what is the syntax to add noise in data set

I need the syntax to add noise to data set..

I hv write the code as:

rand_class_data = randsample(data(:,:),data*10/100);

y(rand_class_data)= ~y(rand_class_data);

wrong_labels = y;

%testing ensemble on noised data

losswith_noised_data = loss(ens_on_traindata, rand_class_data,wrong_labels)

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the dataset im using is ''ionosphere'

I want to change the labels that i hd done with

y(rand_class_data)= ~y(rand_class_data);

but the problem is with data

i.e. how should i randsample the data??..

mean to say how to write

r = randsample(data(:,:),data*10/100);

the error is as :

"POPULATION must be a vector."

plz suggest me the right syntax to randsample the data

Answer 1

[Andrei Bobrov]

may be using data(:)?

eg

rand_class_data = randsample(data(:),round(numel(data)*10/100))

[sani ars]

yes .... u r right..... Actually my code is as follows:

data_set = load('ionosphere.txt');

data = data_set(:,1:end-1);

y = data_set(:, end);

train_data = data(1:2:end,:);

train_labels = y(1:2:end);

test_data = data(2:2:end,:);

test_labels = y(2:2:end);

then I had construct an ensemble by using training data as follows:

ens_on_traindata = fitensemble(train_data,train_labels,'AdaBoostM1',100,'tree','type','classification');

then determine then loss (misclassification) of the test data by using the ensemble i.e tested the performance of ensemble on test data as follows:

Losswith_test_data = loss(ens_on_traindata, test_data, test_labels);

Now I wants to analyze the sensitivity of AdaboostM1 and evaluate its performance in the presence of noise..... So thats why I have introduced the noise (classification noise) in the dataset by changing the labels of 10 % of the dataset....

In the Help of MATLAB 2011a, they have added the noise in the artificial dataset...... I tried to use the same with ionosphere dataset, but the problem is with the syntax i.e. in what way I should write the data..

and how to write the randsample( , );

plz can u help me in this regard..??

Answer 2

[Walter Roberson]

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