window.py 文件源码

def hanning(M):
    """Returns the Hanning window.

    The Hanning window is defined as

    .. math::
        w(n) = 0.5 - 0.5\\cos\\left(\\frac{2\\pi{n}}{M-1}\\right)
        \\qquad 0 \\leq n \\leq M-1

    Args:
        M (:class:`~int`):
            Number of points in the output window. If zero or less, an empty
            array is returned.

    Returns:
        ~cupy.ndarray: Output ndarray.

    .. seealso:: :func:`numpy.hanning`
    """
    if M < 1:
        return from_data.array([])
    if M == 1:
        return basic.ones(1, float)
    n = ranges.arange(0, M)
    return 0.5 - 0.5 * trigonometric.cos(2.0 * numpy.pi * n / (M - 1))