Hi all,
I am new to Pytorch and machine learning and I recently tried to run https://github.com/matthew-zhu/MACC-RL/blob/master/DQN-loc.py and i am constantly getting the following error:
Line 141: reward_batch = torch.cat(batch.reward)
RuntimeError: Expected object of scalar type Long but got scalar type Int for sequence element 1 in sequence argument at position #1 ‘tensors’
I tried to find its solutions for half a day but still no luck 
From reading different posts (i.e. https://github.com/rusty1s/pytorch_cluster/issues/19), I believe this error occurred because I am running Windows 10? Has anyone encountered this issue and how to resolve it?
Python: 3.7
Torch: 1.4.0+cu92
What type is batch.reward? If it’s a list, could you check if all tensors have the same dtype?
Based on the error message it seems that some tensors might be stored as IntTensors while others might be LongTensors.
If that’s the case, convert them to the same type via tensor.int() or tensor.long().
Hi @ptrblck,
Yes. The batch.reward is an array/tuple of tensors. Some of the tensors have dtype = torch.int32 and some has dtype = torch.int64.
I just want to have all tensors in batch.rewards as Int. Am i doing this correct as shown below?
count = 0
For single_reward in batch.reward:
{if count == 0: reward_tuple = single_reward.int()
else: reward_tuple = torch.cat([reward_tuple, single_reward.int()], dim=0) #add tensor to tuple
count= count + 1 }
batch.reward = reward_tuple
Your code should be working. Alternatively to concatenating the new data to the same tensor, you could also store all transformed tensors in a new list and transform it to a tensor afterwards.
