my bug of VG algorithm

def visibility_graph(series):
    g = nx.Graph()

    # convert list of magnitudes into list of tuples that hold the index
    tseries = []
    n = 0
    for magnitude in series:
        tseries.append((n, magnitude))
        n += 1

    '''add nodes'''
    for i in range(len(tseries)):
        (ta, ya) = tseries[i]
        g.add_node(ta, mag=ya)

    '''add edges'''
    for a, b in combinations(tseries, 2):
        (ta, ya) = a
        (tb, yb) = b
        connect = True
        if tb - ta > 1:
            (tc, yc) = max(tseries[ta + 1:tb])  #我的算法
            print(tc,yc)
            if (yc > yb + (ya - yb) * ((tb - tc) / (tb - ta))):
                connect = False

        # medium = tseries[ta+1 :tb]  #别人的算法
        # for tc, yc in medium:
        #     if yc > yb + (ya - yb) * ((tb - tc) / (tb - ta)):
        #         connect = False

        if connect:
            g.add_edge(ta, tb)

    return g

在第22行中,由于tseires 变成了嵌入元组, 所以max(tseries[ta + 1:tb]) 会取下标最大的值, 而非最大的第二个元素.

[(0, 0.19024852355156963),
(1, 0.6660417262541884),
(2, 0.395523497583831),
(3, 0.19024852355156963)]