Module « numpy.random »

Classe « MT19937 »

Informations générales

Héritage

builtins.object
    BitGenerator
        MT19937

Définition

class MT19937(BitGenerator):

Description _{[extrait de MT19937.__doc__]}

    MT19937(seed=None)

    Container for the Mersenne Twister pseudo-random number generator.

    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.

    Attributes
    ----------
    lock: threading.Lock
        Lock instance that is shared so that the same bit git generator can
        be used in multiple Generators without corrupting the state. Code that
        generates values from a bit generator should hold the bit generator's
        lock.

    Notes
    -----
    ``MT19937`` provides a capsule containing function pointers that produce
    doubles, and unsigned 32 and 64- bit integers [1]_. These are not
    directly consumable in Python and must be consumed by a ``Generator``
    or similar object that supports low-level access.

    The Python stdlib module "random" also contains a Mersenne Twister
    pseudo-random number generator.

    **State and Seeding**

    The ``MT19937`` state vector consists of a 624-element array of
    32-bit unsigned integers plus a single integer value between 0 and 624
    that indexes the current position within the main array.

    The input seed is processed by `SeedSequence` to fill the whole state. The
    first element is reset such that only its most significant bit is set.

    **Parallel Features**

    The preferred way to use a BitGenerator in parallel applications is to use
    the `SeedSequence.spawn` method to obtain entropy values, and to use these
    to generate new BitGenerators:

    >>> from numpy.random import Generator, MT19937, SeedSequence
    >>> sg = SeedSequence(1234)
    >>> rg = [Generator(MT19937(s)) for s in sg.spawn(10)]

    Another method is to use `MT19937.jumped` which advances the state as-if
    :math:`2^{128}` random numbers have been generated ([1]_, [2]_). This
    allows the original sequence to be split so that distinct segments can be
    used in each worker process. All generators should be chained to ensure
    that the segments come from the same sequence.

    >>> from numpy.random import Generator, MT19937, SeedSequence
    >>> sg = SeedSequence(1234)
    >>> bit_generator = MT19937(sg)
    >>> rg = []
    >>> for _ in range(10):
    ...    rg.append(Generator(bit_generator))
    ...    # Chain the BitGenerators
    ...    bit_generator = bit_generator.jumped()

    **Compatibility Guarantee**

    ``MT19937`` makes a guarantee that a fixed seed and will always produce
    the same random integer stream.

    References
    ----------
    .. [1] Hiroshi Haramoto, Makoto Matsumoto, and Pierre L'Ecuyer, "A Fast
        Jump Ahead Algorithm for Linear Recurrences in a Polynomial Space",
        Sequences and Their Applications - SETA, 290--298, 2008.
    .. [2] Hiroshi Haramoto, Makoto Matsumoto, Takuji Nishimura, François
        Panneton, Pierre L'Ecuyer, "Efficient Jump Ahead for F2-Linear
        Random Number Generators", INFORMS JOURNAL ON COMPUTING, Vol. 20,
        No. 3, Summer 2008, pp. 385-390.

    

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__