On Firefox here, the "Save Local Population" option seems to crash. Any idea why that might be happening? (Amazing site btw - every time it pops up I end up spending much too long with it).
As internet distractions go, the original was one of the most memorable I ever came across. A friend and I used to leave them running over lunch and see who was winning when we got back.
Thanks for the fun :-)
It seems to always get into a rut where one design lucks out and dominates generation after generation, with no mutations producing anything even close to working. Like, the top ten don't change after hundreds of generations. Maybe this is just an attribute of genetic algorithms. They quickly zero in on something kind of good, and then get stuck at this local maxima. Or maybe I need to just play around with the Mutation Rate and Mutation Size settings.
In general, one should keep the mutation rate really low to allow the population slowly change over time. High mutation rate will lead to local optima quickly but also very hard to get out. Low mutation rate will require significant more generations but in general result in better adaptation.
It seems like more should change than just the shape. I'd wager that a slower car with more power may be less likely to get stuck in ruts. But it seems that the power and speed don't vary, just (barely, after a few generations) the shape.
Edit, I scrolled down and it covers the genome:
• Shape (8 genes, 1 per vertex)
• Wheel size (2 genes, 1 per wheel)
• Wheel position (2 genes, 1 per wheel)
• Wheel density (2 genes, 1 per wheel) darker wheels mean denser wheels
• Chassis density (1 gene) darker body means denser chassis
It basically lands on a two-wheeled medium-bodied shape and doesn't seem to make much progress after that. Power and speed would be interesting variations.
What happens in an evolutionary algorithm depends on what you write it for. This is a fun toy, but what it does specifically is explore a very limited simulation of evolution by natural selection. Metaheuristics aimed at optimization have a lot of techniques aimed at not stalling out on a prematurely converged design, as well as improving other desirable properties of the population, at the expense of any pretense of fidelity to real-world evolution processes.
This is why I said it needed crossover and got downvoted into oblivion :) turns out it at least tries to have crossover, so maybe the genome doesn't translate to crossover doing anything relevant.
I wasn't fooling. Think about it for a second, if your process involves a lot of crossover that means large sections of working genome will be passed on. If the ONLY mechanism for changing anything is mutation, then mostly you're just breaking what works.
That's what you're describing, so I'd look at how the genome is constructed to understand why it's not doing more.
this is fun, even though the speed controls aren't super intuitive. You can press "Surprise" to speed things up and go through a bunch of iterations quickly.
The mutation rate (likelihood that g changes) and mutation size (Δg) are fun hyperparameters to tweak while watching the population evolve over time.
It would be interesting to see a gene for "compliance" so the cars could have some kind of suspension. EVerything more or less evolved into a sort of tron-bike shape for most of the runs I tried.
> EVerything more or less evolved into a sort of tron-bike shape for most of the runs I tried.
I ran it in the background for a very high mutation rate for a long time and it managed to come up with something very different---a little wheel attached to a big wheel, which bounces around and goes over all the obstacles.
...and apparently all the suspension parameters stripped out for some bizarre reason.
The physics simulation clearly uses inelastic collisions, which is wildly unrealistic and why so many otherwise passable 'cars' don't pass the course. Also seems to use a very low coefficient of friction - most of my cars couldn't make it up a two-segement slope.
This html5 version has also been around for longer than a decade already. It's what inspired me to take a class on Genetic Algorithms and Evolutionary Computing in university back then.
The simulation that these cars are driving in has no third dimension for the vehicle to fall over into (or where to put another pair of wheels). So, like a traditional four-wheeled car, these vehicles do not tip over at 0 velocity. I think that property is enough to qualify their behaviour as more similar to four-wheeled cars than motorbikes.
Still runs in the browser thanks to Ruffle:
https://peteshadbolt.co.uk/posts/ga/
Or perhaps, 20 years? ;-)
There were a few genetic algorithm "polygons approximate picture" pages back in that era as well.
Deleted Comment
It happened to crocodiles and it could happen to you too.
Edit, I scrolled down and it covers the genome:
• Shape (8 genes, 1 per vertex)
• Wheel size (2 genes, 1 per wheel)
• Wheel position (2 genes, 1 per wheel)
• Wheel density (2 genes, 1 per wheel) darker wheels mean denser wheels
• Chassis density (1 gene) darker body means denser chassis
It basically lands on a two-wheeled medium-bodied shape and doesn't seem to make much progress after that. Power and speed would be interesting variations.
I wasn't fooling. Think about it for a second, if your process involves a lot of crossover that means large sections of working genome will be passed on. If the ONLY mechanism for changing anything is mutation, then mostly you're just breaking what works.
That's what you're describing, so I'd look at how the genome is constructed to understand why it's not doing more.
The mutation rate (likelihood that g changes) and mutation size (Δg) are fun hyperparameters to tweak while watching the population evolve over time.
It would be interesting to see a gene for "compliance" so the cars could have some kind of suspension. EVerything more or less evolved into a sort of tron-bike shape for most of the runs I tried.
I ran it in the background for a very high mutation rate for a long time and it managed to come up with something very different---a little wheel attached to a big wheel, which bounces around and goes over all the obstacles.
https://news.ycombinator.com/item?id=5942757 (664 points | Jun 2013 | 169 comments)
https://news.ycombinator.com/item?id=10600486 (162 points | Nov 2015 | 57 comments)
https://news.ycombinator.com/item?id=2196747
The physics simulation clearly uses inelastic collisions, which is wildly unrealistic and why so many otherwise passable 'cars' don't pass the course. Also seems to use a very low coefficient of friction - most of my cars couldn't make it up a two-segement slope.
https://web.archive.org/web/20240428203838/http://boxcar2d.c...
Where I come from, we call two-wheeled automobiles motorbikes. Very cool simulation though!
It inspired me to experiment with a genetic algorithm in "Self-parking car evolution":
https://trekhleb.dev/self-parking-car-evolution/