Don, that's a great little mini tutorial, exactly what I was hoping for. I'm looking forward to learning more tricks.<br><br>On an unrelated note, I have an STUArray nbody. I haven't really looked closely at the chris+dons version, but I suspect they amount to doing the same thing. I get commensurate runtimes at least. But I'll post it on the wiki in a while in case there is some optimization I missed.
<br><br>On an even more unrelated note, I get slower runtimes with -optc-O3 and -optc-ffast-math than without. Individually or in tandem. Odd. This is ghc 6.4.1 and gcc 4.0.3 on a (Banias) Pentium M.<br>