Hi,
Am 2016-10-05 um 01:33 schrieb Thierry:
> Could you reproduce your issue with sufficiently enough other polynomials
> or is it just that one ?
I can offer to more such polynomials:
x = polygen(QQ, 'x')
rho1 = QQbar.polynomial_root(x^7 + 37985/2366*x^6 + 116073/2366*x^5 -
34406/1183*x^4 + 13
Hi,
without exploring deeply, it looks like an unlucky collision with the
shift by the particular QQbar_hash_offset=1/987654321*I+1/123456789 (which
aims to avoid collisions for more usual algebraic numbers like 1 or 2).
sage: from sage.rings.qqbar import QQbar_hash_offset
sage: QQbar_hash_offset
Hashing of QQbar elements seems to be quite inefficient:
sage: R. = AA[]
sage: rho = QQbar.polynomial_root(
: x^5 - 1/3*x^4 + 1/30*x^3 - 1/600*x^2 + 1/24000*x - 1/240,
: CIF(RIF(0.02, 0.03), RIF(-0.009, -0.007)))
sage: %time hash(rho)
CPU times: user 14 s, sys: 36 ms, total: 14
