curve fitting for multiple variable

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.

[Tesfayesus Mamo]

Hi zohre vash,

I dont think cftool can do that, it can only work with two independent variable maximum more than it colapses but what you can do is, you can generate the model equation by using the syntex regress.

Answer 1

[Robert U]

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