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PDL::Philosophy -- what's behind PDL?
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This is an attempt to summarize some of the common spirit between
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pdl developers in order to answer the question "Why PDL"? If
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you are a PDL developer and I haven't caught your favorite ideas
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about PDL, please let me know!
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An often-asked question is:
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Why not settle for some of the existing systems like Matlab or IDL
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or GnuPlot or whatever?
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The first tenet of our philosophy is the "free software" idea:
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software being free has several advantages (less bugs because
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more people see the code, you can have the source and port
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it to your own working environment with you, ... and of course,
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that you don't need to pay anything).
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The second idea is a pet peeve of many: many languages like matlab
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are pretty well suited for their specific tasks but for
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a different application, you need to change to an entirely
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different tool and regear yourself mentally. Not to speak about
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doing an application that does two things at once...
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Because we use Perl, we have the power and ease of perl syntax,
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regular expressions, hash tables etc at our fingertips at all times.
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By extending an existing language, we start from a much healthier
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base than languages like matlab which have grown into existence
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from a very small functionality at first and expanded little by little,
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making things look badly planned. We stand by the Perl sayings:
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"simple things should be simple but complicated things should be
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possible" and "There is more than one way to do it" (TIMTOWTDI).
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The third idea is interoperability: we want to be able to use PDL
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to drive as many tools as possible, we can connect to OpenGL or Mesa for
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graphics or whatever. There isn't anything out there that's really
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satisfactory as a tool and can do everything we want easily. And be portable.
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The fourth idea is related to PDL::PP and is Tuomas's personal
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favorite: code should only specify as little as possible redundant
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info. If you find yourself writing very similar-looking code
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much of the time, all that code could probably be generated by a simple
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perl script. The PDL C preprocessor takes this to an extreme.
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=head2 Minor goals and purposes
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We want speed. Optimally, it should ultimately (e.g. with the Perl compiler)
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be possible to compile PDL::PP subs to C and obtain the top vectorized
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speeds on supercomputers. Also, we want to be able to calculate
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things at near top speed from inside perl, by using dataflow to avoid
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memory allocation and deallocation (the overhead should ultimately be only
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a little over one indirect function call plus couple of ifs per
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function in the pipe).
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We want handy syntax. Want to do something and cannot do it easily?
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We want lots of goodies. A good mathematical library etc.
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Copyright(C) 1997 Tuomas J. Lukka (lukka@fas.harvard.edu).
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Redistribution in the same form is allowed but reprinting requires
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a permission from the author.
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Basic/Pod/Philosophy.pod
