Curve fitting data from a script model

Hello!!

I have some data that I need to fit. And I have a model with one variable that fits, but I would like Matlab to calculate the fit instead of doing it manually. But when I try to use fit, the fitted curve is far off... I hope you can help me!

The model calculates f for a given x and Mdot. f is also a [6x1]

x = [6x1];
FUN = fittype('model(x,Mdot)');
fo = fitoptions(FUN);
fo.StartPoint = [0.08*Msun/yr];
fit1 = fit(x,f,FUN)
plot(fit1,x,f)

Answer 1

[Star Strider]

We don’t have your data or your model. You may need one more parameter to fit your function to your data.

[Maria Munoz]

When I plot the model function and the data, I get a good fit... And I only use the x and Mdot. I just don't understand why it doesn't work.

[Star Strider]

We don’t know why it doesn’t work either, because we don’t have your data or your model function to experiment with to see what the problem is.

[Maria Munoz]

Sorry, of course! I have a lot of data, but this is one sample of what I need to fit:

f = [1.51526047923861e-11; 1.39617501447364e-11; 1.99836674688087e-11; 1.69039270148481e-11; 1.91708428700862e-11; 1.91244758590242e-11]

x = [0.547965008022000e+15; 0.684005989759400e+15; 0.866866521626200e+15; 1.15498943410500e+15; 1.33682957397900e+15;1.55703596918000e+15]

Thank you so much for your time!! :)

[Maria Munoz]

The model is a bit difficult to share, because there are a lot of constants and it calls other functions... But if you have any idea of why it doesn't work, something I could try, I really don't know... I would be forever thankful!

[Star Strider]

I would like to help, but without your model and an explanation of it, and especially without knowing (and preferably having a mathematical model of) the process that created your data, there is simply no way to go further.

I will delete my Answer in a few minutes.