maybe numpy.vdot is good for you. In [3]: x = numpy.random.rand(4)
In [4]: x Out[4]: array([ 0.45426898, 0.22369238, 0.98731244, 0.7758774 ]) In [5]: numpy.sqrt(numpy.vdot(x,x)) Out[5]: 1.35394615117 hth, lorenzo On 9/5/07, Robert Dailey <[EMAIL PROTECTED]> wrote: > > Oh I think I get it. > > You mean the built-in len() function? This isn't what I am looking for. > len() returns the number of components in the vector (e.g. whether it is a > 2D, 3D, etc vector). I found that magnitude can be calculated using hypot() > in the math module that comes with python. However, this method only appears > to work with 2D vectors. And yes, by magnitude I mean euclidean norm: > > sqrt( x*x + y*y ) = magnitude (length) of a vector > > On 9/5/07, Robert Dailey <[EMAIL PROTECTED]> wrote: > > > > Thanks for your response. > > > > I was not able to find len() in the numpy documentation at the following > > link: > > http://www.scipy.org/doc/numpy_api_docs/namespace_index.html > > > > Perhaps I'm looking in the wrong location? > > > > On 9/5/07, Matthieu Brucher < [EMAIL PROTECTED] > wrote: > > > > > > > > > > > 2007/9/5, Robert Dailey < [EMAIL PROTECTED]>: > > > > > > > > Hi, > > > > > > > > I have two questions: > > > > > > > > 1) Is there any way in numpy to represent vectors? Currently I'm > > > > using 'array' for vectors. > > > > > > > > > > > > A vector is an array with one dimension, it's OK. You could use a > > > matrix of dimension 1xn or nx1 as well. > > > > > > > > > 2) Is there a way to calculate the magnitude (length) of a vector in > > > > numpy? > > > > > > > > > Yes, len(a) > > > > > > Matthieu > > > > > > _______________________________________________ > > > Numpy-discussion mailing list > > > [email protected] > > > http://projects.scipy.org/mailman/listinfo/numpy-discussion > > > > > > > > > > _______________________________________________ > Numpy-discussion mailing list > [email protected] > http://projects.scipy.org/mailman/listinfo/numpy-discussion > >
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