Comfy-Org/ComfyUI · error · ValueError

Unknown reference view selection strategy: {strategy!r}. Mus

Error message

Unknown reference view selection strategy: {strategy!r}. Must be one of: 'first', 'middle', 'saddle_balanced', 'saddle_sim_range'

What it means

The DA3 reference-view selector picks a reference frame by strategy name: 'first', 'middle', 'saddle_balanced', or 'saddle_sim_range'. Any other string falls through to a ValueError listing the valid options. The strategy is a parameter of the selection routine, usually hardcoded or exposed by a node.

Source

Thrown at comfy/ldm/depth_anything_3/reference_view_selector.py:54

        feat_var = img_class_feat.var(dim=-1)                        # (B,S)

        def _normalize(metric):
            mn = metric.min(dim=1, keepdim=True).values
            mx = metric.max(dim=1, keepdim=True).values
            return (metric - mn) / (mx - mn + 1e-8)

        sim_n, norm_n, var_n = _normalize(sim_score), _normalize(feat_norm), _normalize(feat_var)
        balance = (sim_n - 0.5).abs() + (norm_n - 0.5).abs() + (var_n - 0.5).abs()
        return balance.argmin(dim=1)

    if strategy == "saddle_sim_range":
        sim = torch.matmul(img_class_feat, img_class_feat.transpose(1, 2))
        sim_no_diag = sim - torch.eye(S, device=sim.device).unsqueeze(0)
        sim_max = sim_no_diag.max(dim=-1).values
        sim_min = sim_no_diag.min(dim=-1).values
        return (sim_max - sim_min).argmax(dim=1)

    raise ValueError(
        f"Unknown reference view selection strategy: {strategy!r}. "
        f"Must be one of: 'first', 'middle', 'saddle_balanced', 'saddle_sim_range'"
    )


def reorder_by_reference(x: torch.Tensor, b_idx: torch.Tensor) -> torch.Tensor:
    """Reorder x so the reference view is at position 0 in axis S."""
    B, S = x.shape[0], x.shape[1]
    if S <= 1:
        return x
    positions = torch.arange(S, device=x.device).unsqueeze(0).expand(B, -1)
    b_idx_exp = b_idx.unsqueeze(1)
    reorder = torch.where(
        (positions > 0) & (positions <= b_idx_exp),
        positions - 1,
        positions,
    )
    reorder[:, 0] = b_idx

View on GitHub (pinned to 1c6d8d45b3)

Solutions

Use one of the four exact strings: 'first', 'middle', 'saddle_balanced', 'saddle_sim_range'.
If exposing in a node, use a fixed combo input constrained to the four values.
Add the missing strategy branch yourself if you truly need new behavior, before the final raise.

Example fix

# before
idx = select_reference_view(feat, strategy="saddle_balance")

# after
idx = select_reference_view(feat, strategy="saddle_balanced")

Defensive patterns

Strategy: type-guard

Validate before calling

STRATEGIES = {"first", "middle", "saddle_balanced", "saddle_sim_range"}
assert strategy in STRATEGIES, f"strategy must be one of {sorted(STRATEGIES)}"

Type guard

def is_valid_reference_strategy(strategy: str) -> bool:
    return strategy in {"first", "middle", "saddle_balanced", "saddle_sim_range"}

Prevention

Use a fixed allowlist for strategy strings at the node/UI boundary.
Copy strategy names from the raise message itself (it is the authoritative allowlist).

When it happens

Trigger: Calling select_reference_view (or its caller) with a strategy string that misses the allowlist — typo such as 'saddle_balance', or a new strategy name from a different repo revision.

Common situations: Custom nodes exposing the strategy as a text input; syncing code between upstream DA3 forks where strategy names diverged.

Related errors

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/b8753d44a5de421c. Report an issue: GitHub.