Commit b21dac1e authored by Raymond Hettinger's avatar Raymond Hettinger

Remove outdated reference to Wichmann-Hill algorithm.

parent 05156613
...@@ -8,9 +8,10 @@ ...@@ -8,9 +8,10 @@
This module implements pseudo-random number generators for various This module implements pseudo-random number generators for various
distributions. distributions.
For integers, uniform selection from a range. For sequences, uniform selection For integers, there is uniform selection from a range. For sequences, there is
of a random element, a function to generate a random permutation of a list uniform selection of a random element, a function to generate a random
in-place, and a function for random sampling without replacement. permutation of a list in-place, and a function for random sampling without
replacement.
On the real line, there are functions to compute uniform, normal (Gaussian), On the real line, there are functions to compute uniform, normal (Gaussian),
lognormal, negative exponential, gamma, and beta distributions. For generating lognormal, negative exponential, gamma, and beta distributions. For generating
...@@ -35,15 +36,6 @@ basic generator of your own devising: in that case, override the :meth:`random`, ...@@ -35,15 +36,6 @@ basic generator of your own devising: in that case, override the :meth:`random`,
Optionally, a new generator can supply a :meth:`getrandbits` method --- this Optionally, a new generator can supply a :meth:`getrandbits` method --- this
allows :meth:`randrange` to produce selections over an arbitrarily large range. allows :meth:`randrange` to produce selections over an arbitrarily large range.
As an example of subclassing, the :mod:`random` module provides the
:class:`WichmannHill` class that implements an alternative generator in pure
Python. The class provides a backward compatible way to reproduce results from
earlier versions of Python, which used the Wichmann-Hill algorithm as the core
generator. Note that this Wichmann-Hill generator can no longer be recommended:
its period is too short by contemporary standards, and the sequence generated is
known to fail some stringent randomness tests. See the references below for a
recent variant that repairs these flaws.
The :mod:`random` module also provides the :class:`SystemRandom` class which The :mod:`random` module also provides the :class:`SystemRandom` class which
uses the system function :func:`os.urandom` to generate random numbers uses the system function :func:`os.urandom` to generate random numbers
from sources provided by the operating system. from sources provided by the operating system.
......
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