Yes, this seems like a good option, so keep reducing eps in a while loop until the endpoints of all intervals are different, right?
On Tuesday, May 21, 2024 at 1:55:54 PM UTC-7 asme...@gmail.com wrote: > I don't know if there's an existing option to do this. It seems like > it would be useful. You can always lower the eps to make the intervals > smaller: > > >>> Poly(x**6 + 19/5*x**5 + 131/50*x**4 - x**2 - 19/5*x - 131/50, x, > domain='QQ').intervals(eps=0.1) > [((-29/10, -26/9), 1), ((-1, -1), 1), ((-10/11, -9/10), 1), ((1, 1), 1)] > > Aaron Meurer > > On Tue, May 21, 2024 at 2:51 PM Ani J <ani...@gmail.com> wrote: > > > > > > Oh! I see, but i believe that the intervals overlap on the endpoints, is > it possible to make the intervals completely disjoint?? > > For example consider the following program: > > > > from sympy import Poly > > from sympy.abc import x > > from sympy import div, QQ > > p = Poly(x**6 + 19/5*x**5 + 131/50*x**4 - x**2 - 19/5*x - 131/50, x, > domain='QQ') > > p.intervals() > > > > The intervals that this outputs is: [((-3, -2), 1), ((-1, -1), 1), ((-1, > 0), 1), ((1, 1), 1)] > > > > Here we can see that the point -1 is a common endpoint between the > second and > > > > the third term. Is it possible to enforce that there be no common point? > > > > > > Best > > > > On Tuesday, May 21, 2024 at 10:27:15 AM UTC-7 asme...@gmail.com wrote: > >> > >> Yes, this is the case. The documentation for this method could perhaps > >> be improved, but the key word is "isolating", meaning each interval > >> contains exactly one root. You can also read more about the algorithm > >> that is referenced in the docstring > >> https://en.wikipedia.org/wiki/Vincent%27s_theorem > >> > >> Aaron Meurer > >> > >> > >> On Tue, May 21, 2024 at 9:18 AM Chris Smith <smi...@gmail.com> wrote: > >> > > >> > I strongly suspect that the roots returned by `Poly.intervals` have > only one root in them (by definition). If you use `refine_root(lo,hi,eps)` > to refine the root bounds to arbitrary width and give it an interval in > which there is more than one root, it will raise an error. > >> > > >> > /c > >> > On Tuesday, May 21, 2024 at 6:06:14 AM UTC-5 ani...@gmail.com wrote: > >> >> > >> >> Is it possible to use SymPy library to get intervals (with rational > endpoints) such that there is exactly one root in the interval? I would > like to use an implementation of RRI algorithm for my purpose. I believe > that the interval function does this. Is this correct? Is it guaranteed > that the output intervals are guaranteed to not have any common points? > >> >> > >> >> > >> > -- > >> > You received this message because you are subscribed to the Google > Groups "sympy" group. > >> > To unsubscribe from this group and stop receiving emails from it, > send an email to sympy+un...@googlegroups.com. > >> > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/807f8910-040d-475b-91b6-a5002cedeea0n%40googlegroups.com > . > > > > -- > > You received this message because you are subscribed to the Google > Groups "sympy" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to sympy+un...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/884eb7ff-0762-4771-a81f-930c13dada2dn%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/c987974b-cf39-4c8a-ad0a-579b61778513n%40googlegroups.com.
