Mercurial > cpython-lru_cache-weakref
diff Lib/random.py @ 38732:bf4e485becf3 legacy-trunk
shuffle() doscstring: Removed warning about sequence length
versus generator period. While this was a real weakness of the
older WH generator for lists with just a few dozen elements,
and so could potentially bite the naive ;-), the Twister should
show excellent behavior up to at least 600 elements.
Module docstring: reflowed some jarringly short lines.
| author | Tim Peters <tim.peters@gmail.com> |
|---|---|
| date | Sat, 10 Jun 2006 22:51:45 +0000 |
| parents | 98251780236d |
| children | 96d533efbe7d |
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--- a/Lib/random.py Sat Jun 10 22:38:13 2006 +0000 +++ b/Lib/random.py Sat Jun 10 22:51:45 2006 +0000 @@ -29,13 +29,12 @@ General notes on the underlying Mersenne Twister core generator: * The period is 2**19937-1. -* It is one of the most extensively tested generators in existence -* Without a direct way to compute N steps forward, the - semantics of jumpahead(n) are weakened to simply jump - to another distant state and rely on the large period - to avoid overlapping sequences. -* The random() method is implemented in C, executes in - a single Python step, and is, therefore, threadsafe. +* It is one of the most extensively tested generators in existence. +* Without a direct way to compute N steps forward, the semantics of + jumpahead(n) are weakened to simply jump to another distant state and rely + on the large period to avoid overlapping sequences. +* The random() method is implemented in C, executes in a single Python step, + and is, therefore, threadsafe. """ @@ -253,11 +252,6 @@ Optional arg random is a 0-argument function returning a random float in [0.0, 1.0); by default, the standard random.random. - - Note that for even rather small len(x), the total number of - permutations of x is larger than the period of most random number - generators; this implies that "most" permutations of a long - sequence can never be generated. """ if random is None: