INTRO(1) User Contributed Perl Documentation INTRO(1)NAME
PDL::Intro - Introduction to the Perl Data Language
Version 2.4
"Why is it that we entertain the belief that for every purpose odd
numbers are the most effectual?" - Pliny the Elder.
Karl Glazebrook [karlglazebrook@yahoo.com] and Craig DeForest
[deforest@boulder.swri.edu
DESCRIPTION
Perl Data Language (PDL) is a perl extension that is designed for
scientific and bulk numeric data processing and display. It extends
perl's syntax and includes fully vectorized, multidimensional array
handling, plus several paths for device-independent graphics output.
"pdl" is an interactive command shell that is supplied with PDL; for
more information, see perldl(1).
Because PDL is a modular extension to perl, it is accessible to
ordinary perl scripts: to write a command-line PDL script you just say
"use PDL;" at the top of an ordinary perl script. There is also a
specialized interactive shell (perldl(1)) that allows you to issue PDL
commands interactively and that includes a path-based subroutine
autoloader similar to those found in MatLab and IDL (which are
trademarks of MathWorks and Kodak, respectively). The perldl shell
allows you to quickly manipulate and "play with" your data. (You can
also invoke it with the shorter command "pdl").
The "PDL" module is a complete Object-Oriented extension to Perl
(although you don't have to know what an object is to use it) which
allows large N-dimensional data sets, such as large images, spectra,
time series, etc to be stored efficiently and manipulated en masse.
For example with the PDL module we can write the perl code "$a=$b+$c",
where $b and $c are large datasets (e.g. 2048x2048 images), and get the
result in only a fraction of a second.
PDL variables (or piddles as they have come to be known) support a wide
range of fundamental data types - arrays can be bytes, short integers
(signed or unsigned), long integers, floats or double precision floats.
And because of the Object-Oriented nature of PDL new customised
datatypes can be derived from them.
Perl is an extremely good and versatile scripting language, well suited
to beginners, and allows rapid prototyping. The PDL extensions to the
language use Perl's object-oriented capabilities to seamlessly add
high-speed scientific capabilities that are themselves written in perl,
C and/or FORTRAN as appropriate -- so your code's "hot spots" run at
native compiled-language speed, while you work in the higher level perl
language (which itself runs faster than many other JIT-compiled or
interpreted languages).
External modules that have been incorporated into PDL include the
complete Gnu Scientific Library; CFITSIO for FITS file handling; FFTW;
the Slatec matrix-handling package; and the PGPLOT, PLPLOT, Karma, and
OpenGL graphics libraries. Ancillary packages written in PDL itself
include image handling, curve fitting, matrix manipulation, coordinate
transformation, nonlinear data resampling, graphics I/O, and extensive
file I/O utilities. Because PDL programs are "just" perl with
additional modules loaded, the entire CPAN archive is also available to
your PDL scripts.
SYNOPSIS
This manual page provides a general introduction to the underlying
philosophy of PDL. For an overview over the rest of the documentation
see PDL::Index. As a beginner the following documents are particulary
recommended:
PDL::Impatient
Quick summary - PDL for the impatient
PDL::FAQ
The Frequently Asked Questions list for PDL.
PDL::Philosophy
Why another matrix language?
PDL::Indexing
An introduction to using smart indices in PDL.
PDL::NiceSlice
The all important slicing of piddles.
AUTHOR
Copyright (C) Karl Glazebrook (karlglazebrook@yahoo.com), Tuomas J.
Lukka, (lukka@husc.harvard.edu) and Christian Soeller
(c.soeller@auckland.ac.nz) 1997-2002.
Commercial reproduction of this documentation in a different format is
forbidden without permission.
perl v5.10.0 2006-03-16 INTRO(1)
