Hi Tobenna,
I understand that being unable to use the inbuilt metrics you want to find a way to calculate RMSE, R-squared and p-values from your code. Refer to the following code for doing the same:
% Calculate RMSE (Root Mean Square Error)
RMSE = sqrt(mean(residuals.^2));
% Calculate R-squared
SSR = sum((yPredict - mean(yActual)).^2); % Regression sum of squares
SST = sum((yActual - mean(yActual)).^2); % Total sum of squares
R2 = SSR / SST;
Lastly, for p-values, you would typically need to use linear regression models or other models that provide statistical tests for variable significance. GPR doesn't inherently provide p-values because it's not a linear regression model.
Hope this helped,
Regards,
Anurag
