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

window_size must be greater than 1

Error message

window_size must be greater than 1

What it means

Error "window_size must be greater than 1" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/43-hdf5-tokenized-corpus/code/main.py:344

        if cursor != stop - start:
            raise RuntimeError(
                f"slice read produced {cursor} tokens, expected {stop - start}"
            )
        return out


class SlidingWindowDataloader:
    """Random sliding-window sampler over a flat token stream."""

    def __init__(
        self,
        store: MmapTokenStore,
        window_size: int = DEFAULT_WINDOW_SIZE,
        batch_size: int = 4,
        seed: int = 0,
    ) -> None:
        if window_size <= 1:
            raise ValueError("window_size must be greater than 1")
        if batch_size <= 0:
            raise ValueError("batch_size must be positive")
        if store.total_tokens <= window_size:
            raise ValueError(
                f"store has only {store.total_tokens} tokens; need more than {window_size}"
            )
        self.store = store
        self.window_size = window_size
        self.batch_size = batch_size
        self._random = random.Random(seed)
        self._max_start = store.total_tokens - window_size - 1

    def _sample_window(self) -> tuple[np.ndarray, np.ndarray]:
        start = self._random.randint(0, self._max_start)
        chunk = self.store.get_slice(start, start + self.window_size + 1)
        return chunk[:-1], chunk[1:]

    def __iter__(self) -> Iterator[tuple[np.ndarray, np.ndarray]]:

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/43-hdf5-tokenized-corpus/code/main.py:344 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/ec61e23ec27fac66. Report an issue: GitHub.