Symm                   package:gnm                   R Documentation

_S_y_m_m_e_t_r_i_c _I_n_t_e_r_a_c_t_i_o_n _o_f _F_a_c_t_o_r_s

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

     'Symm' codes the symmetric interaction of factors having the same
     set of levels, for use in regression models of symmetry or 
     quasi-symmetry.

_U_s_a_g_e:

     Symm(...)

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

     ...: one or more factors. 

_V_a_l_u_e:

     A factor whose levels index the symmetric interaction of all
     factors  supplied as input.

_N_o_t_e:

     'Symm' relies on the gtools package from CRAN

_A_u_t_h_o_r(_s):

     David Firth

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

     'Diag'

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

     if (require(gtools)) {
         row <- gl(4, 4, 16)
         col <- gl(4, 1, 16)
         symm4by4 <- Symm(row, col)
         matrix(symm4by4, 4, 4)
     } else cat("Symm requires the gtools package to be installed\n")

