net = feedforwardnet([10 20]); % 2 hidden, 1 output layers
% specify the transfer function as you want
% Usually, layer1 will not be pureli
net.layers{1}.transferFcn = 'tansig'; % hidden layer 1
net.layers{2}.transferFcn = 'tansig'; % hidden layer 2
net.layers{3}.transferFcn = 'purelin'; % output layer
net