From 435cb0f23304d57b0cafb2a4449a41150f7fffa9 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Mon, 6 Sep 2010 23:36:31 +0000 Subject: [PATCH] Document which part of the random module module are guaranteed. --- Doc/library/random.rst | 16 ++++++++++++++++ Misc/NEWS | 5 +++++ 2 files changed, 21 insertions(+) diff --git a/Doc/library/random.rst b/Doc/library/random.rst index bf89ade3d3..6ef5d209fc 100644 --- a/Doc/library/random.rst +++ b/Doc/library/random.rst @@ -270,3 +270,19 @@ Examples of basic usage:: `_ for a compatible alternative random number generator with a long period and comparatively simple update operations. + +Notes on Reproducibility +======================== + +Sometimes it is useful to be able to reproduce the sequences given by a pseudo +random number generator. By re-using a seed value, the same sequence should be +reproducible from run to run as long as multiple threads are not running. + +Most of the random module's algorithms and seeding functions are subject to +change across Python versions, but two aspects are guaranteed not to change: + +* If a new seeding method is added, then a backward compatible seeder will be + offered. + +* The generator's :meth:`random` method will continue to produce the same + sequence when the compatible seeder is given the same seed. diff --git a/Misc/NEWS b/Misc/NEWS index 262983b313..014164ea7d 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -13,6 +13,11 @@ Core and Builtins Library ------- +- Updates to the random module: + + * Document which parts of the module are guaranteed to stay the same + across versions and which parts are subject to change. + - collections.OrderedDict now supports a new method for repositioning keys to either end. -- 2.49.0