Hi, On Fri, Mar 4, 2011 at 8:19 AM, Daniel Hyams <dhy...@gmail.com> wrote:
> This is probably so easy, I'm embarrassed to ask it...but I've been casting > around trying things to no avail for the last hour and a half, so here > goes... > > I have a lot of dot products to take. The length-3 vectors that I want to > dot are stacked in a 2D array like this: > > U = [u1 u2 u3....] > > and > > V = [v1 v2 v3....] > > So both of these arrays, are, say, 3x100 each. I just want to take the dot > product of each of the corresponding vectors, so that the result is > > [u1.v1 u2.v2 u3.v3 ....] > > which would be a 1x100 array in this case. > > Which function do I need to use? I thought tensordot() was the one, but I > couldn't make it work....pure user error I'm sure. > No function needed for this case, just: In []: x= rand(3, 7) In []: y= rand(3, 7) In []: d= (x* y).sum(0) In [490]: d Out[490]: array([ 1.25404683, 0.19113117, 1.37267133, 0.74219888, 1.55296562, 0.15264303, 0.72039922]) In [493]: dot(x[:, 0].T, y[:, 0]) Out[493]: 1.2540468282421895 Regards, eat > > > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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