sigmoid                package:e1071                R Documentation

_T_h_e _l_o_g_i_s_t_i_c _f_u_n_c_t_i_o_n _a_n_d _d_e_r_i_v_a_t_i_v_e_s

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

     Sigmoid 1/(1 + exp(-x)), first and second derivative.

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

     sigmoid(x)
     dsigmoid(x)
     d2sigmoid(x)

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

       x: a numeric vector

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

     Friedrich Leisch

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

     plot(sigmoid, -5, 5, ylim = c(-.2, 1))
     plot(dsigmoid, -5, 5, add = TRUE, col = 2)
     plot(d2sigmoid, -5, 5, add = TRUE, col = 3)

