comms.py 文件源码

def ber(x, y, m=2):
    """Measure bit error rate between symbols in x and y.

    :param x: symbol array #1
    :param y: symbol array #2
    :param m: symbol alphabet size (maximum 64)
    :returns: bit error rate

    >>> import arlpy
    >>> arlpy.comms.ber([0,1,2,3], [0,1,2,2], m=4)
    0.125
    """
    x = _np.asarray(x, dtype=_np.int)
    y = _np.asarray(y, dtype=_np.int)
    if _np.any(x >= m) or _np.any(y >= m) or _np.any(x < 0) or _np.any(y < 0):
        raise ValueError('Invalid data for specified m')
    if m == 2:
        return ser(x, y)
    if m > _MAX_M:
        raise ValueError('m > %d not supported' % (_MAX_M))
    n = _np.product(_np.shape(x))*_np.log2(m)
    e = x^y
    e = e[_np.nonzero(e)]
    e = _np.sum(_popcount[e])
    return float(e)/n