[Numpy-discussion] trivial question?

2012-06-20 Thread Neal Becker 
Maybe I'm being slow, but is there any convenient function to calculate,
for 2 vectors:

\sum_i \sum_j x_i y_j

(I had a matrix once, but it vanished without a trace)

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Re: [Numpy-discussion] trivial question?

2012-06-20 Thread Robert Kern 
On Wed, Jun 20, 2012 at 3:58 PM, Neal Becker ndbeck...@gmail.com wrote:
 Maybe I'm being slow, but is there any convenient function to calculate,
 for 2 vectors:

 \sum_i \sum_j x_i y_j

 (I had a matrix once, but it vanished without a trace)

np.multiply.outer(x, y).sum()

-- 
Robert Kern
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Re: [Numpy-discussion] trivial question?

2012-06-20 Thread Charles R Harris 
On Wed, Jun 20, 2012 at 8:58 AM, Neal Becker ndbeck...@gmail.com wrote:

 Maybe I'm being slow, but is there any convenient function to calculate,
 for 2 vectors:

 \sum_i \sum_j x_i y_j


It factors, just do x.sum()*y.sum().

Chuck
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