keras-team/keras · error · ValueError

If imagenet weights are being loaded, alpha can be one of`0.

Error message

If imagenet weights are being loaded, alpha can be one of`0.25`, `0.50`, `0.75` or `1.0` only.  Received alpha={alpha}

What it means

Error "If imagenet weights are being loaded, alpha can be one of`0.25`, `0.50`, `0.75` or `1.0` only. Received alpha={alpha}" thrown in keras-team/keras.

Source

Thrown at keras/src/applications/mobilenet.py:167

    )

    if backend.image_data_format() == "channels_last":
        row_axis, col_axis = (0, 1)
    else:
        row_axis, col_axis = (1, 2)
    rows = input_shape[row_axis]
    cols = input_shape[col_axis]

    if weights == "imagenet":
        if depth_multiplier != 1:
            raise ValueError(
                "If imagenet weights are being loaded, "
                "depth multiplier must be 1.  "
                f"Received depth_multiplier={depth_multiplier}"
            )

        if alpha not in [0.25, 0.50, 0.75, 1.0]:
            raise ValueError(
                "If imagenet weights are being loaded, "
                "alpha can be one of"
                "`0.25`, `0.50`, `0.75` or `1.0` only.  "
                f"Received alpha={alpha}"
            )

        if rows != cols or rows not in [128, 160, 192, 224]:
            rows = 224
            warnings.warn(
                "`input_shape` is undefined or non-square, "
                "or `rows` is not in [128, 160, 192, 224]. "
                "Weights for input shape (224, 224) will be "
                "loaded as the default.",
                stacklevel=2,
            )

    if input_tensor is None:
        img_input = layers.Input(shape=input_shape)

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/applications/mobilenet.py:167 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/c506c230b7080c5c. Report an issue: GitHub.