make.link                package:base                R Documentation

_C_r_e_a_t_e _a _L_i_n_k _f_o_r _G_L_M _f_a_m_i_l_i_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     This function is used with the `family' functions in `glm()'.
     Given a link, it returns a link function, an inverse link
     function, the derivative dmu/deta and a function for domain
     checking.

_U_s_a_g_e:

     make.link(link)

_A_r_g_u_m_e_n_t_s:

    link: character or numeric; one of `"logit"', `"probit"',
          `"cloglog"', `"identity"', `"log"',  `"sqrt"',  `"1/mu^2"',
          `"inverse"', or number, say lambda resulting in power link mu
          ^ lambda.

_V_a_l_u_e:

     A list with components 

 linkfun: Link function `function(mu)'

 linkinv: Inverse link function `function(eta)'

  mu.eta: Derivative `function(eta)' dmu/deta

valideta: `function(eta)'{ `TRUE' if all of `eta' is in the domain of
          `linkinv' }.

_S_e_e _A_l_s_o:

     `glm', `family'.

_E_x_a_m_p_l_e_s:

     str(make.link("logit"))

     l2 <- make.link(2)
     l2$linkfun(0:3)# 0 1 4 9
     l2$mu.eta(eta= 1:2)#= 1/(2*sqrt(eta))

