[Numpy-discussion] Floating Point Difference between numpy and numarray
Hanni Ali
hanni.ali@gmail....
Wed Sep 3 05:49:26 CDT 2008
Oh ok, I shall have to find where I did that then. Thanks
2008/9/3 Matthieu Brucher <matthieu.brucher@gmail.com>
> By default, numpy uses float64, but you told it to use float32 ;)
>
> Matthieu
>
> 2008/9/3, Hanni Ali <hanni.ali@gmail.com>:
> > Also can you think of a way either dtype is always float64? I have a lot
> of
> > functions and to add dtype='float64' would require *loads* of testing,
> > whereas if I can set it centrally on the matrix or in the environment
> that
> > would be so much easier.
> >
> > Hanni
> >
> >
> > 2008/9/3 Hanni Ali <hanni.ali@gmail.com>
> > >
> > > Sebastian you legend, that seems to be it.
> > >
> > >
> > > Thank you very much.
> > >
> > > >>> matrix.mean(dtype='float64')
> > > 0.41582015156745911
> > >
> > > What seems odd is that numpy doesn't do this on it's own...
> > >
> > >
> > >
> > >
> > > 2008/9/3 Sebastian Stephan Berg <sebastian@sipsolutions.net>
> > >
> > >
> > >
> > >
> > > > Hi,
> > > >
> > > > just guessing here. But numarray seems to calculate the result in a
> > > > bigger dataype, while numpy uses float32 which is the input arrays
> size
> > > > (at least I thought so, trying it confused me right now ...). In any
> > > > case, maybe the difference will be gone if you
> > > > use .mean(dtype='float64') (or whatever dtype numarray actually uses,
> > > > which seems to be "numarray.MaximumType(a.type())"
> > where a is the array
> > > > to take the mean).
> > > >
> > > > Sebastian
> > > >
> > > >
> > > >
> > > >
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> > >
> > >
> >
> >
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>
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