qerror                  package:som                  R Documentation

_q_u_a_n_t_i_z_a_t_i_o_n _a_c_c_u_r_a_c_y

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

     get the average distortion measure

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

     qerror(obj, err.radius=1)

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

     obj: a `som' object 

err.radius: radius used calculating qerror 

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

     An average of the following quantity (weighted distance measure)
     over all x in the sample,

                         sum |x - m_i| h_{ci}

     where h_{ci} is the neighbourhood kernel for the ith code.

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

     Jun Yan <jyan@stat.uiowa.edu>

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

     foo <- som(matrix(rnorm(1000), 100), 2, 4)
     qerror(foo, 3)

