Hi! Bumping this upstream from Sage, where we use quiver to draw
slope fields. The following code
###
import matplotlib.pyplot as plt
import numpy as np
fig = plt.figure()
r = np.arange(10)
X,Y = np.meshgrid(r,r)
U, V = np.cos(X), np.sin(Y)
Q = plt.quiver( U, V, headlength=0, headaxislength=0)
###
produces exactly what we want, but generates some warnings:
/usr/local/lib/python2.7/dist-packages/matplotlib/quiver.py:622:
RuntimeWarning: divide by zero encountered in divide
shrink = length/minsh
/usr/local/lib/python2.7/dist-packages/matplotlib/quiver.py:623:
RuntimeWarning: invalid value encountered in multiply
X0 = shrink * X0[np.newaxis,:]
/usr/local/lib/python2.7/dist-packages/matplotlib/quiver.py:624:
RuntimeWarning: invalid value encountered in multiply
Y0 = shrink * Y0[np.newaxis,:]
We can get around this by using some tiny headlength (minsh =
self.minshaft * self.headlength) but it seems more natural to avoid
drawing one entirely. Would there be any objections to a pull request
which special-cased 0 to avoid this?
Doug
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