How to find error between predicted and actual data ?

I have trained a model using GPR and want to see error between predicted and actual data.

Answer 1

[Adam Danz]

Use predict(grpModel, x) to get the predicted response. x should be the x values of your training data. Then just subtract the predicted results from the y-values from your training data.

This page of the documentation has a demo. Search for "Compute the regression error on the test data."