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From Anton Tagunov <>
Subject Re[2]: [math] abstact nonsense was Re: [math][functor] More Design Concerns
Date Thu, 03 Jul 2003 11:18:29 GMT
Hello Mark!


MRD> One idea is it have Custom Iterators. A Custom Iterator could walk
MRD> through the objects in a collection (or the double values in an array)

These iterators would also provide other nice capability,
receiving the values incrementally, "on the fly"
(say, from an InputStream or properly obtained
MySQL result set) w/o having to allocate
intermediate storage for them.


MRD> Then its up to the implementor of the Iterator how "efficient" it works
MRD> with the collection or double[], in the double[] case it can just return the
MRD> value, in the Collection case it may preform a number of tasks prior to 
MRD> returning a value.

Looks like it still has to be decided upon
whether the iterator should return double or Object
does not it?

Are the questions
a) double or Object
b) iterator or not iterator


BTW, probably does the future introduction of Generics (Java 1.5)
promise any opportunities to work with primitive values and yet
have no code duplication (a bit like STL)?


Apologies, if this break-in was totally "the wrong sound",
I certainly lack the knowledge of the current math code
and interfaces, speaking more "in theory" :-)



As for the 'double' vs 'Object' issue, if I ever have to use
a math library I, as an at most purely applied mathematician,
(yup, my diploma says I am, but I really doubt that myself :)
will probably prefer 'double'.

But it's not a qualified opinion, plz disregard it :)

I wouldn't write a separate mail on this as there
already are qualified advocates for both viewpoints!

The Funtor-style approach looks promising but I've got deep
reservations about performance (and yes, that's what C-background
guys will probably think, not only Fortran-background! ;-)

And also if all we need are real value computations,
the 'double' interfaces are probably more "usable",
"user-friendly" and less "scaring".

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