(PHP 3>= 3.0.6, PHP 4 >= 4.0.0)
mt_rand -- Generate a better random value
Description
int
mt_rand ( [int min, int max])
Many random number generators of older libcs have dubious or
unknown characteristics and are slow. By default, PHP uses the
libc random number generator with the rand()
function. mt_rand() function is a drop-in
replacement for this. It uses a random number generator with
known characteristics, the Mersenne Twister, which will produce
random numbers that should be suitable for seeding some kinds
of cryptography (see the home pages for details) and is four
times faster than what the average libc provides. The Homepage
of the Mersenne Twister can be found at
http://www.math.keio.ac.jp/~matumoto/emt.html, and an
optimized version of the MT source is available from
http://www.scp.syr.edu/~marc/hawk/twister.html
.
If called without the optional min,
max arguments mt_rand()
returns a pseudo-random value between 0 and
RAND_MAX. If you want a random number
between 5 and 15 (inclusive), for example, use mt_rand
(5, 15).
Remember to seed the random number generator before use with
mt_srand().
Note:
In versions before 3.0.7 the meaning of
max was range. To
get the same results in these versions the short example should
be mt_rand (5, 11) to get a random number
between 5 and 15.
See also mt_srand(),
mt_getrandmax(), srand(),
rand() and getrandmax().
