Step
Press Step to see the first move.
Load dots
Elbow chart: spread for k = 1 to 8
Look for the elbow: the k where adding more groups stops helping much.
How to play
- Tap or drag to drop dots, or load a set.
- Press Step to watch the two moves one at a time, or Play to run to the end.
- Change k, then check the elbow chart: which k fits best?
| Do this | Phone | Keyboard |
|---|---|---|
| Drop dots | Tap or drag | Arrows move, Space drops (on the field) |
| One move | Step | S |
| Run to the end | Play | P |
| New random start | New start | R |
| Fewer / more groups | k slider | - / + |
| Clear | Clear | X |
What's happening?
- Nobody tells the computer what the groups are. It finds them by itself. That's unsupervised learning.
- It drops k centres (the big markers) at random spots.
- Move 1, assign: every dot joins its nearest centre and takes its colour.
- Move 2, update: every centre jumps to the middle of its dots. The trail shows where it went.
- Repeat until nobody switches. The spread (how far dots are from their centres) can only shrink.
Try this: load Uneven sizes with k = 3 and press Play. Did it find the two small groups? Press New start a few times. Does it always get the same answer?