[Numpy-discussion] Re: reshape and ravel methods of arrays now return views or raise error

Charles R Harris charlesr.harris at gmail.com
Tue Mar 28 22:49:05 EST 2006


Robert,

On 3/28/06, Robert Kern <robert.kern at gmail.com> wrote:
>
> Charles R Harris wrote:
> >
> >
> > On 3/28/06, *Zachary Pincus* <zpincus at stanford.edu
> > <mailto:zpincus at stanford.edu>> wrote:
> >
> >     Let me give a more concrete example, pulled from some code I was
> >     actually using.
> >
> >     The code is obviously a bit flawed, but it worked fine with numpy up
> >     until today. Now it breaks when a and b aren't both c-strided:
> >     def distance_squared(a, b):
> >          return numpy.sum( (a.ravel() - b.ravel())**2 )
> >
> > def distance_squared(a,b)
> >     return ((a - b)**2).sum()
> >
> > The function should probably throw an error if a and b don't have the
> > same shape and order and now it does.
>
> Does it?
>
> In [55]: def distance_squared(a, b):
>    ....:     return ((a - b) ** 2).sum()
>    ....:
>
> In [56]: distance_squared(arange(5), arange(3)[:,newaxis])
> Out[56]: 55


Oops! Guess there should be a test for shape equality in there somewhere.

Chuck
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