[plt-scheme] Fractals

Hi Matthew and all,
I'm also using PLT Scheme for a project that involves lots of
floating-point calculation, namely my attempts at
http://recmath.org/contest.

I'm still roughly in the top 10 on the contest despite running on just
one CPU and using the relatively-slow PLT Scheme floating point for
most of the arithmetic.  I credit the fast
development-test-explore-revise cycle for that.  My code is quite
short, quite simple, easy to improve -- not because I'm a good
programmer, but just because of the support that HtDP and PLT give.

But your recent email makes me wonder if I could get a significant
speedup in my central loops by doing something special with my
floating-point numbers ... it also makes me think that it's pretty
hopeless.  Should I write some of those innermost loops in C and then
call them somehow?  (Do you have a reference on how to do that?)

I've done some profiling so I know exactly where my code spends most
of its time (divided almost equally among the innermost loops of
several floating point calculations).

of course there are also ways (by rearranging my data structures, and
using better computational geometry algorithms than the naive ones
I've implemented so far, and so on) that I can get a speedup of a
factor of a few by doing some more work programming in PLT Scheme.

Thanks,
--Joshua