Re: bug with complex coefficient polynomials

[Igor Schein <igor@txc.com>]

On Tue, Dec 08, 1998 at 11:44:58AM -0500, Igor Schein wrote:
> On Tue, Dec 08, 1998 at 11:13:25AM -0500, Karim BELABAS wrote:
> > 
> > [Igor:]
> > > ? factor(x^2-I)
> > >   ***   segmentation fault: bug in GP (please report).
> > 
> > This one was hard to correct... I had introduced two different bugs when
> > trying
> [snip]
> 
> There's another problem remaining after applying the patch:
> 
> ? factorback(factor(polcyclo(10)+I*polcyclo(15)))
> 1
> 
> This one looks bizarre, because if I just factor first, and then apply
> factorack() to %, it works.
> 
> Thanks
> Igor

No, it doesn't look bizarre, but rather like a pretty trivial bug now, because:

? factor(polcyclo(10)+I*polcyclo(15))

[x^8 - x^7 + x^5 + (-1 - I)*x^4 + (1 + I)*x^3 - I*x^2 + (-1 + I)*x + (1 - I) 0]

The degree of the factor is reported as 0, so no wonder it factors back to 1 :)

Igor