[Numpy-discussion] Matrix and var method
Zachary Pincus
zpincus at stanford.edu
Sat Apr 22 20:48:00 EDT 2006
Hi folks,
I just ran across an error with numpy.matrix types: the var() method
does not seem to work! (I've tried all sorts of permutations on the
matrix shape, and the axis parameter to var; nothing works.)
Perhaps this has already been fixed -- I haven't updated my numpy in
a week or so. If so, sorry; if not, I hope this helps.
Zach
In [1]: import numpy
In [2]: numpy.__version__
Out[2]: '0.9.7.2335'
In [3]: numpy.matrix([[1,2,3], [1,2,3]]).var()
------------------------------------------------------------------------
---
exceptions.ValueError Traceback (most
recent call last)
/Users/zpincus/<ipython console>
/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-
packages/numpy/core/defmatrix.py in __mul__(self, other)
147 if isinstance(other, N.ndarray) or N.isscalar(other)
or \
148 not hasattr(other, '__rmul__'):
--> 149 return N.dot(self, other)
150 else:
151 return NotImplemented
ValueError: matrices are not aligned
In [4]: numpy.array([[1,2,3], [1,2,3]]).var()
Out[4]: 0.80000000000000004
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