kneed¶

Knee-point detection in Python

kneed is a Python library for detecting knee (elbow) points in curves using the Kneedle algorithm. Given a set of x and y values, it identifies the point of maximum curvature — the "knee" or "elbow" of the curve.

Summary of curve and direction arguments

Key Features¶

Knee and elbow detection for concave and convex curves
Increasing and decreasing function support
Automatic shape detection with find_shape()
Multiple knee detection via online mode
Tunable sensitivity parameter (S) for fine-grained control
Multiple interpolation methods — interp1d and polynomial
Built-in plotting for quick visualizations

Quick Example¶

from kneed import KneeLocator, DataGenerator

x, y = DataGenerator.figure2()
kl = KneeLocator(x, y, curve="concave", direction="increasing")

print(kl.knee)    # 0.222
print(kl.knee_y)  # 1.897

Interactive App¶

Explore kneed parameters interactively with the Streamlit app:

ikneed interactive app

Citation¶

If you use kneed in your research, please cite:

Satopa, V., Albrecht, J., Irwin, D., and Raghavan, B. (2011). "Finding a 'Kneedle' in a Haystack: Detecting Knee Points in System Behavior." 31st International Conference on Distributed Computing Systems Workshops, pp. 166-171.