Get surface fitting equation with 'lowess'

Hello, I used 'lowess' surface fitting method and got the surface. However, I need to get the equation for the surface so that I can use it to calculate different inputs. Could anyone help on this problem ? Thank you!

Answer 1

[Elodie Jacquemin]

I have the exactly same question. I need it to add it to my derivates... Any help?

[Li Yang]

For 'lowess', there seems not an explicit equation as we would expect(as far as what I searched in google). I changed to 'poly' and got the equation instead.