oh yes I forgot to post the trace-back
/usr/local/lib/python3.5/dist-packages/ipykernel_launcher.py:67: RuntimeWarning: divide by zero encountered in double_scalars
RuntimeError                              Traceback (most recent call last)
 in ()
----> 1 scores = dqn()
2
3 # plot the scores
4 fig = plt.figure()
5 ax = fig.add_subplot(111)
 in dqn(n_episodes, max_t, eps_start, eps_end, eps_decay)
23             score += reward
24             #reward = np.tanh(reward)
—> 25             agent.step(state, action, reward, next_state, done)
26             state = next_state
27             if done:
 in step(self, state, action, reward, next_state, done)
57             if np.count_nonzero(self.memory.tree.tree) > self.batch_size:
58                 tree_idx, batch, ISWeights_mb = self.memory.sample(BATCH_SIZE)
—> 59                 self.learn(batch, GAMMA)
60
61     def act(self, state, eps=0.):
 in learn(self, batch, gamma)
114         Q_targets =  rewards + (gamma * Q_targets_next * (1-dones))
115
–> 116         Q_expected = self.qnetwork_local(states).gather(1, actions)
117
118         loss = F.mse_loss(Q_expected, Q_targets)
RuntimeError: invalid argument 4: Index tensor must have same dimensions as input tensor at /pytorch/aten/src/THC/generic/THCTensorScatterGather.cu:16
Thank you for your help