keras-team/keras · error · ValueError

Cannot perform batch_dot over axis 0. If your inputs are not

Error message

Cannot perform batch_dot over axis 0. If your inputs are not batched, add a dummy batch dimension to your inputs using keras.ops.expand_dims(x, 0)

What it means

Error "Cannot perform batch_dot over axis 0. If your inputs are not batched, add a dummy batch dimension to your inputs using keras.ops.expand_dims(x, 0)" thrown in keras-team/keras.

Source

Thrown at keras/src/layers/merging/dot.py:105

    if any(isinstance(a, (list, tuple)) for a in axes):
        raise ValueError(
            f"Multiple target dimensions are not supported. "
            f"Expected: None, int, (int, int), "
            f"Provided: {axes} "
        )

    # if tuple, convert to list.
    axes = list(axes)

    # convert negative indices.
    if axes[0] < 0:
        axes[0] += x_ndim
    if axes[1] < 0:
        axes[1] += y_ndim

    # sanity checks
    if 0 in axes:
        raise ValueError(
            "Cannot perform batch_dot over axis 0. "
            "If your inputs are not batched, "
            "add a dummy batch dimension to your "
            "inputs using keras.ops.expand_dims(x, 0)"
        )
    a0, a1 = axes
    d1 = x_shape[a0]
    d2 = y_shape[a1]

    if d1 is not None and d2 is not None and d1 != d2:
        raise ValueError(
            f"Cannot do batch_dot on inputs with shapes "
            f"{x_shape} and {y_shape} with axes={axes}. "
            f"x.shape[{axes[0]}] != y.shape[{axes[1]}] ({d1} != {d2})."
        )

    # backup ndims. Need them later.
    orig_x_ndim = x_ndim

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/layers/merging/dot.py:105 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/384363e0fb5aeb01. Report an issue: GitHub.