Re: problem with residue and repeated complex roots

[Doug Stewart]

I downloaded from

http://velveeta.che.wisc.edu/cgi-bin/cvsweb.cgi/~checkout~/octave/scripts/polynomial/residue.m?rev=1.35;content-type=text%2Fplain

and it does use mpoles.m

but I still get

> > [a b c]=residue(n,d)

ver = 1.35

a =

-9.3613e-018 - 9.2593e-003i

-2.7778e-002 - 5.3894e-010i

2.3130e-018 + 9.2593e-003i

-2.7778e-002 + 5.3894e-010i

b =

-2.0000 + 3.0000i

-2.0000 + 3.0000i

-2.0000 - 3.0000i

-2.0000 - 3.0000i

c = [](0x0)

To prove that I was using the new file and not an older file I added a 
line to print out the ver. number.


Please test this on your machine.


Doug Stewart



Doug Stewart wrote:
> Thanks
> Doug
>
> Ben Abbott wrote:
>   
> > Doug,
> >
> > This problem was addressed with a change that made it into 2.9.16. If 
> > you check the cvs you can replace your residue.m with the one there. 
> > You'll need mpoles.m as well.
> >
> > I should also mention that another bug/feature was fixed just yesterday.
> >
> > Ben
> >
> > On Nov 27, 2007, at 5:11 PM, Doug Stewart wrote:
> >
> >     
> > > I am running qtoctave on windows XP octave version 2.9.15
> > > residue doesn't give the correct answer for repeated complex roots
> > >
> > > her is Matlab's result
> > >
> > > » n
> > > n =
> > >      1
> > > » d
> > > d =
> > >      1     8    42   104   169
> > > » roots(d)
> > > ans =
> > >   -2.0000+ 3.0000i
> > >   -2.0000- 3.0000i
> > >   -2.0000+ 3.0000i
> > >   -2.0000- 3.0000i
> > > » [a b c]=residue(n,d)
> > > a =
> > >   1.0e+005 *
> > >    1.2662+ 1.8232i
> > >    1.2662- 1.8232i
> > >   -1.2662- 1.8232i
> > >   -1.2662+ 1.8232i
> > > b =
> > >   -2.0000+ 3.0000i
> > >   -2.0000- 3.0000i
> > >   -2.0000+ 3.0000i
> > >   -2.0000- 3.0000i
> > > c =
> > >      []
> > >
> > > and qtoctave's results
> > >
> > >       
> > > > > n
> > > > >           
> > > n = 1
> > >
> > >       
> > > > > d
> > > > >           
> > > d =
> > >
> > > 1 8 42 104 169
> > >
> > >       
> > > > > roots(d)
> > > > >           
> > > ans =
> > >
> > > -2.0000 + 3.0000i
> > >
> > > -2.0000 - 3.0000i
> > >
> > > -2.0000 + 3.0000i
> > >
> > > -2.0000 - 3.0000i
> > >
> > >       
> > > > > [a b c]=residue(n,d)
> > > > >           
> > > a =
> > >
> > > -9.3613e-018 - 9.2593e-003i
> > >
> > > -2.7778e-002 - 5.3894e-010i
> > >
> > > 2.3130e-018 + 9.2593e-003i
> > >
> > > -2.7778e-002 + 5.3894e-010i
> > >
> > > b =
> > >
> > > -2.0000 + 3.0000i
> > >
> > > -2.0000 + 3.0000i
> > >
> > > -2.0000 - 3.0000i
> > >
> > > -2.0000 - 3.0000i
> > >
> > > c = [](0x0)
> > >
> > >
> > >
> > > I haven't looked into why this is happening yet.
> > >
> > > Doug Stewart
> > >
> > > _______________________________________________
> > > Help-octave mailing list
> > > address@hidden
> > > https://www.cae.wisc.edu/mailman/listinfo/help-octave
> > >       
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