id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
13100 EllipticCurve_from_j (over QQ) should not always compute minimal twist cremona cremona "Currently when constructing an elliptic curve from a j-invariant over QQ, a curve with minimal conductor is created (the so-called ""minimal twist""). This could be expensive since it involves factoring j and j-1728, so an option to *not* find the minimal twist should be allowed, with the current behaviour as default for backwards compatibility.
For example:
{{{
sage: EllipticCurve(j=2^256+1)
}}}
currently triggers factorization of {{{F_8}}} (which is quite quick) but also {{{F_8-1728}}} (which is not).
Apply [attachment:trac13100-elliptic-rebased.patch]." enhancement closed minor sage-5.3 elliptic curves fixed elliptic curve construction roed vbraun sage-5.3.beta0 John Cremona David Roe N/A #13109