how to define 'Y' in fitensemble function (Matlab 2011a)

Question

sani ars 2012-5-22

how we can write Y (parameter of fitensemble function in Matlab 2011a)...

ens = fitensemble(X,Y,'AdaBoostM1',50,'tree');

I have tried to define it buit prompt the error as:

??? Error using ==> ClassLabel>ClassLabel.ClassLabel at 28 You must pass class labels as a vector.

Error in ==> FullClassificationModel>FullClassificationModel.prepareData at 133 allClassNames = levels(classreg.learning.internal.ClassLabel(Y));

Error in ==> FitTemplate>FitTemplate.fit at 167 [X,Y,dataPrepOut{1:this.NDataPrepOut}] = ...

Error in ==> fitensemble at 274 obj = fit(temp,X,Y);

Error in ==> ada_boost_ex1 at 12 ens1 = fitensemble(data,y,'AdaBoostM1',50,'tree');

Answer 1

Wayne King 2012-5-22

If you are doing classification as you are with 'AdaBoostM', then Y should be a categorical variable, character array, or cell array of strings.

So say you have two classes, sick and healthy. Your Y might look like this for 10 measurements.

Y = {'S','S','H','S','H','H','H','S','H','S'};

or

Y = nominal({'S','S','H','S','H','H','H','S','H','S'});