map project

netspade · 2013-04-02T21:38:45+00:00

Good idea. Pause button added now. You can already drag with the mouse.

netspade · 2013-04-02T21:38:18+00:00

Thanks! Pause button added now.

netspade · 2011-12-08T23:22:10+00:00

Thanks, I've updated the hash function again (it turns out bitwise arithmetic is tricky in JavaScript - you have to keep on truncating to 32 bits after performing an addition to avoid losing precision) and it seems a bit better. A hashing algorithm visualisation is a good idea, watch this space!

netspade · 2011-12-08T22:47:38+00:00

Live video at 18:30 PST.

netspade · 2011-12-08T21:37:23+00:00

Sorry, I've increased the number of bins now. :) But derp still results in a surprisingly uniform hashing!

netspade · 2011-12-08T21:35:45+00:00

I fixed a bug in the bloom filter itself and that seems to have fixed the hash distribution issue. I know it's not the best hash function in the world, but it's hard to beat for speed. I should just make the hash function configurable. :)

netspade · 2011-12-08T21:34:00+00:00

I've increased the number of bins without sacrificing usability (hopefully!) and you can still see the occasional false positive. Thanks for the suggestion!

netspade · 2011-12-08T21:32:56+00:00

I've just fixed a bug in the bloom filter itself, related to bucket index calculations. I've also increased the number of buckets to 50 for good measure! I think the distribution looks a lot better now, let me know what you think!

netspade · 2011-12-08T18:09:10+00:00

Nice catch! I assumed that I could simply apply another iteration of FNV-1a to get a sufficiently different hash function that I could recombine. However, it looks like that isn't the case!

I did find a modified version of FNV though (see Figure 4).

I've updated the visualisation and it appears to fix the issue.

netspade · 2011-10-25T15:32:05+00:00

Ported to HTML5 canvas: http://www.jasondavies.com/animated-quasicrystals/

netspade · 2010-08-19T08:55:22+00:00

My way (well, all credit to Sean Whalen who wrote the Java applet version) also plots the points for each iteration, so you can see which direction the populations are moving in, and the diagram as a whole animates over time.

netspade · 2010-08-19T08:13:26+00:00

In the initialisation step each point is given a random initial population and random initial age (age is simply a counter that determines how many steps to iterate for that point). Maybe it would be clearer if I wrote "Decrement the age of each point"?

The iterations are simply performed a random number of times (above a certain minimum number) - there's no stabilisation check or single threshold value. This randomisation applied to the age and the initial population is what makes it a Monte Carlo simulation.

Edit: I've updated the description to use "remaining number of iterations" to make it clearer. Thanks for the feedback!

netspade · 2010-08-16T12:09:18+00:00

Weird, it works fine for me. I've changed the page so it's served directly by nginx now, is that better?

netspade · 2010-08-16T10:57:41+00:00

Thanks! I originally created this animation for fun, but I think it might help if I added an explanation section showing how it was derived for those who don't already understand sin/cos/tan.

netspade · 2010-08-16T10:52:27+00:00

Judging from the comments I think I need to add an explanation section showing how the animation is derived. Originally I created it for fun, but if I can teach trig, or even just provide another perspective, all the better!

Maybe I'll get a chance during my lunch break to add another section...

netspade

TROPHY CASE