PPolySim OS
Use case · powered by k-Nearest Neighbors

k-Nearest Neighbors for a decision tree

Simulate a decision tree live in your browser. This runs the real k-Nearest Neighbors solver — adjust the inputs, watch it respond instantly, and export the result. No install, no account.

k-Nearest NeighborsLive

Controls

Presets

k-NN classifies a point by majority vote of its k nearest labeled neighbors. Small k gives jagged, overfit boundaries that chase noise; large k smooths them out but can blur real structure. It is the simplest possible classifier — no training at all. Educational tool.

▶ Run in Python

Data Inspector

Neighbors5
Boundarybalanced

Governing equation

Reading this result: k = 5 sits in the sweet spot: enough neighbors to shrug off noise, few enough to keep the true boundary shape.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

or unlock everything with Pro →

About this simulation

The full k-Nearest Neighbors tool models a decision tree with the same numerics engineers and scientists use — running entirely client-side. Change any parameter and the result updates in real time, so you can build intuition, check a design, or teach the concept without spreadsheets or installs.

More you can do with k-Nearest Neighbors

Other ways to simulate a decision tree

Frequently asked questions

How do I simulate a decision tree?
Open this page and use the live k-Nearest Neighbors tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.
Is it free?
Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.
Can I use my own numbers?
Absolutely — every input is adjustable, and with data import you can drive a decision tree from your own measurements.