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

step log is empty

Error message

step log is empty

What it means

Error "step log is empty" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/44-cosine-lr-warmup/code/main.py:331

@dataclass
class StepLogSummary:
    """Reduction of a per-step log to the numbers a reviewer scans first."""

    steps: int
    lr_peak: float
    lr_final: float
    grad_l2_peak: float
    loss_initial: float
    loss_final: float
    loss_delta: float


def summarize_step_log(log: Iterable[StepLog]) -> StepLogSummary:
    rows = list(log)
    if not rows:
        raise ValueError("step log is empty")
    return StepLogSummary(
        steps=len(rows),
        lr_peak=max(row.lr for row in rows),
        lr_final=rows[-1].lr,
        grad_l2_peak=max(row.grad_l2_norm for row in rows),
        loss_initial=rows[0].loss,
        loss_final=rows[-1].loss,
        loss_delta=rows[-1].loss - rows[0].loss,
    )


def split_decay_groups(
    model: nn.Module,
    weight_decay: float = 0.01,
    no_decay_names: tuple[str, ...] = ("bias", "LayerNorm.weight", "layer_norm.weight"),
) -> list[dict[str, object]]:
    """Split model parameters into a decay and a no-decay group.

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/44-cosine-lr-warmup/code/main.py:331 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/f21caea96c0d8db9. Report an issue: GitHub.