tensor([-0.3069, -0.6867, -0.8731])
      >>> torch.logaddexp(torch.tensor([-100.0, -200, -300]), torch.tensor([-1.0, -2, -3]))
      tensor([-1., -2., -3.])
      >>> torch.logaddexp(torch.tensor([1.0, 2000, 30000]), torch.tensor([-1.0, -2, -3]))
      tensor([1.1269e+00, 2.0000e+03, 3.0000e+04])