Tuesday, May 19, 2009

Happy Modification Of Most Sigificant Digit In Base 10 Representation Day!

I didn't even think to comment when the MSB in base 2 changed. What kind of a NERD am I?

Once my average catches up with the daily weigh-in, I'll be Officially At My (Original) Goal. I think I'm going to aim at another 10 lbs, though.

In other news, I've been messing around with Haskell, but I need a real programming project to really do something. I was thinking about this again.

I realized yesterday that it's not just hard but actually logically impossible to represent a mechanical object physically as a strict tree. Consider even just a triangle of beams. Two of them attach, making them children of the same parent (the joint). The third attaches to both, which is illegal.

A commenter suggested the netlist approach that electronic simulators take. The problem is that the netlist is a genome of the device. I have to be able to take a subset of the genome and swap it out for another piece that also has to drop in place. How does that work without leaving dangling "wires"? I could just leave them there for Nature to work out, but is that going to make success too infrequent for me to have patience for?

I think my algorithmic approach could work. But I haven't really worked it out. In any case, Haskell (or possibly better yet, Tcl or Lisp) is probably a good match. These languages already allow you to run data as code and treat code like data easily. Actually, now that I think about it, I'm not sure Haskell does that. What is that property even called?

Tuesday, May 5, 2009


  • Continuing an Obsolete Technology theme from my last entry, I got a mechanical alarm clock at the flea market. All the parts worked, but it lost 5-10 minutes over a 12 hour period, at which point it would stop.

    I got a couple old-timey clock repair books at the library for tips on what to clean and/or adjust. Now it actually gains 2-3 minutes in 24 hours, but I recentered the little adjusty lever, so I should be able to make it keep good time. Unfortunately it still alarms 10 minutes before the set time. Also, it sounds like a fire alarm, which is maybe not the ideal thing to wake up only a single person at 5:30 am.

  • Could have used this site years ago. Or is there a way to put MathML on Blogger now? If not, I guess I should learn LaTeX.


  • While looking forward to LogiComix, I came across Uncle Petros and the Goldbach Conjecture. Fun, short read. I already knew about the Goldbach Conjecture, but the book gave me an idea for a possible disproof that probably doesn't work. First, the Conjecture: All even numbers > 2 can be expressed as the sum of two primes. One way to disprove this would be to find a number n such that no numbers from n to 2n are prime. There is already a theorem that proves that you can construct a "prime gap" of any size, so one of length n is no problem. The reason this doesn't quite work is that you also have to specify that the gap starts at n. Oh wait, it's even worse than that. There's a prime between n and 2n for all n. Pffff.
  • You know what would be a killer app? Online WINE/Crossover. I could upload a Windows/OSX app and install it on a virtual machine and then interact with it via a generated Flash interface. I guess the only really hard part of this is the "generated Flash interface". Kind of like those programs that let me display on another computer (like X-Windows, but for all OSes) where the "another computer" is "a Flash app".