[Numpy-discussion] linear algebra help
Charles R Harris
charlesr.harris@gmail....
Mon May 18 09:55:30 CDT 2009
2009/5/18 Stéfan van der Walt <stefan@sun.ac.za>
> 2009/5/18 Sebastian Walter <sebastian.walter@gmail.com>:
> > B = numpy.dot(A.T, A)
>
> This multiplication should be avoided whenever possible -- you are
> effectively squaring your condition number.
>
Although the condition number doesn't mean much unless the columns are
normalized. Having badly scaled columns can lead to problems with lstsq
because of its default cutoff based on the condition number.
Chuck
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