[SciPy-user] Bug in stats?

David Huard david.huard at gmail.com
Tue Jan 24 09:53:05 CST 2006


To use the stats method, try giving it the parameters explicitely, as in
>>> gamma.stats(1.5, loc=4., scale =5.)
(array(11.5), array(37.5))

David

2006/1/24, David Huard <david.huard at gmail.com>:
>
> I answered my own question about genextreme.fit. The problem was that for
> the data set, the default initial value gave an -inf log-likelihood. I
> assume that this perplexes the fmin routine who simply returns the initial
> value.
>
> David
>
> 2006/1/24, David Huard <david.huard at gmail.com>:
> >
> > Hi,
> >
> > I get the same problem, and had it with previous versions of scipy too.
> > Also, I just found out that the fit method of the genextreme distribution
> > returns [1.,0.,1.] systematically, no matter what the data set is.
> >
> > For example,
> > >>> z = genextreme.rvs(.15, loc=3.8, scale=.17, size=30)
> > >>> z
> > array([3.57489347,  3.88036819,  3.78173901,...])
> > >>> genextreme.fit(z)
> > array([ 1.,  0.,  1.])
> >
> > Is it a bug or the stats package is not completed yet ?
> >
> > Thanks
> >
> > David
> >
> > 2006/1/19, Paul Ray <Paul.Ray at nrl.navy.mil>:
> > >
> > > Hi,
> > >
> > > I'm getting nan when I try to calculate the stats on any distribution
> > > In [1]: import scipy
> > > Overwriting fft=<function fft at 0x1458730> from scipy.fftpack.basic
> > > (was <function fft at 0x14478b0> from numpy.dft.fftpack)
> > > Overwriting ifft=<function ifft at 0x1458770> from
> > > scipy.fftpack.basic (was <function inverse_fft at 0x14478f0> from
> > > numpy.dft.fftpack)
> > >
> > > In [2]: scipy.stats.norm.stats()
> > > Out[2]: (nan, nan)
> > >
> > > In [3]: scipy.__version__
> > > Out[3]: '0.4.4'
> > >
> > > I get nan's for all distributions I have tried and the loc and scale
> > > parameters don't seem to help.
> > >
> > > Is this a bug or am I using it wrong?
> > >
> > > Thanks,
> > >
> > > -- Paul
> > >
> > > --
> > > Dr. Paul S. Ray              E-mail: Paul.Ray at nrl.navy.mil
> > > Naval Research Laboratory    WWW   : http://xweb.nrl.navy.mil/
> > > personnel/paulr/
> > > Code 7655                    Phone : (202) 404-1619
> > > Washington, DC 20375         AIM   : NRLPSR
> > >
> > >
> > > _______________________________________________
> > > SciPy-user mailing list
> > > SciPy-user at scipy.net
> > > http://www.scipy.net/mailman/listinfo/scipy-user
> > >
> >
> >
>
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