AI engineering glossary · Calculus optimisation
What is level set?
Level set (also called Contour line): The set of all inputs at which a function takes one fixed value. In two dimensions these are contour lines, like height contours on a trekking map. The gradient is always perpendicular to the one passing through a point, which helps visualise a loss landscape.
Level set: an example
For f(x, y) = x^2 + y^2, the level set f = 25 is a circle of radius 5 centred at the origin.
Related terms
More Calculus optimisation terms
- Levenberg-Marquardt algorithm
- Limit
- Line search
- Linear approximation
- Linear programming
- Lipschitz continuity
- Local minimum
- Loss landscape
Where you learn it
Level set is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.