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Fonction i0 - module numpy.matlib

Signature de la fonction i0

def i0(x) 

Description

i0.__doc__

    Modified Bessel function of the first kind, order 0.

    Usually denoted :math:`I_0`.

    Parameters
    ----------
    x : array_like of float
        Argument of the Bessel function.

    Returns
    -------
    out : ndarray, shape = x.shape, dtype = float
        The modified Bessel function evaluated at each of the elements of `x`.

    See Also
    --------
    scipy.special.i0, scipy.special.iv, scipy.special.ive

    Notes
    -----
    The scipy implementation is recommended over this function: it is a
    proper ufunc written in C, and more than an order of magnitude faster.

    We use the algorithm published by Clenshaw [1]_ and referenced by
    Abramowitz and Stegun [2]_, for which the function domain is
    partitioned into the two intervals [0,8] and (8,inf), and Chebyshev
    polynomial expansions are employed in each interval. Relative error on
    the domain [0,30] using IEEE arithmetic is documented [3]_ as having a
    peak of 5.8e-16 with an rms of 1.4e-16 (n = 30000).

    References
    ----------
    .. [1] C. W. Clenshaw, "Chebyshev series for mathematical functions", in
           *National Physical Laboratory Mathematical Tables*, vol. 5, London:
           Her Majesty's Stationery Office, 1962.
    .. [2] M. Abramowitz and I. A. Stegun, *Handbook of Mathematical
           Functions*, 10th printing, New York: Dover, 1964, pp. 379.
           http://www.math.sfu.ca/~cbm/aands/page_379.htm
    .. [3] https://metacpan.org/pod/distribution/Math-Cephes/lib/Math/Cephes.pod#i0:-Modified-Bessel-function-of-order-zero

    Examples
    --------
    >>> np.i0(0.)
    array(1.0)
    >>> np.i0([0, 1, 2, 3])
    array([1.        , 1.26606588, 2.2795853 , 4.88079259])