def lim_eps(a, eps):
#==================================================================
    """
    Return min / max of an array a, increased by eps*(max(a) - min(a)). 
    Handy for nice looking axes labeling.
    """
    mylim = (min(a) - (max(a)-min(a))*eps, max(a) + (max(a)-min(a))*eps)
    return mylim