diff options
Diffstat (limited to 'Doc/lib/librandom.tex')
| -rw-r--r-- | Doc/lib/librandom.tex | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/Doc/lib/librandom.tex b/Doc/lib/librandom.tex index 4e4d615..9d303c2 100644 --- a/Doc/lib/librandom.tex +++ b/Doc/lib/librandom.tex @@ -33,14 +33,15 @@ 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 may be especially useful for multi-threaded programs, although there's -no simple way to seed the distinct generators to ensure that the generated -sequences won't overlap. 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()} -and \method{setstate()} methods. +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. 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()}, +\method{setstate()} and \method{jumpahead()} methods. Bookkeeping functions: @@ -68,6 +69,16 @@ Bookkeeping functions: of the generate to what it was at the time \code{setstate()} was called. \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). + \end{funcdesc} Functions for integers: |