keras-team/keras · error · ValueError

The mask provided should be one dimension less than the inpu

Error message

The mask provided should be one dimension less than the inputs. Received: mask.shape={mask.shape}, inputs.shape={inputs.shape}

What it means

Error "The mask provided should be one dimension less than the inputs. Received: mask.shape={mask.shape}, inputs.shape={inputs.shape}" thrown in keras-team/keras.

Source

Thrown at keras/src/layers/normalization/batch_normalization.py:339

            axes = [self.axis]
        else:
            axes = self.axis

        for axis in axes:
            if axis >= len(input_shape) or axis < -len(input_shape):
                raise ValueError(
                    f"Axis {axis} is out of bounds for "
                    f"input shape {input_shape}. "
                    f"Received: axis={self.axis}"
                )
        return input_shape

    def call(self, inputs, training=None, mask=None):
        # Check if the mask has one less dimension than the inputs.
        if mask is not None:
            if len(mask.shape) != len(inputs.shape) - 1:
                # Raise a value error
                raise ValueError(
                    "The mask provided should be one dimension less "
                    "than the inputs. Received: "
                    f"mask.shape={mask.shape}, inputs.shape={inputs.shape}"
                )

        compute_dtype = backend.result_type(inputs.dtype, "float32")
        # BN is prone to overflow with float16/bfloat16 inputs, so we upcast to
        # float32 for the subsequent computations.
        inputs = ops.cast(inputs, compute_dtype)

        moving_mean = ops.cast(self.moving_mean, inputs.dtype)
        moving_variance = ops.cast(self.moving_variance, inputs.dtype)

        if self.scale:
            gamma = ops.cast(self.gamma, inputs.dtype)
        else:
            gamma = None

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/layers/normalization/batch_normalization.py:339 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/82fba81ccff195a1. Report an issue: GitHub.