Nice example! I see your point. However, I wonder. The matrix inversion should cause the same problem, but it is implemented for the symbolic ring. What is different?
Best wishes Michael Am Sonntag, 27. Oktober 2019 05:28:12 UTC+1 schrieb vdelecroix: > > > > Le 24/10/2019 à 09:53, Simon King a écrit : > > On 2019-10-24, Michael Jung <mic...@uni-potsdam.de <javascript:>> > wrote: > >> Do you have an example where SR fails to be exact? > > > > One can convert a float to SR. The result is in SR, but still behaves > > like a float: > > sage: a = SR(2.)^(1/500) > > sage: a^500 > > 2.00000000000005 > > sage: a.parent() > > Symbolic Ring > > This was an easy one. The following shows that SR is just > broken.... pi is rational! > > sage: q = continued_fraction(pi).convergent(100) > sage: q > 8736149038303113005348154524599771853409352442745266/2780802606066896232581239559281727773240004199722661 > > > sage: bool(pi == q) > True > > And everything is with exact numbers. > > Vincent > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/86d3f78b-c7ad-4612-a9ec-c6fc2fd566e4%40googlegroups.com.
