I use the following code snippet to calculate attention weights and get the new hidden state input for my RNN.
 association = torch.mv(hidden_states_other[l], hidden_states[i])
 probs = torch.nn.functional.softmax(association)

 attention_val = torch.mv(torch.t(hidden_states_other[l]), probs)
 hidden_states_weights[i] = attention_val

Running this, gives me the error
RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation

I don’t see any inplace operation. Can someone explain why this is happening?
 hidden_states : N x R tensor
 hidden_states_other : N x R tensor
 l : M, tensor
 hidden_states_weights : N x R tensor