# Quantile regression for non linear regression analysis?

I am new to quantile regression, I have read the original paper from Koenker and Bassett and also other documents.

I was under the impression that quantile regression is only used with linear regression functions, but after reading this I am confused:

https://mathematicaforprediction.wordpress.com/2013/12/23/quantile-regression-robustness/

The author seems to imply that he can calculate quantile regression for any curve.

Is quantile regression also used with other types of functions other than linear?

Simply use whatever form of nonlinear function of the parameter vector $\beta$ , namely $f(\beta)$, you have in place of $X\beta$ in https://en.wikipedia.org/wiki/Quantile_regression#Conditional_quantile_and_quantile_regression . Of course, if $f(\beta)$ is a nonlinear function of the parameter vector $\beta$, the quantile regression problem will not be a Linear Programming problem, but it could still be solved with an appropriate nonlinear optimization solver.