rand

rand(3f)                                                                rand(3f)



Name
       rand, drand, irand - generates random numbers

Syntax
       integer irand, i, iflag
       real rand, x
       double precision drand, d
       external rand, drand, irand
       ...
       i = irand ( iflag )
       x = rand ( iflag )
       d = drand ( iflag )

Description
       The rand and drand functions generate pseudo-random numbers distributed
       in [0, 1.0].

       The irand function generates successive pseudo-random integers in the
       range from 0 to RAND_MAX (generally 2**15-1 for integer*4).

       If iflag is '0', the generator returns the next random number in the
       sequence.

       If iflag is '1', the generator is restarted and the first random value is
       returned.

       If iflag is otherwise non-zero, it is used as a new seed for the random
       number generator, and the first new random value is returned.

Files
       libU77.a

See Also
       rand(3), random(3)

Notes
       This impilmentation of rand is compatable with that provided with the
       SunOS and BSD UNIX Fortran 77 compilers. Other compilers do things
       differently, with a seperate call to seed the random number generator (I
       prefer the latter approach, but for no good reason I have gone the BSD
       way).

       Anyone who wants real pseudo-random numbers and real performance will
       want to write their own code. Try reading knuth.



                                                                        rand(3f)