Doh!!! Nice call. Thanks for the input.
MJ ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Timothy Hochberg Sent: Friday, January 19, 2007 2:52 PM To: Discussion of Numerical Python Subject: Re: [Numpy-discussion] Fast vector multiplication On 1/19/07, Mark Janikas <[EMAIL PROTECTED]> wrote: 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. Isn't this just equivalent to: sum(X) * sum(Y) - dot(X, Y) ? If so, I would just use that. -- //=][=\\ [EMAIL PROTECTED]
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