Epoch
Loss
Tap to add dots
Activation
How to play
- Pick Red dot or Blue dot, then tap the plot.
- Press Play and watch the colours settle.
- Try a preset, or change the layers and neurons.
| Do this | Phone | Keyboard |
|---|---|---|
| Add a dot | Tap the plot | Arrows, then Enter |
| Remove a dot | Tap the dot | Enter on it |
| Swap colour | Red / Blue | C |
| Play / Pause | Play | P |
| One step | Step | N |
| New random start | Reset | R |
What's happening?
- Each neuron adds up its inputs, each times a weight, then squashes the total.
- At first the weights are random, so the guesses are random too.
- The loss is a score for how wrong the guesses are. Lower is better.
- Each epoch, the net nudges every weight a little in the direction that lowers the loss. That's backpropagation.
- The soft background is the net's guess for every spot. The bright line is where it flips from red to blue.
- One neuron can only draw a straight line. Stacking neurons lets the net bend lines into curves.
Try this: load Spiral, set 1 layer of 2 neurons and press Play. Stuck? Now add layers and neurons until it wins.