PHILOSOPHY(1)						User Contributed Perl Documentation					     PHILOSOPHY(1)

NAME

       PDL::Philosophy -- what's behind PDL?

DESCRIPTION

       This is an attempt to summarize some of the common spirit between pdl developers in order to answer the question "Why PDL"? If you are a
       PDL developer and I haven't caught your favorite ideas about PDL, please let me know!

       An often-asked question is: Why not settle for some of the existing systems like Matlab or IDL or GnuPlot or whatever?

       Major ideas

       The first tenet of our philosophy is the "free software" idea: software being free has several advantages (less bugs because more people
       see the code, you can have the source and port it to your own working environment with you, ... and of course, that you don't need to pay
       anything).

       The second idea is a pet peeve of many: many languages like matlab are pretty well suited for their specific tasks but for a different
       application, you need to change to an entirely different tool and regear yourself mentally. Not to speak about doing an application that
       does two things at once...  Because we use Perl, we have the power and ease of perl syntax, regular expressions, hash tables etc at our
       fingertips at all times.  By extending an existing language, we start from a much healthier base than languages like matlab which have
       grown into existence from a very small functionality at first and expanded little by little, making things look badly planned. We stand by
       the Perl sayings: "simple things should be simple but complicated things should be possible" and "There is more than one way to do it"
       (TIMTOWTDI).

       The third idea is interoperability: we want to be able to use PDL to drive as many tools as possible, we can connect to OpenGL or Mesa for
       graphics or whatever. There isn't anything out there that's really satisfactory as a tool and can do everything we want easily. And be por-
       table.

       The fourth idea is related to PDL::PP and is Tuomas's personal favorite: code should only specify as little as possible redundant info. If
       you find yourself writing very similar-looking code much of the time, all that code could probably be generated by a simple perl script.
       The PDL C preprocessor takes this to an extreme.

       Minor goals and purposes

       We want speed. Optimally, it should ultimately (e.g. with the Perl compiler) be possible to compile PDL::PP subs to C and obtain the top
       vectorized speeds on supercomputers. Also, we want to be able to calculate things at near top speed from inside perl, by using dataflow to
       avoid memory allocation and deallocation (the overhead should ultimately be only a little over one indirect function call plus couple of
       ifs per function in the pipe).

       We want handy syntax. Want to do something and cannot do it easily?  Tell us about it...

       We want lots of goodies. A good mathematical library etc.

AUTHOR

       Copyright(C) 1997 Tuomas J. Lukka (lukka@fas.harvard.edu).  Redistribution in the same form is allowed but reprinting requires a permission
       from the author.

perl v5.8.0							    1999-12-09							     PHILOSOPHY(1)