generic.py 文件源码

def inv_mulaw(y, mu=256):
    """Inverse of mu-law companding (mu-law expansion)

    .. math::

        f^{-1}(x) = sign(y) (1 / \mu) (1 + \mu)^{|y|} - 1)

    Args:
        y (array-like): Compressed signal. Each value of input signal must be in
          range of [-1, 1].
        mu (number): Compression parameter ``?``.

    Returns:
        array-like: Uncomprresed signal (-1 <= x <= 1)

    See also:
        :func:`nnmnkwii.preprocessing.inv_mulaw`
        :func:`nnmnkwii.preprocessing.mulaw_quantize`
        :func:`nnmnkwii.preprocessing.inv_mulaw_quantize`
    """
    return _sign(y) * (1.0 / mu) * ((1.0 + mu)**_abs(y) - 1.0)