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

temperature must be positive

Error message

temperature must be positive

What it means

Error "temperature must be positive" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/35-gpt-model-assembly/code/main.py:206

    threshold = values[..., -1:]
    return torch.where(logits < threshold, torch.full_like(logits, float("-inf")), logits)


def generate(
    model: GPTModel,
    prompt: torch.Tensor,
    max_new_tokens: int,
    temperature: float = 1.0,
    top_k: int | None = None,
    seed: int | None = None,
) -> torch.Tensor:
    """Autoregressive generation with multinomial sampling, temperature, top-k.

    Holds the active window to model.cfg.context_length by sliding the oldest
    tokens out when the running sequence overflows.
    """
    if temperature <= 0:
        raise ValueError("temperature must be positive")
    if seed is not None:
        torch.manual_seed(seed)

    was_training = model.training
    model.eval()
    tokens = prompt.clone()
    try:
        with torch.no_grad():
            for _ in range(max_new_tokens):
                window = tokens[:, -model.cfg.context_length:]
                logits = model(window)
                next_logits = logits[:, -1, :] / temperature
                next_logits = top_k_filter(next_logits, top_k)
                probs = F.softmax(next_logits, dim=-1)
                next_token = torch.multinomial(probs, num_samples=1)
                tokens = torch.cat([tokens, next_token], dim=1)
        return tokens
    finally:

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/35-gpt-model-assembly/code/main.py:206 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/ef3988b392873099. Report an issue: GitHub.