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Re: Dot Product of Vectors

On 24 May 2008, at 16:55, Gregory Lypny wrote:

> Hello everyone,
> I've got two n x k matrices called X and Y.  I'd like to compute an n
> x 1 vector whose elements are the dot products of corresponding rows
> of X and Y, that is,
> 	{{X[[1]].Y[[1]]}, {X[[2]].Y[[2]]}, {X[[3]].Y[[3]]}, ...
> {X[[n]].Y[[n]]}.
> I found that this can be done using MapThread as
> 	MapThread[Dot, { X, Y}],
> which is straightforward.  I'm curious, given that there a zillion
> ways to do any given calculation in Mathematica, if anyone knows of
> another way that is as compact.
> Regards,
> 	Gregory

Total[X*Y, {2}]

Andrzej Kozlowski

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