def tip_zscores(a):
    """
    Calculates the "target identification from profiles" (TIP) zscores
    from Cheng et al. 2001, Bioinformatics 27(23):3221-3227.

    :param a: NumPy array, where each row is the signal for a feature.
    """
    weighted = a * a.mean(axis=0)
    scores = weighted.sum(axis=1)
    zscores = (scores - scores.mean()) / scores.std()
    return zscores