Polyfit

[Charles R Harris]

On 10/12/06, Greg Willden <gregwillden at gmail.com> wrote:
>
> On 10/12/06, Charles R Harris <charlesr.harris at gmail.com> wrote:
> >
> > I'm guessing that the rcond number in the lstsq version (default 1e-10)
> > is the difference. Generally the lstsq version should work better than the
> > MPL version because at*a is not as well conditioned and vandermonde matrices
> > are notoriously ill conditioned anyway for higher degree fits. It would help
> > if you attached the data files in ascii form unless they happen to contain
> > thousands of data items. Just the x will suffice, zip it up if you have to.
> >
>
>
> Here are the files.
>
> Since the two algorithms behave differently and each has it place then can
> both be included in numpy?
> i.e. numpy.polyfit(x,y,N, mode='alg1')
> numpy.polyfit (x,y,N, mode='alg2')
>
> replacing alg1 and alg2 with meaningful names.
>

The polyfit function looks seriously busted. If I do the fits by hand I get
the same results using the (not so hot) MPL version or lstsq. I don't know
what the problem is. The docstring is also incorrect for the method. Hmmm...

Chuck
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/numpy-discussion/attachments/20061012/18328d1e/attachment.html>
-------------- next part --------------
-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
-------------- next part --------------
_______________________________________________
Numpy-discussion mailing list
Numpy-discussion at lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/numpy-discussion