op_utils.py 文件源码

def vecnorm(vec, norm, epsilon=1e-3):
    """
    Scale a vector to unit length. The only exception is the zero vector, which
    is returned back unchanged.
    """
    if norm not in ('prob', 'max1', 'logmax1'):
        raise ValueError("'%s' is not a supported norm. Currently supported norms include 'prob',\
             'max1' and 'logmax1'." % norm)

    if isinstance(vec, np.ndarray):
        vec = np.asarray(vec, dtype=float)
        if norm == 'prob':
            veclen = np.sum(np.abs(vec)) + epsilon * len(vec) # smoothing
        elif norm == 'max1':
            veclen = np.max(vec) + epsilon
        elif norm == 'logmax1':
            vec = np.log10(1. + vec)
            veclen = np.max(vec) + epsilon
        if veclen > 0.0:
            return (vec + epsilon) / veclen
        else:
            return vec
    else:
        raise ValueError('vec should be ndarray, found: %s' % type(vec))