acompmargin           package:compositions           R Documentation

_M_a_r_g_i_n_a_l _c_o_m_p_o_s_i_t_i_o_n_s _i_n _A_i_t_c_h_i_s_o_n _C_o_m_p_o_s_i_t_i_o_n_s

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

     Compute marginal compositions of selected parts, by computing the
     rest as the geometric mean of the non-selected parts.

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

               acompmargin(X,d=c(1,2),name="*",pos=length(d)+1)
               

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

       X: composition or dataset of compositions

       d: vector containing the indices xor names of the columns
          selected

    name: The new name of the amalgamation column

     pos: The position where the new amalgamation column should be
          stored. This defaults to the last column.

_D_e_t_a_i_l_s:

     The amalgamation column is simply computed by taking the geometric
     mean of the non-selected components. This is consistent with the
     'acomp' approach and gives clear ternary diagrams. However, this
     geometric mean is difficult to interpret.

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

     A closed compositions with class '"acomp"' containing the
     variables given by 'd' and the the amalgamation column.

_R_e_f_e_r_e_n_c_e_s:

     Vera Pawlowsky-Glahn (2003) personal communication. Seminaris 
     d'Estadstica, Departament d'Informtica i Matemtica Aplicada,
     Universitat de Girona.

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

     'rcompmargin', 'acomp'

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

     data(SimulatedAmounts)
     plot.acomp(sa.lognormals5,margin="acomp")
     plot.acomp(acompmargin(sa.lognormals5,c("Pb","Zn")))
     plot.acomp(acompmargin(sa.lognormals5,c(1,2)))

