[Numpy-discussion] Fast vector multiplication

Mark Janikas mjanikas at esri.com
Fri Jan 19 16:40:32 CST 2007


Hello all,

 

I am trying to figure out the most efficient way to get the sum of the
product of two vectors where id != id.

 

E.g.:

 

X = array([1,2,3])

Y = array([1,2,3])

 

Z = (1*2) + (1*3) + (2*1) + (2*3) + (3*1) + (3*2) = 22

 

I could obviously do this with loops, but I was wondering if there is a
version of multiply that could be used... or a form of vectorize.  Any
ideas would be greatly appreciated. 

 

Mark Janikas

Product Engineer

ESRI, Geoprocessing

380 New York St.

Redlands, CA 92373

909-793-2853 (2563)

mjanikas at esri.com

 

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