Re: OO versus RDB

From: Daniel Parker <danielaparker_at_gmail.com>
Date: 8 Jul 2006 14:22:37 -0700
Message-ID: <1152393757.084562.244430_at_35g2000cwc.googlegroups.com>


H. S. Lahman wrote:

> >
> > I'm not sure what the "algorithmic functional decomposition
> > hierarchies" would be for, say, a matrix LP decomposition problem.
> > Textbook mathematical problems that have a recursive structure can
> > sometimes be represented very cleanly in an FPL, but solutions with
> > good numerical properties are often much less clean, and are more
> > easily attacked with imperative techniques.
>
> I've written an LP package so trust me that there is a lot of code
> beyond basic matrix operations like transpose. For example, many such
> packages use heuristics to find an initial basic feasible solution and
> that is nontrivial. There's also infrastructure code for things like
> switching between Primal/Dual solutions. The real meat of the algorithm
> lies in deciding which matrix operations to do and when to do them.
> Performance demands that those decisions be kept simple, but there is
> still a lot of stuff going besides text book matrices operations.
>
> [There is an analogy in practical Quicksort implementations. The basic
> text book Quicksort algorithm can probably be encoded in roughly a dozen
> lines of C. However, any commercial grade library Quicksort
> implementation will likely have a hundred lines or so (e.g., to use a
> more efficient sort once partitions are small).]
>
Perhaps more to the point, the textbook Quicksort can be implemented in a few lines in a functional language, but a robust implementation can take a hundred lines plus in a non-functional language like C or FORTRAN. Daniel Received on Sat Jul 08 2006 - 23:22:37 CEST

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