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

safetensors file not found: {path}

Error message

safetensors file not found: {path}

What it means

Error "safetensors file not found: {path}" thrown in rohitg00/ai-engineering-from-scratch.

Source

Thrown at phases/19-capstone-projects/37-loading-pretrained-weights/code/main.py:215

        mapping[f"{prefix_src}.attn.c_attn.weight"] = f"{prefix_dst}.attn.qkv.weight"
        mapping[f"{prefix_src}.attn.c_attn.bias"] = f"{prefix_dst}.attn.qkv.bias"
        mapping[f"{prefix_src}.attn.c_proj.weight"] = f"{prefix_dst}.attn.out_proj.weight"
        mapping[f"{prefix_src}.attn.c_proj.bias"] = f"{prefix_dst}.attn.out_proj.bias"
        mapping[f"{prefix_src}.mlp.c_fc.weight"] = f"{prefix_dst}.mlp.fc1.weight"
        mapping[f"{prefix_src}.mlp.c_fc.bias"] = f"{prefix_dst}.mlp.fc1.bias"
        mapping[f"{prefix_src}.mlp.c_proj.weight"] = f"{prefix_dst}.mlp.fc2.weight"
        mapping[f"{prefix_src}.mlp.c_proj.bias"] = f"{prefix_dst}.mlp.fc2.bias"
    return mapping


def _needs_transpose(pretrained_name: str) -> bool:
    return any(pretrained_name.endswith(suffix) for suffix in CONV1D_SUFFIXES)


def load_safetensors(model: GPTModel, path: Path, verbose: bool = True) -> LoadReport:
    """Load weights into model. Refuse to assign on shape mismatch. Returns a report."""
    if not path.exists():
        raise FileNotFoundError(f"safetensors file not found: {path}")

    mapping = make_pretrained_to_local(model.cfg.num_layers)
    local_params = dict(model.named_parameters())
    report = LoadReport()

    seen_local: set[str] = set()
    pending: list[tuple[str, str, torch.Tensor]] = []
    with safe_open(str(path), framework="pt") as reader:
        pretrained_names = list(reader.keys())
        for src_name in pretrained_names:
            local_name = mapping.get(src_name)
            if local_name is None:
                report.unexpected.append(src_name)
                if verbose:
                    print(f"  [skip] {src_name} (no mapping)")
                continue
            if local_name not in local_params:
                report.unexpected.append(src_name)

View on GitHub (pinned to 39ea8a1c6d)

When it happens

Trigger: Thrown at phases/19-capstone-projects/37-loading-pretrained-weights/code/main.py:215 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/2bf798838826f1e2. Report an issue: GitHub.