On 5/4/2011 10:30 AM, Patrick P. wrote:
Hello,
I hope this is the right way to ask my question, if not, sorry to bother
you. Maybe you can tell me who to ask.
Ok so here is my code
[snip]
A = np.array([[m111,m121], [m211,m221]])
B = np.array([[m112,m122], [m212,m222]])
print(np.dot(A,B))
Traceback (most recent call last):
File "C:/Python26/helpfiletest.py", line 36, in <module>
print(np.dot(A,B))
ValueError: objects are not aligned
-------------------------------------------------------------------------------------
I get it why theres and error message, because it's trying to multiply a
2x2x100 array with another 2x2x100 array and doesn't know how to do that.
What I actually want is 100 2x2 arrays and then mutliply them individually.
Can anyone help me with that?
As Alan said, you'll likely get good help on the numpy listserv, but I
think this might be what you want, although I'm not sure it's the
tersest way to express it:
# Swap axes twice on A and B to make them (100, 2, 2)
A_new = np.swapaxes(np.swapaxes(A, 0, 2), 1, 2)
B_new = np.swapaxes(np.swapaxes(B, 0, 2), 1, 2)
# Multiply the 2x2 arrays together using list comprehension
C = np.array([np.dot(a, b) for a, b in zip(A_new, B_new)])
print C
I'm certain there is a more clever way (ie. some function within numpy)
to do that last part.
matt
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