keras-team/keras · error · ValueError

`sparse=True` is not supported with numpy backend

Error message

`sparse=True` is not supported with numpy backend

What it means

Error "`sparse=True` is not supported with numpy backend" thrown in keras-team/keras.

Source

Thrown at keras/src/backend/numpy/core.py:40

class Variable(KerasVariable):
    def _initialize(self, value):
        self._value = value

    def _direct_assign(self, value):
        self._value = np.array(value, dtype=self._dtype)

    def _convert_to_tensor(self, value, dtype=None):
        return convert_to_tensor(value, dtype=dtype)

    # Overload native accessor.
    def __array__(self):
        return self.value


def convert_to_tensor(x, dtype=None, sparse=None, ragged=None):
    if sparse:
        raise ValueError("`sparse=True` is not supported with numpy backend")
    if ragged:
        raise ValueError("`ragged=True` is not supported with numpy backend")
    if dtype is not None:
        dtype = standardize_dtype(dtype)
    if isinstance(x, Variable):
        if dtype and dtype != x.dtype:
            return x.value.astype(dtype)
        return x.value
    if not is_tensor(x) and standardize_dtype(dtype) == "bfloat16":
        # Can't create bfloat16 arrays on the fly (e.g. from a h5 Dataset).
        # Instead we convert "as is" (to stored dtype) and cast.
        return np.asarray(x).astype(dtype)
    if dtype is None:
        dtype = result_type(
            *[getattr(item, "dtype", type(item)) for item in tree.flatten(x)]
        )
    return np.array(x, dtype=dtype)

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/backend/numpy/core.py:40 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/e2cf59fad0030f3f. Report an issue: GitHub.