Matlab Function Fitting: Tips & Tricks

Jun 30, 2011

Synesthesia

Hello all,

How do people generally fit data in Matlab? I am trying to fit an exponential decay and it doesn't look straightforward. I am looking this up at the moment, but maybe people can give me good answers or starting points here.

Thank you!

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Jun 30, 2011

Synesthesia

Think this is fminspleas

Jun 30, 2011

jhae2.718

Gold Member

I usually use polyfit with the appropriate logarithms.

1. How do I use the "fit" function in Matlab?

The "fit" function in Matlab is used to create a model that fits a given set of data. To use this function, you need to specify the type of model you want to fit (e.g. linear, polynomial, exponential) and the data you want to fit the model to. For example, if you want to fit a linear model to a set of data points stored in the variables x and y, you would use the command "fitlm(x,y)".

2. How can I improve the accuracy of my fitted model in Matlab?

There are several ways to improve the accuracy of a fitted model in Matlab. One way is to increase the number of data points used to fit the model, as this can help to reduce the effects of random noise in the data. Another way is to try fitting different types of models and compare their performance using metrics such as the root mean squared error (RMSE) or R-squared value. Additionally, you can try adjusting the parameters of the model (e.g. changing the order of a polynomial model) to see if this improves the fit.

3. Can I use custom equations to fit my data in Matlab?

Yes, you can use custom equations to fit your data in Matlab. The "fit" function allows you to specify a custom equation as the model to fit. You can also use the "cftool" function to interactively create and fit a custom equation to your data. Additionally, you can define your own custom function and use the "lsqcurvefit" function to fit it to your data.

4. How do I visualize the results of my fitted model in Matlab?

There are several ways to visualize the results of a fitted model in Matlab. One way is to plot the fitted model alongside the original data points to visually compare their fit. You can also use the "plot" function to plot the predicted values of the fitted model over a range of x values. Additionally, you can use the "cftool" function to interactively visualize and explore the results of your fitted model.

5. Can I use the fitted model to make predictions in Matlab?

Yes, you can use the fitted model to make predictions in Matlab. Once you have a fitted model, you can use the "predict" function to generate predicted values for new data points. You can also use the "cftool" function to interactively enter new values and see the predicted output of the fitted model. Keep in mind that the accuracy of these predictions will depend on the accuracy of the fitted model and the quality of the data used to fit it.