Function isnan

imperative/python/megengine/functional/math.py:57–87

r"""Element-wise ``NaN`` check. Tests each element :math:`x_i` of the input tensor :math:`x` to determine whether the element is ``NaN``. Args: inp: input tensor. Should have a numeric data type. Returns: a tensor containing test results. An element out is

(inp: Tensor)

def isnan(inp: Tensor) -> Tensor:
    r"""Element-wise ``NaN`` check.
    
    Tests each element :math:`x_i` of the input tensor :math:`x` to determine whether the element is ``NaN``.

    Args:
        inp: input tensor. Should have a numeric data type.

    Returns:
        a tensor containing test results.
        An element out is ``True`` if :math:`x_i` is ``NaN`` and ``False`` otherwise.
        The returned array should have a data type of bool.

    Examples:
        
        >>> F.isnan(Tensor(1))
        Tensor(False, dtype=bool, device=xpux:0)

        .. TODO: Remove these comments when _elemwise_multi_type support scalar input
        .. >>> F.isnan(Tensor(float("nan")))
        .. Tensor(True, dtype=bool, device=xpux:0)

        Element-wise isnan:

        >>> x = Tensor([1, float("nan"), 0])
        >>> F.isnan(x)
        Tensor([False  True False], dtype=bool, device=xpux:0)
    """
    if not np.issubdtype(inp.dtype, np.floating):
        return broadcast_to(Const(False, np.bool_, inp.device), inp.shape)
    return _elemwise_multi_type(inp, mode="isnan", dtype="bool")


def isinf(inp: Tensor) -> Tensor: