MATLAB: Curve fitting for multiple variable

Question

I am an engineering student and relatively inexperienced with matlab. I have data sets that describe the relation between a dependent variable of interest and six different independent variables,I want to do a fit to define a function that will describe the dependent variable as a function of the six independent variables:

y=f(x1,x2,x3,x4,x5,x6)

Can I do with cftool?

How would I go about doing this? Thanks in advance for any help.

Answer 1

Hi zohre vash,

that depends strongly on what kind of model function you are using. cftool provides a bunch of functions and a GUI in order to control your actions.

If your function is nonlinear you might look into lsqcurvefit.

If you have constraints regarding the datapoints of your model function and your model function is polynomial you might want to try "polyfix" from File Exchange:

https://de.mathworks.com/matlabcentral/fileexchange/54207-polyfix-x-y-n-xfix-yfix-xder-dydx-

If you have a custom function you might look into fmincon and formulate an optimization problem:

https://de.mathworks.com/help/optim/ug/fmincon.html

Kind regards,

Robert