| (INTRO.DISTR) {distr} | R Documentation |
``distr'' is a package for R from version 1.8.1 onwards that is distributed under GPL license 2.0. Its own current version is 1.6.
The aim of this package is to provide a conceptual treatment of random variables (r.v.'s) by means of S4 classes.
A mother class Distribution is introduced with slots for a parameter and —most important—
for the four constitutive methods r, d, p, and q for simulation respectively for evaluation of
density / c.d.f. and quantile function of the corresponding distribution. All distributions of the base package for which corresponding
r-, d-, p-, and q-functions exist (like normal, Poisson, etc.)
are implemented as subclasses of either AbscontDistribution or DiscreteDistribution,
which themselves are again subclasses of Distribution.
This approach seems very appealing to us from a conceptual viewpoint:
Just pass an object of some derived distribution class to a generic function as argument and let the dispatching mechanism decide what to do on run-time.
As an example, we may automatically generate new objects of these classes with corresponding
r, d, p, and q-slots for the laws of r.v.'s under standard mathematical
univariate transformations and under convolution of independent r.v.'s. For Distribution objects X
and Y expressions like
3*X+sin(exp(-Y/4+3)) have their natural interpretation as corresponding image distributions.
A somewhat longer and more detailed manual can be obtained under
http://www.uni-bayreuth.de/departments/math/org/mathe7/DISTR/
library("distr")