With a positive integer as an argument, randomize(n) will use the given value to initialize the state in the default random number generator. With no arguments, randomize() will use a number based on the system clock to initialize the state of the random number generator.

The return value will be the seed used to initialize the state of the random number generator.  If n is specified the return value is n.

randomize calls RandomTools[MersenneTwister][SetState].  It is more efficient to make this call directly than to call randomize.

By passing the value returned by randomize into a subsequent call to randomize the same sequence of numbers will be generated.

Since the no argument form of randomize() depends on the system clock, the same seed can be obtained if not enough time elapses between two consecutive calls to randomize().

$\mathrm{Seed}≔\mathrm{randomize}\left(\right)$

$\mathrm{Seed}≔26879001555$

$\mathrm{rand}\left(\right)$

$636553379956$

$\mathrm{rand}\left(\right)$

$369926448872$

$\mathrm{randomize}\left(\mathrm{Seed}\right)$

$26879001555$

$\mathrm{rand}\left(\right)$

$636553379956$