I haven't been able to stop thinking about that XKCD comic since I read it. It's equal parts depressing and motivating.

How are you calculating fitness?

The fitness is simply the distance traveled to the right. The DNA is made up of segment lengths, with, joint rotation, joint speed and joint offset (when the joints move relative to the other joints)

How do you figure the movement of each joint? I saw some were kind of wobbly.

Sure..and put the rest of us out of business? : ) Although it is interesting to think about what the make-up of the genetic material would be. Just a string of 0s and 1s? CPU opcodes? Or maybe some higher level sub-units.

> Just a string of 0s and 1s? CPU opcodes?

These have been tried. Historically Genetic Algorithms have represented their genotypes as bit strings. Some Genetic Programming systems use CPU instruction strings (pros: fast as heck, cons: can produce indecipherable spaghetti code that breaks when you remove those 400 NOOPs because it's adapted to the cache size of this particular CPU).

> Or maybe some higher level sub-units.

These too. Sometimes as trees of instructions, dataflow diagrams, FSMs and so on.

Very interesting.."indecipherable spaghetti code that breaks when you remove those 400 NOOPs because it's adapted to the cache size of this particular CPU" - sounds a little like our "junk" DNA (though I suspect the analogy breaks down in the details.)

It can get pretty Rube Goldbergesque, apparently. The main rule of thumb is that if you're doing GP with CPU strings as your representation, beware of including run time in the fitness function. Because you will almost inevitably get over adaptation that breaks on any other platform.

GP would just turn all the programmers to digital shepherds :P

It would be a really interesting challenge to get broad enough coverage in the fitness function that things like the previously-mentioned "400 NOPS" don't cause problems.

Besides unit (or otherwise) tests, it should also be possible to use static analysis to measure fitness and/or use a static type system to restrict the possibilities. I'd think this would have some of the same problems, though- anybody know of any work on that?

> It would be a really interesting challenge to get broad enough coverage in the fitness function that things like the previously-mentioned "400 NOPS" don't cause problems.

All the branches of evolutionary computing agree that evolved systems are really good at finding flaws in your problem statements. Most of the evolved systems you see in production are not the product of the first attempt to evolve the system.

> Besides unit (or otherwise) tests, it should also be possible to use static analysis to measure fitness and/or use a static type system to restrict the possibilities. I'd think this would have some of the same problems, though- anybody know of any work on that?

Type consistency for GPs is a whole subfield in itself. See the textbook I referred to, it has a chapter on it from memory.

This is something I would be interested in using. Right now we use either email or Google docs. I drive to the grocery store and my wife puts together a list and beams it to my phone.

What would the process be for sharing a list created on the web with a mobile device? Emailing the generated URL? I don't see an option to send an SMS with the URL. Can users sign up for updates when a list is changed?

Thanks for checking it out! And yes - just send the URL to your phone via sms/email/etc, the UI is designed to work well on mobile.

No apps, no sharing creds, just a URL that will have the latest list no matter what device you're on :)

Seems that most (all?) of the start-up developer job openings posted on HN are based in SV. I wonder if there is another site like HN for NYC start-ups to advertise positions.