torch.backends.mps.is_available() Debugging history. Encoder weights not updating → Only occurs with Adam (SGD works fine) → Discovered MPS backend bug with non-contiguous tensor handling.the bug that taught me more about PyTorch than years of using ita loss plateau that looked like my mistake turned out to be a PyTorch bug. tracking it down meant peeling back every layer of abstraction, from optimizer internals to GPU kernels.https://elanapearl.github.io/blog/2025/the-bug-that-taught-me-pytorch/