


      RRRRAAAANNNNDDDDOOOOMMMM((((3333CCCC))))                  ((((bbbbssssdddd 4444....2222))))                  RRRRAAAANNNNDDDDOOOOMMMM((((3333CCCC))))



      NNNNAAAAMMMMEEEE
           random, srandom, initstate, setstate - better random number
           generator; routines for changing generators

      SSSSYYYYNNNNTTTTAAAAXXXX
           lllloooonnnngggg rrrraaaannnnddddoooommmm(((())))

           ssssrrrraaaannnnddddoooommmm((((sssseeeeeeeedddd))))
           iiiinnnntttt sssseeeeeeeedddd;;;;

           cccchhhhaaaarrrr ****iiiinnnniiiittttssssttttaaaatttteeee((((sssseeeeeeeedddd,,,, ssssttttaaaatttteeee,,,, nnnn))))
           uuuunnnnssssiiiiggggnnnneeeedddd sssseeeeeeeedddd;;;;
           cccchhhhaaaarrrr ****ssssttttaaaatttteeee;;;;
           iiiinnnntttt nnnn;;;;

           cccchhhhaaaarrrr ****sssseeeettttssssttttaaaatttteeee((((ssssttttaaaatttteeee))))
           cccchhhhaaaarrrr ****ssssttttaaaatttteeee;;;;

      DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
           _R_a_n_d_o_m uses a non-linear additive feedback random number
           generator employing a default table of size 31 long integers
           to return successive pseudo-random numbers in the range from
           0 to 28319-1.  The period of this random number generator is
           very large, approximately 16*(28319-1).

           _R_a_n_d_o_m/_s_r_a_n_d_o_m have (almost) the same calling sequence and
           initialization properties as _r_a_n_d/_s_r_a_n_d. The difference is
           that _r_a_n_d(3) produces a much less random sequence -- in
           fact, the low dozen bits generated by rand go through a
           cyclic pattern.  All the bits generated by _r_a_n_d_o_m are
           usable.  For example, random()&01 will produce a random
           binary value.

           Unlike _s_r_a_n_d, _s_r_a_n_d_o_m does not return the old seed; the
           reason for this is that the amount of state information used
           is much more than a single word.  (Two other routines are
           provided to deal with restarting/changing random number
           generators.)
             Like _r_a_n_d(3), however, _r_a_n_d_o_m will by default produce a
           sequence of numbers that can be duplicated by calling
           _s_r_a_n_d_o_m with _1 as the seed.

           The _i_n_i_t_s_t_a_t_e routine allows a state array, passed in as an
           argument, to be initialized for future use.  The size of the
           state array (in bytes) is used by _i_n_i_t_s_t_a_t_e to decide how
           sophisticated a random number generator it should use -- the
           more state, the better the random numbers will be.  (Current
           "optimal" values for the amount of state information are 8,
           32, 64, 128, and 256 bytes; other amounts will be rounded
           down to the nearest known amount.  Using less than 8 bytes
           will cause an error.) The seed for the initialization (which
           specifies a starting point for the random number sequence,



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      RRRRAAAANNNNDDDDOOOOMMMM((((3333CCCC))))                  ((((bbbbssssdddd 4444....2222))))                  RRRRAAAANNNNDDDDOOOOMMMM((((3333CCCC))))



           and provides for restarting at the same point) is also an
           argument.  _I_n_i_t_s_t_a_t_e returns a pointer to the previous state
           information array.

           Once a state has been initialized, the _s_e_t_s_t_a_t_e routine
           provides for rapid switching between states.  _S_e_t_s_t_a_t_e
           returns a pointer to the previous state array; its argument
           state array is used for further random number generation
           until the next call to _i_n_i_t_s_t_a_t_e or _s_e_t_s_t_a_t_e.

           Once a state array has been initialized, it may be restarted
           at a different point either by calling _i_n_i_t_s_t_a_t_e (with the
           desired seed, the state array, and its size) or by calling
           both _s_e_t_s_t_a_t_e (with the state array) and _s_r_a_n_d_o_m (with the
           desired seed).  The advantage of calling both _s_e_t_s_t_a_t_e and
           _s_r_a_n_d_o_m is that the size of the state array does not have to
           be remembered after it is initialized.

           With 256 bytes of state information, the period of the
           random number generator is greater than 28699, which should be
           sufficient for most purposes.

      AAAAUUUUTTTTHHHHOOOORRRR
           University of California, Berkeley

      DDDDIIIIAAAAGGGGNNNNOOOOSSSSTTTTIIIICCCCSSSS
           If _i_n_i_t_s_t_a_t_e is called with less than 8 bytes of state
           information, or if _s_e_t_s_t_a_t_e detects that the state
           information has been garbled, error messages are printed on
           the standard error output.

      SSSSEEEEEEEE AAAALLLLSSSSOOOO
           rand(3)

      BBBBUUUUGGGGSSSS
           About 2/3 the speed of _r_a_n_d(3C).



















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