On Wed, Jun 27, 2012 at 2:38 PM, <x.pi...@gmail.com> wrote:
> How how can I perform matrix multiplication of two vectors?
> (in matlab I do it like a*a')
np.outer is a bit cleaner, I suppose, but you can exactly the same
thing you do with matlab if a is a column (single column 2-d array):
In [40]: a = np.arange(4).reshape((-1,1))
In [41]: a
Out[41]:
array([[0],
[1],
[2],
[3]])
In [42]: np.dot(a,a.T)
Out[42]:
array([[0, 0, 0, 0],
[0, 1, 2, 3],
[0, 2, 4, 6],
[0, 3, 6, 9]])
or, of course, 2 arrays to begin with:
In [13]: a = np.arange(4).reshape((4,1))
In [14]: b = np.arange(4).reshape((1,4))
In [15]: np.dot(a,b)
Out[15]:
array([[0, 0, 0, 0],
[0, 1, 2, 3],
[0, 2, 4, 6],
[0, 3, 6, 9]])
-Chris
--
Christopher Barker, Ph.D.
Oceanographer
Emergency Response Division
NOAA/NOS/OR&R (206) 526-6959 voice
7600 Sand Point Way NE (206) 526-6329 fax
Seattle, WA 98115 (206) 526-6317 main reception
chris.bar...@noaa.gov
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