How can I perform multivariable polynomial curve fitting?

Hey!

I am looking to perform a polynomial curve fit on a set of data so that I get a multivariable polynomial.

I have successfully been able to fit a curve on 2 independent variables using curve fitiing tool. In my case, that was "efficiency as a function of flow rate and head."

I want to be able to perform a fit that gives me a function for something like, "efficiency as a function of flow rate, head and angle." Any ideas?

Thank you!

[Karen Hejazi]

i mean that now i have 3 independent variables.

[Scott MacKenzie]

You can't use the curve fitting tool to build a model with >2 independent variables. But, see this ANSWER for an alternative approach (which I haven't tried but looks reasonably simple).

Answer 1

[Matt J]

polyfitn is pretty popular:

https://www.mathworks.com/matlabcentral/fileexchange/34765-polyfitn?s_tid=srchtitle