PDL::Intro - Introduction to the Perl Data Language
Version 2.0
"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]
Perl is an extremely good and versatile scripting language, well suited to beginners and allows rapid prototyping. However until recently it did not support data structures which allowed it to do fast number crunching.
However with the development of Perl v5, Perl acquired Objects. To put it simply users can define their own special data types, and write custom routines to manipulate them either in low level languages (C and Fortran) or in Perl itself.
This has been fully exploited by the PDL developers. 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
$a=$b+$c
$b
$c
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.
As well as the PDL modules, that can be used by normal perl programs, PerlDL comes with a command line perl shell, called perldl, which supports command line editing. In combination with the various PDL graphics modules this allows data to be easily played with and visualised.
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:
Quick summary - PDL for the impatient
The Frequently Asked Questions list for PDL.
Why another matrix language?
An introduction to using smart indices in PDL.
The all important slicing of piddles.
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.
To install PDL, copy and paste the appropriate command in to your terminal.
cpanm
cpanm PDL
CPAN shell
perl -MCPAN -e shell install PDL
For more information on module installation, please visit the detailed CPAN module installation guide.