function out = comp_loss(E,loss)

switch loss
    case 'l1'
        out = norm(E(:),1);
    case 'l21'
        out = 0;
        for i = 1 : size(E,2)
            out = out + norm(E(:,i));
        end
    case 'l2'
        out = 0.5*norm(E,'fro')^2;
end

