMatrix.reStruct            package:nlme            R Documentation

_E_x_t_r_a_c_t _M_a_t_r_i_x _o_r _S_q_u_a_r_e-_R_o_o_t _F_a_c_t_o_r _f_r_o_m _C_o_m_p_o_n_e_n_t_s _o_f _a_n
_r_e_S_t_r_u_c_t _O_b_j_e_c_t

_D_e_s_c_r_i_p_t_i_o_n:

     This method function extracts the positive-definite  matrices
     corresponding to the 'pdMat' elements of 'object', or square-root
     factors of the positive-definite matrices.

_U_s_a_g_e:

     ## S3 method for class 'reStruct':
     pdMatrix(object, factor)

_A_r_g_u_m_e_n_t_s:

  object: an object inheriting from class 'reStruct', representing a
          random effects structure and consisting of a list of 'pdMat'
          objects.

  factor: an optional logical value. If 'TRUE', square-root factors of
          the positive-definite matrices represented by the elements of
          'object' are returned; else, if 'FALSE', the
          positive-definite matrices are returned. Defaults to 'FALSE'.

_V_a_l_u_e:

     a list with components given by the positive-definite matrices
     corresponding to the elements of 'object', or square-root factors
     of the positive-definite matrices.

_A_u_t_h_o_r(_s):

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

_R_e_f_e_r_e_n_c_e_s:

     Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S
     and S-PLUS", Springer, esp. p. 162.

_S_e_e _A_l_s_o:

     'as.matrix.reStruct', 'reStruct', 'pdMat',  'pdMatrix', 
     'pdMatrix.pdMat'

_E_x_a_m_p_l_e_s:

     rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont))
     pdMatrix(rs1)