I think is is easier, both on the eye and for a beginner to
understand:
sage: x = polygen(ZZ)
sage: f = 2*x**2 - x
sage: f.factor()
x * (2*x - 1)
The effect of the first line is that polynomials in x are elements of
the polynomial ring with integer coefficients. Note the difference
when we switch to rational coeffs:
sage: x = polygen(QQ)
sage: f = 2*x**2 - x
sage: f.factor()
(2) * (x - 1/2) * x
Here 2 is the "unit factor" amd the other two are irreducible
polynomials normalised to be monic, which makes sense over a field.
John Cremona
On Jun 17, 7:30 am, Robert Bradshaw <rober...@math.washington.edu>
wrote:
> On Jun 16, 2009, at 3:10 PM, Mikie wrote:
>
>
>
> > Yes, and as you can see it works great in sage command line. When I
> > use it in a python script I get a syntax error for the period in
> > R.<x>.
>
> Clearly you are not using the preparser. What you could do is
>
> x = QQ['x'].gen(0)
> f = 2*x**2 - x
> f.factor()
>
> You can also do
>
> sage: preparse("x = QQ['x'].0")
> "x = QQ['x'].gen(0)"
>
> to see something that'll work in pure Python (assuming the needed
> imports).
>
> - Robert
>
> > On Jun 16, 12:30 pm, David Joyner <wdjoy...@gmail.com> wrote:
> >> Is this what you mean?
>
> >> sage: R.<x> = PolynomialRing(ZZ,"x")
> >> sage: f = 2*x**2-x
> >> sage: f.factor()
> >> x * (2*x - 1)
>
> >> On Tue, Jun 16, 2009 at 11:12 AM,
> >> Mikie<thephantom6...@hotmail.com> wrote:
>
> >>> When I use Sage to factor lets say 2*x**2-x it factors the 2 out
> >>> and
> >>> leaves a fraction in the expression. I would like to have it not
> >>> factor the polynomial unless their is an integer factor. By the
> >>> way I
> >>> have created a Twisted API that works.
>
> >>> On Jun 15, 4:51 pm, William Stein <wst...@gmail.com> wrote:
> >>>> On Mon, Jun 15, 2009 at 10:54 PM,
> >>>> Mikie<thephantom6...@hotmail.com> wrote:
>
> >>>>> Is there anyway to get the factor function to factor an expression
> >>>>> without using QQ['x'].0? I want just integer factors.
>
> >>>> I don't understand what you mean by "integer factors"? Can you
> >>>> give an example?
>
> >>>>> I have created a Twisted server using Sage to do calculations
> >>>>> from a
> >>>>> form.
> >>>>> When I put QQ['x'].0 into the sage script I get a systax on the
> >>>>> period. It does work from the command line.
> >>>>> Thanx
>
> >>>> --
> >>>> William Stein
> >>>> Associate Professor of Mathematics
> >>>> University of Washingtonhttp://wstein.org-Hide quoted text -
>
> >> - Show quoted text -
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