rohitg00/ai-engineering-from-scratch · error · ValueError

unknown op {op}

Error message

unknown op {op}

What it means

Error "unknown op {op}" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/76-collective-ops-from-scratch/code/main.py:229

    dtype = getattr(torch, dtype_str)
    tensor = torch.frombuffer(bytearray(tensor_bytes), dtype=dtype).reshape(shape).clone()
    if op == "allreduce":
        dist.all_reduce(tensor, op=dist.ReduceOp.SUM)
        out = tensor
    elif op == "broadcast":
        dist.broadcast(tensor, src=0)
        out = tensor
    elif op == "allgather":
        gathered = [torch.zeros_like(tensor) for _ in range(world_size)]
        dist.all_gather(gathered, tensor)
        out = torch.cat(gathered)
    elif op == "reduce_scatter":
        chunks = [c.contiguous() for c in tensor.chunk(world_size)]
        recv = torch.zeros_like(chunks[0])
        dist.reduce_scatter(recv, chunks, op=dist.ReduceOp.SUM)
        out = recv
    else:
        raise ValueError(f"unknown op {op}")
    out_queue.put((rank, out.clone()))
    out_queue.close()
    out_queue.join_thread()
    os._exit(0)


def gloo_reference(op: str, world_size: int,
                   per_rank_tensors: list) -> list:
    """Run the same operation through torch.distributed gloo for verification.

    Uses file-based init (file:// URI) because TCP init through libuv has
    known issues on macOS with concurrent process group creation.
    """
    ctx = mp.get_context("spawn")
    out_queue = ctx.Queue()
    init_dir = tempfile.mkdtemp(prefix="aie_gloo_")
    init_file = os.path.join(init_dir, "rendezvous")
    iface = _loopback_iface()

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/76-collective-ops-from-scratch/code/main.py:229 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rohitg00/ai-engineering-from-scratch@39ea8a1c6d (2026-08-26). Data as JSON: /api/errors/43d47f138470ae06. Report an issue: GitHub.