PDL::Intro - Introduction to the Perl Data Language

- NAME
- DESCRIPTION
- SYNOPSIS
- AUTHOR

# NAME

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]

# DESCRIPTION

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 PerlDL 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 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.

# SYNOPSIS

This manual page provides a general introduction to the underlying philosophy of PDL and practical examples on how to use it. For details, see:

the PDL::Intro manpage
  This document

the PDL::Impatient manpage
  Quick summary - PDL for the impatient

the PDL::Philosophy manpage
  Why another matrix language?

the PDL::Indexing manpage
  An introduction to using smart indices in PDL.

the PDL::Slice manpage
  A reference guide to the same.

the PDL::PP manpage
  A utility for generating extension in C language for use with PDL easily.

the PDL::FAQ manpage
  The Frequently Asked Questions list for PDL.

the PDL::Tips manpage
  Small tips and tricks for writing idiomatic PDL code.

the PDL::Internals manpage
  How does it all work?

the PDL::Dataflow manpage
  Tuomas has been too lazy to document this yet.

# AUTHOR

Copyright (C) Karl Glazebrook (karlglazebrook@yahoo.com), Tuomas J. Lukka, (lukka@husc.harvard.edu) and Christian Soeller (c.soeller@auckland.ac.nz) 1997 to 2000. Commercial reproduction of this documentation in a different format is forbidden.