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Merged changes from the 1.5.2p2 release.

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Fred Drake 2000-04-03 20:13:55 +00:00
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68
Doc/lib/librandom.tex
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@ -12,22 +12,25 @@ or Gaussian, lognormal, negative exponential, gamma, and beta
distributions. For generating distribution of angles, the circular
uniform and von Mises distributions are available.
The module exports the following functions, which are exactly
equivalent to those in the \refmodule{whrandom} module:
\function{choice()}, \function{randint()}, \function{random()} and
\function{uniform()}. See the documentation for the
\refmodule{whrandom} module for these functions.
The following functions specific to the \module{random} module are also
defined, and all return real values. Function parameters are named
after the corresponding variables in the distribution's equation, as
used in common mathematical practice; most of these equations can be
found in any statistics text.
The \module{random} module supports the \emph{Random Number
Generator} interface, described in section \ref{rng-objects}. This
interface of the module, as well as the distribution-specific
functions described below, all use the pseudo-random generator
provided by the \refmodule{whrandom} module.
The following functions are defined to support specific distributions,
and all return real values. Function parameters are named after the
corresponding variables in the distribution's equation, as used in
common mathematical practice; most of these equations can be found in
any statistics text. These are expected to become part of the Random
Number Generator interface in a future release.
\begin{funcdesc}{betavariate}{alpha, beta}
Beta distribution. Conditions on the parameters are
\code{\var{alpha} >- 1} and \code{\var{beta} > -1}.
Returned values will range between 0 and 1.
\code{\var{alpha} > -1} and \code{\var{beta} > -1}.
Returned values range between 0 and 1.
\end{funcdesc}
\begin{funcdesc}{cunifvariate}{mean, arc}
@ -59,8 +62,8 @@ standard deviation. This is slightly faster than the
\begin{funcdesc}{lognormvariate}{mu, sigma}
Log normal distribution. If you take the natural logarithm of this
distribution, you'll get a normal distribution with mean \var{mu} and
standard deviation \var{sigma}. \var{mu} can have any value, and \var{sigma}
must be greater than zero.
standard deviation \var{sigma}. \var{mu} can have any value, and
\var{sigma} must be greater than zero.
\end{funcdesc}
\begin{funcdesc}{normalvariate}{mu, sigma}
@ -86,5 +89,40 @@ Weibull distribution. \var{alpha} is the scale parameter and
\end{funcdesc}
\begin{seealso}
\seemodule{whrandom}{the standard Python random number generator}
\seemodule{whrandom}{The standard Python random number generator.}
\end{seealso}
\subsection{The Random Number Generator Interface
\label{rng-objects}}
% XXX This *must* be updated before a future release!
The \dfn{Random Number Generator} interface describes the methods
which are available for all random number generators. This will be
enhanced in future releases of Python.
In this release of Python, the modules \refmodule{random},
\refmodule{whrandom}, and instances of the
\class{whrandom.whrandom} class all conform to this interface.
\begin{funcdesc}{choice}{seq}
Chooses a random element from the non-empty sequence \var{seq} and
returns it.
\end{funcdesc}
\begin{funcdesc}{randint}{a, b}
Returns a random integer \var{N} such that
\code{\var{a} <= \var{N} <= \var{b}}.
\end{funcdesc}
\begin{funcdesc}{random}{}
Returns the next random floating point number in the range [0.0
... 1.0).
\end{funcdesc}
\begin{funcdesc}{uniform}{a, b}
Returns a random real number \var{N} such that
\code{\var{a} <= \var{N} < \var{b}}.
\end{funcdesc}