小编JWi*_*Wil的帖子

我正在尝试将起点添加到流线图中。我在这里找到了一个使用起点的示例代码；在此链接中讨论了一个不同的问题，但 start_points 参数有效。我从这里获取了流线型示例代码（images_contours_and_fields 示例代码：streamplot_demo_features.py）。我不明白为什么我可以在一个代码中而不是另一个中定义起点。当我尝试在示例代码 (streamplot_demo_features.py) 中定义起点时，出现以下错误：

    Traceback (most recent call last):

  File "<ipython-input-79-981cad64cff6>", line 1, in <module>
    runfile('C:/Users/Admin/.spyder/StreamlineExample.py', wdir='C:/Users/Admin/.spyder')

  File "C:\ProgramData\Anaconda2\lib\site-packages\spyder\utils\site\sitecustomize.py", line 866, in runfile
    execfile(filename, namespace)

  File "C:\ProgramData\Anaconda2\lib\site-packages\spyder\utils\site\sitecustomize.py", line 87, in execfile
    exec(compile(scripttext, filename, 'exec'), glob, loc)

  File "C:/Users/Admin/.spyder/StreamlineExample.py", line 28, in <module>
    ax1.streamplot(X, Y, U, V,start_points=start_points)

  File "C:\ProgramData\Anaconda2\lib\site-packages\matplotlib\__init__.py", line 1891, in inner
    return func(ax, *args, **kwargs)

  File "C:\ProgramData\Anaconda2\lib\site-packages\matplotlib\axes\_axes.py", line 4620, in streamplot
    zorder=zorder)

  File "C:\ProgramData\Anaconda2\lib\site-packages\matplotlib\streamplot.py", line 144, in streamplot
    sp2[:, 0] += np.abs(x[0])

ValueError: …