## Contents

## Description of demo_regression_GAM.m

Regression using General Additive Models

clear all close all generateData_3DQuad

## usage of GAM regression with linear regression

options_gam1 = []; options_gam1.subFunc = 'lin'; model_gam1 = ml_regression_GAM(Xtrain, ytrain, options_gam1); yhat_gam1 = model_gam1.predict(model_gam1, Xtest); testError_gam1 = mean(abs(yhat_gam1 - ytest)); fprintf('Averaged absolute test error with %s is: %.3f\n', model_gam1.name, testError_gam1); plotRegression2DPoints(Xtrain, ytrain, model_gam1); view(60,30);

Averaged absolute test error with GAM with Linear Regression is: 0.547

## usage of GAM regression with polynomial of degree 2

options_gam2 = []; options_gam2.subFunc = 'rg'; options_gam2.deg = 2; model_gam2 = ml_regression_GAM(Xtrain, ytrain, options_gam2); yhat_gam2 = model_gam2.predict(model_gam2, Xtest); testError_gam2 = mean(abs(yhat_gam2 - ytest)); fprintf('Averaged absolute test error with %s is: %.3f\n', model_gam2.name, testError_gam2); plotRegression2DPoints(Xtrain, ytrain, model_gam2); view(60, 30);

Averaged absolute test error with GAM with Polynomial Regression of Degree 2 is: 0.268

## usage of GAM regression with smooth cubic splines

options_gam3 = []; options_gam3.subFunc = 'spl'; options_gam3.smoothing = 1.5; model_gam3 = ml_regression_GAM(Xtrain, ytrain, options_gam3); yhat_gam3 = model_gam3.predict(model_gam3, Xtest); testError_gam3 = mean(abs(yhat_gam3 - ytest)); fprintf('Averaged absolute test error with %s is: %.3f\n', model_gam3.name, testError_gam3); plotRegression2DPoints(Xtrain, ytrain, model_gam3); legend view(-60, 30);

Averaged absolute test error with GAM with Smooth Cubic Splines is: 0.250