function [trainvec,trainlab,testvec,testlab] = createData (napp,ntest,type,d)

if type==1 % boule
    trainvec = randn(napp,d);
    testvec = randn(ntest,d);
    trainlab = ones(napp,1);
    trainlab(trainvec(:,1).^2+trainvec(:,2).^2<1) = -1;
    testlab = ones(ntest,1);
    testlab(testvec(:,1).^2+testvec(:,2).^2<1) = -1;
elseif type==2 % damier 2D, mélange (d>0) ou non (d<=0)
    sigma = d;
    trainvec=[];
    trainlab=[];
    nb=floor(napp/16);
    for i=-2:1;
        for j=-2:1;
            trainvec=[trainvec; [i+(1+sigma)*rand(nb,1) j+(1+sigma)*rand(nb,1)]];
            trainlab=[trainlab; (2*rem((i+j+4),2)-1)*ones(nb,1)];
        end;
    end;
    testvec=[];
    testlab=[];
    nb=floor(ntest/16);
    for i=-2:1;
        for j=-2:1;
            testvec=[testvec; [i+(1+sigma)*rand(nb,1) j+(1+sigma)*rand(nb,1)]];
            testlab=[testlab; (2*rem((i+j+4),2)-1)*ones(nb,1)];
        end;
    end;
end