|G. P. Nason, School of Mathematical Sciences, University of Bath
|Posted: Fri Nov 29, 2002 3:32 pm
Subject: Wavelet software in S: version 2.2
|Wavelet transforms and thresholding in 1 and 2 dimensions for s
WHAT: S software to compute the 1- and 2-dimensional wavelet transform
using Mallat's pyramidal algorithm with Daubechies compactly supported
orthonormal wavelets and incorporating an implementation of the
thresholding ideas of Donoho and Johnstone.
Package consists of:
* S functions that compute the 1- and 2-dimensional
discrete wavelet transform, and inverse. (Uses
dynamically loaded C code)
* S functions to perform thresholding
* S functions to plot and interpret sets of wavelet coefficients
* Full on-line S help
NEW IN RELEASE 2.2
* extra method of boundary handling, periodic functions
* new family of wavelets added, Daubechies' least-asymmetric
* new function "draw" that produces nice pictures of
one- and two dimensional wavelets
* new class iwmdc added and facilities to automatically
compress thresholded image wavelet decomp. objects
* improvements to Makefile and automatic dynamic loading.
(Thanks to Peter Clifford, Howard Grubb, and Martin Maechler for
providing suggestions and improvements for wavethresh 2.2)
WHERE: Obtain via anonymous FTP from gdr.bath.ac.uk
Userid "anonymous" and your email address as the password.
Software is in directory /pub/masgpn as the file "wavethresh2.2.Z"
The transfer should be done using the BINARY transfer mode of ftp
and then the files should be uncompressed using the UNIX command
"uncompress". The software can then be unpacked by typing
(on a UNIX machine)
% sh wavethresh2.2
Extra draft documentation is in "dws.ps.Z" - a compressed PostScript
file (for Release 2.1).
***> FOR RELEASE 2.2 documentation contact Guy Nason directly at the
ALSO available from the statlib archive (ftp: lib.stat.cmu.edu)
userid "statlib", your email address as password. The software
is in the "S" directory as "wavethresh".
CONTACT: firstname.lastname@example.org for further information
After Release 2.1 I received many questions along the lines of "what is S?".
The following information is culled from the S frequently asked questions
list and from the s-news digest.
WHAT ARE S & SPlus?
From the Frequently asked questions (FAQ) list:
4) What is S? What can S be used for?
S is a very high level language and an environment for data
analysis and graphics. S was written by Richard A. Becker,
John M. Chambers, and Allan R. Wilks of AT&T Bell Laboratories
Statistics Research Department. More recently, other Bell Labs
researchers have made major contributions to a new modeling
capability in S.
The S language is the form in which S users express their
computations. The environment provides facilities for data
management, support for many graphics devices, etc.
S is useful for computation in a wide range of applications.
It's a very general tool, so that applications are not res-
tricted to any particular subject area. One way to think of it
is to imagine the wide range of applications that can be han-
dled by a spreadsheet program - but think of an even broader
range of applications because S is much more flexible for com-
plex computations. As examples, S has been used for computing
in business, finance, experimental science, etc.
The authors of S prefer that you not call S a statistics package.
Most of the people who use S have no attachment to statistics,
and most of the S applications involve basic quantitative
computations and graphics. ``Package'' really doesn't apply well
to S, either. The word ``package'' often connotes a collection
of unrelated tools put together under one name; this is unlike S,
where all functions are tightly integrated and controlled by the
6) What is S-PLUS? What does it have that S doesn't?
S-PLUS is a cleverly-named version of S sold by Statisti-
cal Sciences, Inc. It contains various extensions to S added
by StatSci, is supported, and has a large installed base. It
tends to track the latest AT&T release, but it is not ``more
recent'' than S itself. StatSci was founded by Douglas Martin.
One can use S-PLUS to do all that one does in S.
The major areas in which S-PLUS extends S are time-series, survival
analysis, `modern regression' (including LMS regression and
projection pursuit regression), classical statistical tests,
graphical device drivers and dynamic loading.
From the s-news digest (8 Jun 1993; digest107):
Information about the S Language Software and S-PLUS can be obtained
from StatSci sales, 1700 Westlake Avenue North, Suite 500, Seattle, Washington
98109, by telephoning 1-800-569-0123 (North America), or 1-206-283-8802;
FAXING 1-206-283-8691; or by using Internet Email at email@example.com.
StatSci also offers a free instructional video explaining advanced, modern
data analysis using S-PLUS Software.