LoÃc GreniÃ on Fri, 19 Oct 2012 10:10:55 +0200

 Real roots of a polynomial

• To: pari-dev@pari.math.u-bordeaux.fr
• Subject: Real roots of a polynomial
• From: LoÃc GreniÃ <loic.grenie@gmail.com>
• Date: Fri, 19 Oct 2012 10:10:47 +0200
• Delivery-date: Fri, 19 Oct 2012 10:10:55 +0200
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```    Hello pari developers,

does anybody know any way to obtain the real roots of a
polynomial without computing the non-real ones (potentially
saving time) ? A quick and dirty gp script using Sturm sequence
and Legendre bounds was 35% faster than polroots on a
(single) sample polynomial. Is there any secret pari function
GEN __get_real_roots_of_polynomial_really_fast(GEN P) that
I have not noticed ? If it helps, I only need the roots between two
bounds.

Thanks,

LoÃc

```