util.py 文件源码

def _log_single(x):
    """Sanitized log function for a single element.
    Since this method internally calls np.log and carries
    the (very likely) possibility to overflow, the method
    suppresses all warnings.

    #XXX: at some point we might want to let ``suppress_warnings``
    # specify exactly which types of warnings it should filter.

    Parameters
    ----------

    x : float, int
        The number to log

    Returns
    -------

    val : float
        the log of x
    """
    x = np.maximum(0, x)
    val = __min_log__ if x == 0 else np.maximum(__min_log__, np.log(x))
    return val