Module « numpy.random »

Classe « SFC64 »

Informations générales

Héritage

builtins.object
    BitGenerator
        SFC64

Définition

class SFC64(BitGenerator):

Description _{[extrait de SFC64.__doc__]}

    SFC64(seed=None)

    BitGenerator for Chris Doty-Humphrey's Small Fast Chaotic PRNG.

    Parameters
    ----------
    seed : {None, int, array_like[ints], SeedSequence}, optional
        A seed to initialize the `BitGenerator`. If None, then fresh,
        unpredictable entropy will be pulled from the OS. If an ``int`` or
        ``array_like[ints]`` is passed, then it will be passed to
        `SeedSequence` to derive the initial `BitGenerator` state. One may also
        pass in a `SeedSequence` instance.

    Notes
    -----
    ``SFC64`` is a 256-bit implementation of Chris Doty-Humphrey's Small Fast
    Chaotic PRNG ([1]_). ``SFC64`` has a few different cycles that one might be
    on, depending on the seed; the expected period will be about
    :math:`2^{255}` ([2]_). ``SFC64`` incorporates a 64-bit counter which means
    that the absolute minimum cycle length is :math:`2^{64}` and that distinct
    seeds will not run into each other for at least :math:`2^{64}` iterations.

    ``SFC64`` provides a capsule containing function pointers that produce
    doubles, and unsigned 32 and 64- bit integers. These are not
    directly consumable in Python and must be consumed by a ``Generator``
    or similar object that supports low-level access.

    **State and Seeding**

    The ``SFC64`` state vector consists of 4 unsigned 64-bit values. The last
    is a 64-bit counter that increments by 1 each iteration.

    The input seed is processed by `SeedSequence` to generate the first
    3 values, then the ``SFC64`` algorithm is iterated a small number of times
    to mix.

    **Compatibility Guarantee**

    ``SFC64`` makes a guarantee that a fixed seed will always produce the same
    random integer stream.

    References
    ----------
    .. [1] `"PractRand"
            <http://pracrand.sourceforge.net/RNG_engines.txt>`_
    .. [2] `"Random Invertible Mapping Statistics"
            <http://www.pcg-random.org/posts/random-invertible-mapping-statistics.html>`_
    

Constructeur(s)

Signature du constructeur	Description
__new__(*args, **kwargs)	Create and return a new object. See help(type) for accurate signature. [extrait de __new__.__doc__]
__init__(self, /, *args, **kwargs)	Initialize self. See help(type(self)) for accurate signature. [extrait de __init__.__doc__]

Attributs statiques hérités de la classe BitGenerator

capsule, cffi, ctypes, lock

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe BitGenerator

__getstate__, __init_subclass__, __reduce__, __setstate__, __subclasshook__, random_raw

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __hash__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__