hlog                  package:affy                  R Documentation

_H_y_b_r_i_d _L_o_g

_D_e_s_c_r_i_p_t_i_o_n:

     Given a constant 'c' this function returns 'x' if 'x' is less than
     'c' and 'sign(x)*(c*log(abs(x)/c) + c)' if its not. Notice this is
     a continuos odd ( f(-x)=-f(x) ) function with continous first
     derivative. The main purpose is to perform log transformation when
      one has negative numbers, for example for PM-MM.

_U_s_a_g_e:

     hlog(x, constant=1)

_A_r_g_u_m_e_n_t_s:

       x: a number.

constant: the constant c (see description).

_D_e_t_a_i_l_s:

     If 'constant' is less than or equal to 0 'log(x)' is returned for
     all 'x'. If 'constant' is infinity 'x' is returned for all 'x'.

_A_u_t_h_o_r(_s):

     Rafael A. Irizarry