def choose(self):
    l_max = ([0] * len(self.learners))
    for (i, learner) in enumerate(self.learners):
        l_max[i] = torch.max((learner.U[self.id] @ learner.V.t()))
    return torch.argmax(torch.tensor(l_max))
def choose(self):
    l_max = ([0] * len(self.learners))
    for (i, learner) in enumerate(self.learners):
        l_max[i] = torch.max((learner.U[self.id] @ learner.V.t()))
    return torch.argmax(torch.tensor(l_max))