decimal.Decimal 'floor division' is integer division that truncates toward 0 (see 9.4.2).

    >>> Decimal('-0.5').__floor__()
    -1
    >>> Decimal('-0.5').__floordiv__(1)
   Decimal('-0')

Numpy 1.8.1:

    >>> np.float32(-0.5) // 1
    -1.0
    >>> np.float32(-0.5) // float('inf')
    -0.0

    >>> np.array([-0.5]) // 1
    array([-1.])
    >>> np.array([-0.5]) // float('inf')
    array([-0.])