Random number generator (included): Difference between revisions
(Added Java) |
No edit summary |
||
| Line 6: | Line 6: | ||
=={{header|Java}}== |
=={{header|Java}}== |
||
Java's <code>Random</code> class uses a [[wp:Linear congruential generator|Linear congruential formula]], as described in [http://java.sun.com/javase/6/docs/api/java/util/Random.html its documentation]. |
Java's <code>Random</code> class uses a [[wp:Linear congruential generator|Linear congruential formula]], as described in [http://java.sun.com/javase/6/docs/api/java/util/Random.html its documentation]. |
||
=={{header|PHP}}== |
|||
PHP has two random number generators: <code>[http://us3.php.net/manual/en/function.rand.php rand]</code>, which uses the underlying C library's <code>rand</code> function; and <code>[http://us3.php.net/manual/en/function.mt-rand.php mt_rand]</code>, which uses the [[wp:Mersenne twister|Mersenne twister]] algorithm. |
|||
=={{header|Python}}== |
=={{header|Python}}== |
||
Python uses the [[wp:Mersenne twister|Mersenne twister]] algorithm accessed via the built-in [http://docs.python.org/library/random.html random module]. |
Python uses the [[wp:Mersenne twister|Mersenne twister]] algorithm accessed via the built-in [http://docs.python.org/library/random.html random module]. |
||
=={{header|Ruby}}== |
|||
Ruby's <code>rand</code> function currently uses the [[wp:Mersenne twister|Mersenne twister]] algorithm, as described in [http://www.ruby-doc.org/core/classes/Kernel.html#M005974 its documentation]. |
|||
=={{header|Tcl}}== |
=={{header|Tcl}}== |
||
Revision as of 21:45, 23 January 2010
State the type of random number generator algorithm used in a languages built-in random number generator, or omit the language if no random number generator is given as part of the language or its immediate libraries.
If possible, a link to a wider explanation of the algorithm used should be given.
Note: the task is not to create an RNG, but to report on the languages in-built RNG that would be the most likely RNG used.
Java
Java's Random class uses a Linear congruential formula, as described in its documentation.
PHP
PHP has two random number generators: rand, which uses the underlying C library's rand function; and mt_rand, which uses the Mersenne twister algorithm.
Python
Python uses the Mersenne twister algorithm accessed via the built-in random module.
Ruby
Ruby's rand function currently uses the Mersenne twister algorithm, as described in its documentation.
Tcl
Tcl uses a linear congruential generator in it's built-in rand() function. This is seeded by default from the system time, and kept per-interpreter so different security contexts and different threads can't affect each other's generators (avoiding key deployment issues with the rand function from C's math library).
Citations (from Tcl source code):
- S.K. Park & K.W. Miller, “Random number generators: good ones are hard to find,” Comm ACM 31(10):1192-1201, Oct 1988
- W.H. Press & S.A. Teukolsky, “Portable random number generators,” Computers in Physics 6(5):522-524, Sep/Oct 1992.