Do you mean v0.2.0 or v0.2.2? From a cursory look at the repo, it looks like alloc_threaded_grad was added in 0.2.1, so the UndefVarError makes sense if you wer

Do you mean v0.2.0 or v0.2.2? From a cursory look at the repo, it looks like alloc_threaded_grad was added in 0.2.1, so the UndefVarError makes sense if you were using the older 0.2.0 version.