pqR - a "pretty quick" implementation of the R programming language

This directory contains the source code (plus documentation) for an
implementation of the R programming language, including some R
packages.  This implementation is a modification of R-2.15.0,
distributed by the R Core Team, and found at www.r-project.org.  
Some modules are taken from R-2.15.1 and later R Core Team releases.

The modifications in pqR substantially improve the speed of R.  Some
extensions to R are also implemented.  These modifications were
written by Radford M. Neal, radfordneal@gmail.com.

For information on pqR, see project web page at pqR-project.org, and
the git repository for the source code at github.com/radfordneal/pqR,
which includes modification history.

This implementation of R is distributed under the GNU General Public
Licence, version 2 or version 3.  See the file COPYING for a copy of
version 2 of the GNU General Public Licence, and the files in
share/licenses for copies of other licenses.  See doc/COPYRIGHTS for
futher details on copyright of this software.

See the files INSTALL, NEWS, and MODS (or the directory "mods-dir" if
you are looking at a development version) for more information.  The
"doc" directory contains much additional documentation.

-----------------------------------------------------------------------------

                     THE BASIC R README

           (from R-2.15.0, distributed 2012-03-30)


	   (See "doc/FAQ" and "doc/RESOURCES" for more detailed information
				      - these files are only in the tarballs)
	   (See "INSTALL"             for help on installation)

1. INTRODUCTION

This directory contains the source code tree for R, which is a
language which is not entirely unlike (versions 3 and 4 of) the S
language developed at AT&T Bell Laboratories by Rick Becker, John
Chambers and Allan Wilks.

R is free software distributed under a GNU-style copyleft.

The core of R is an interpreted computer language with a syntax
superficially similar to C, but which is actually a "functional
programming language" with capabilities similar to Scheme.  The
language allows branching and looping as well as modular programming
using functions.  Most of the user-visible functions in R are written
in R, calling upon a smaller set of internal primitives.  It is
possible for the user to interface to procedures written in C or
Fortran languages for efficiency, and also to write additional
primitives.

The R distribution contains functionality for a large number of
statistical procedures.  Among these are: linear and generalized
linear models, nonlinear regression models, time series analysis,
classical parametric and nonparametric tests, clustering and
smoothing.  There is also a large set of functions which provide a
flexible graphical environment for creating various kinds of data
presentations.

A package specification allows the production of loadable modules for
specific purposes, and several hundred contributed packages are made
available through the CRAN sites (see
http://CRAN.R-project.org/mirrors.html for the current members).


2. HISTORY

R was initially written by Robert Gentleman and Ross Ihaka of the
Statistics Department of the University of Auckland.  In addition, a
large group of individuals has contributed to R by sending code and bug
reports.

Since mid-1997 there has been a core group who can modify the R source
code archive, listed in file doc/AUTHORS.

R 1.0.0 was released on 29 February 2000 and 2.0.0 on 4 October 2004.


3. PRESENT STATUS

The present version implements most of the functionality in the 1988
book "The New S Language" (the "Blue Book") and many of the
applications.  In addition, we have implemented a large part of the
functionality from the 1992 book "Statistical Models in S" (the "White
Book") and the 1998 book "Programming with Data" (the "Green Book").

All the R functions have been documented in the form of help pages in
an "output independent" form which can be used to create versions for
HTML, LaTeX, text etc.  A 1800+ page Reference Index (a collection of
all the help pages) can be obtained in a variety of formats.  The
manual `An Introduction to R' provides a more user-friendly starting
point, and there is an `R Language Definition' manual and more
specialized manuals on data import/export and extending R.  See INSTALL
for instructions on how to generate these documents.


4. GOALS

Our aim at the start of this project was to demonstrate that it was
possible to produce an S-like environment which did not suffer from
the memory-demands and performance problems which S has.  Somewhat
later, we started to turn R into a "real" system, but unfortunately we
lost a large part of the efficiency advantage in the process, so have
revised the memory management mechanism and implemented delayed
loading of R objects.  A lot of performance tuning has been done,
including the ability to use tuned linear-algebra libraries.

Longer-term goals include to explore new ideas: e.g. virtual objects
and component-based programming, and expanding the scope of existing
ones like formula-based interfaces.  Further, we wish to get a handle
on a general approach to graphical user interfaces (preferably with
cross-platform portability), and to develop better 3-D and dynamic
graphics.


Sincerely,
The R Core Team.