

randu {base}                                 R Documentation

_R_a_n_d_o_m _N_u_m_b_e_r_s _f_r_o_m _C_o_n_g_r_u_e_n_t_i_a_l _G_e_n_e_r_a_t_o_r

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

     400 triples of successive random numbers were taken
     from the VAX FORTRAN function RANDU running under VMS
     1.5.

_U_s_a_g_e_:

     data(randu)

_F_o_r_m_a_t_:

     A data frame with 400 observations on 3 variables named
     `x', `y' and `z' which give the first, second and third
     random number in the triple.

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

     In three dimensional displays it is evident that the
     triples fall on 15 parallel planes in 3-space. This can
     be shown theoretically to be true for all triples from
     the RANDU generator.

     These particular 400 triples start 5 apart in the
     sequence, that is they are ((U[5i+1], U[5i+2],
     U[5i+3]), i= 0, ..., 399), and they are rounded to 6
     decimal places.

     Under VMS versions 2.0 and higher, this problem has
     been fixed.

_S_o_u_r_c_e_:

     David Donoho

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

     ## We could re-generate the dataset by the following R code
     seed <- as.double(1)
     RANDU <- function() {
         seed <<- ((2^16 + 3) * seed)
         seed/(2^31)
     }
     for(i in 1:400) {
         U <- c(RANDU(), RANDU(), RANDU(), RANDU(), RANDU())
         print(round(U[1:3], 6))
     }

