This is something I should probably have included in my params: I’m using pytorch 1.6.0. However, your example runs in Colab and my environment successfully when using pytorch 1.6.0 (the problem must be in some other part of my code). These are my versions:
2021-08-10 09:36:14,511 NN-Training INFO: - PyTorch version: 1.6.0
2021-08-10 09:36:14,511 NN-Training INFO: - Ignite version: 0.4.6

I’ll try with my code in the Google Colab and let you know if I could reproduce the problem.
Thanks!