我一直在使用matplotlib函数plt.hist从值mV数组生成直方图数据。这在过去运作良好，但自从我更新了我的anaconda版本后，它又抛回了ValueError：
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/users/benjatin/HomeData/Code/buildSkyMap.py in <module>()
72 #get histogram of efficiencies
73 plt.figure()
---> 74 a=plt.hist(mV,bins=50)
75 plt.close()
76
/opt/apps/lsst/feb14/Linux64/anaconda/2.1.0/lib/python2.7/site-packages/matplotlib/pyplot.pyc in hist(x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, hold, **kwargs)
2888 histtype=histtype, align=align, orientation=orientation,
2889 rwidth=rwidth, log=log, color=color, label=label,
-> 2890 stacked=stacked, **kwargs)
2891 draw_if_interactive()
2892 finally:
/opt/apps/lsst/feb14/Linux64/anaconda/2.1.0/lib/python2.7/site-packages/matplotlib/axes/_axes.pyc in hist(self, x, bins, range, normed, weights, cumulative, bottom, histtype, align, orientation, rwidth, log, color, label, stacked, **kwargs)
5634 # this will automatically overwrite bins,
5635 # so that each histogram uses the same bins
-> 5636 m, bins = np.histogram(x[i], bins, weights=w[i], **hist_kwargs)
5637 m = m.astype(float) # causes problems later if it's an int
5638 if mlast is None:
/opt/apps/lsst/feb14/Linux64/anaconda/2.1.0/lib/python2.7/site-packages/numpy/lib/function_base.pyc in histogram(a, bins, range, normed, weights, density)
598 n.imag += np.bincount(indices, weights=tmp_w.imag, minlength=bins)
599 else:
--> 600 n += np.bincount(indices, weights=tmp_w, minlength=bins).astype(ntype)
601
602 # We now compute the bin edges since these are returned
ValueError: The first argument of bincount must be non-negative
mV中的所有值都不是负值，问题here也是如此：
In [34]: mV[mV < 0]
Out[34]: array([], dtype=float64)
我做的更新是：
conda: 3.7.0-py27_0 --> 4.0.5-py27_0 (soft-link)
openssl: 1.0.1h-1 --> 1.0.2h-0 (soft-link)
python: 2.7.8-1 --> 2.7.11-0 (soft-link)
pyyaml: 3.11-py27_0 --> 3.11-py27_1 (soft-link)
requests: 2.4.1-py27_0 --> 2.9.1-py27_0 (soft-link)
sqlite: 3.8.4.1-0 --> 3.9.2-0 (soft-link)
tk: 8.5.15-0 --> 8.5.18-0 (soft-link)
yaml: 0.1.4-0 --> 0.1.6-0 (soft-link)
zlib: 1.2.7-0 --> 1.2.8-0 (soft-link)
提前感谢您解决此问题的任何帮助。