python - 带箭头的 matplotlib 3d 线图无法接受 kwargs

Question

为什么会产生错误？ ax.quiver 中的 kwarg 枢轴会导致代码失败，但没有 kwarg 也能正常工作。错误消息也不是很有帮助。我正在使用 Python 3.4 和 matplotlib 1.4.3。谢谢。

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
fig = plt.figure()

ax = plt.axes(projection='3d')

x=[0,0,4,4]
y=[0,5,5,5]
z=[0,0,0,-2]

ax.plot(x, y, z, '-b', linewidth=5)
ax.view_init(30, 30)

ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')

X=[0]
Y=[5]
Z=[0]
U=[-60]
V=[40]
W=[20]

ax.quiver3D(X, Y, Z, U, V, W, pivot='tail')

错误信息

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-37-f68d70030cee> in <module>()
     25 #ax.quiver3D(X, Y, Z, U, V, W)
     26 
---> 27 ax.quiver3D(X, Y, Z, U, V, W, pivot='tail')

C:\Users\neal\Anaconda3\lib\site-packages\mpl_toolkits\mplot3d\axes3d.py in quiver(self, *args, **kwargs)
   2615             lines.append(line)
   2616 
-> 2617         linec = art3d.Line3DCollection(lines, *args[argi:], **kwargs)
   2618         self.add_collection(linec)
   2619 

C:\Users\neal\Anaconda3\lib\site-packages\mpl_toolkits\mplot3d\art3d.py in __init__(self, segments, *args, **kwargs)
    169         Keyword arguments are passed onto :func:`~matplotlib.collections.LineCollection`.
    170         '''
--> 171         LineCollection.__init__(self, segments, *args, **kwargs)
    172 
    173     def set_sort_zpos(self,val):

C:\Users\neal\Anaconda3\lib\site-packages\matplotlib\collections.py in __init__(self, segments, linewidths, colors, antialiaseds, linestyles, offsets, transOffset, norm, cmap, pickradius, zorder, **kwargs)
   1081             pickradius=pickradius,
   1082             zorder=zorder,
-> 1083             **kwargs)
   1084 
   1085         self.set_segments(segments)

C:\Users\neal\Anaconda3\lib\site-packages\matplotlib\collections.py in __init__(self, edgecolors, facecolors, linewidths, linestyles, antialiaseds, offsets, transOffset, norm, cmap, pickradius, hatch, urls, offset_position, zorder, **kwargs)
    133 
    134         self._path_effects = None
--> 135         self.update(kwargs)
    136         self._paths = None
    137 

C:\Users\neal\Anaconda3\lib\site-packages\matplotlib\artist.py in update(self, props)
    755             func = getattr(self, 'set_' + k, None)
    756             if func is None or not six.callable(func):
--> 757                 raise AttributeError('Unknown property %s' % k)
    758             func(v)
    759             changed = True

AttributeError: Unknown property pivot

Answer 1

您需要更新 matplotlib。

来自documentation of version 1.5.0 (第 641 页):

quiver3D(*args, **kwargs)

Plot a 3D field of arrows.

...

Keyword arguments:

length: [1.0 | float] The length of each quiver, default to 1.0, the unit is the same with the axes

arrow_length_ratio: [0.3 | float] The ratio of the arrow head with respect to the quiver, default to 0.3

pivot: [ ‘tail’ | ‘middle’ | ‘tip’ ] The part of the arrow that is at the grid point; the arrow rotates about this point, hence the name pivot.

Any additional keyword arguments are delegated to LineCollection

与 documentation of version 1.4.3 相同(第 567 页):

quiver3D(*args, **kwargs)

Plot a 3D field of arrows.

...

Keyword arguments:

length: [1.0 | float] The length of each quiver, default to 1.0, the unit is the same with the axes

arrow_length_ratio: [0.3 | float] The ratio of the arrow head with respect to the quiver, default to 0.3

Any additional keyword arguments are delegated to LineCollection

该功能在 1.4.3 中完全缺失，这也解释了为什么没有信息丰富的错误消息:pivot 关键字被传递给 LineCollection，这可以没有任何意义。