traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Minor markup adjustments.

This commit is contained in:
Fred Drake 2001-02-02 02:42:31 +00:00
parent 68b6417c5a
commit 844bd5b4a9
1 changed files with 26 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
Doc/lib/librandom.tex
View File

@ -34,15 +34,17 @@ Else, because no critical sections are implemented internally, calls
from different threads may see the same return values.
The functions supplied by this module are actually bound methods of a
hidden instance of the \var{random.Random} class. You can instantiate your
own instances of \var{Random} to get generators that don't share state.
This is especially useful for multi-threaded programs, creating a different
instance of \var{Random} for each thread, and using the \method{jumpahead()}
method to ensure that the generated sequences seen by each thread don't
overlap (see example below).
Class \var{Random} can also be subclassed if you want to use a different
basic generator of your own devising: in that case, override the
\method{random()}, \method{seed()}, \method{getstate()},
hidden instance of the \class{random.Random} class. You can
instantiate your own instances of \class{Random} to get generators
that don't share state. This is especially useful for multi-threaded
programs, creating a different instance of \class{Random} for each
thread, and using the \method{jumpahead()} method to ensure that the
generated sequences seen by each thread don't overlap (see example
below).
Class \class{Random} can also be subclassed if you want to use a
different basic generator of your own devising: in that case, override
the \method{random()}, \method{seed()}, \method{getstate()},
\method{setstate()} and \method{jumpahead()} methods.
Here's one way to create threadsafe distinct and non-overlapping generators:
@ -117,27 +119,29 @@ Bookkeeping functions:
\end{funcdesc}
\begin{funcdesc}{getstate}{}
Return an object capturing the current internal state of the generator.
This object can be passed to \code{setstate()} to restore the state.
Return an object capturing the current internal state of the
generator. This object can be passed to \function{setstate()} to
restore the state.
\versionadded{2.1}
\end{funcdesc}
\begin{funcdesc}{setstate}{state}
\var{state} should have been obtained from a previous call to
\code{getstate()}, and \code{setstate()} restores the internal state
of the generator to what it was at the time \code{setstate()} was called.
\function{getstate()}, and \function{setstate()} restores the
internal state of the generator to what it was at the time
\function{setstate()} was called.
\versionadded{2.1}
\end{funcdesc}
\end{funcdesc}
\begin{funcdesc}{jumpahead}{n}
Change the internal state to what it would be if \code{random()} were
called n times, but do so quickly. \var{n} is a non-negative integer.
This is most useful in multi-threaded programs, in conjuction with
multiple instances of the \var{Random} class: \method{setstate()} or
\method{seed()} can be used to force all instances into the same
internal state, and then \method{jumpahead()} can be used to force the
instances' states as far apart as you like (up to the period of the
generator).
Change the internal state to what it would be if \function{random()}
were called \var{n} times, but do so quickly. \var{n} is a
non-negative integer. This is most useful in multi-threaded
programs, in conjuction with multiple instances of the \var{Random}
class: \method{setstate()} or \method{seed()} can be used to force
all instances into the same internal state, and then
\method{jumpahead()} can be used to force the instances' states as
far apart as you like (up to the period of the generator).
\versionadded{2.1}
\end{funcdesc}