Re: [sage-support] Is it normal to get negative canonical height of a point on EC over NF ?
The problem is indeed fixed by applying #13951 (which still needs reviewing). Peter Op vrijdag 8 november 2013 17:35:01 UTC schreef John Cremona: On 8 November 2013 16:11, Georgi Guninski guni...@guninski.comjavascript: wrote: I am not an expert, but is it normal to get negative canonical height of a point on elliptic curve over number field? No, this is certainly an error. There is at least one outstanding patch relating to heights over number fields (#13951) but also there was a numerical instability problem fixed at #12509 which was not done perfectly (I know, I did it) and that might be the issue here too. Heights are supposed to be independent of the base field. Your curve and point are defined over Q where the height is computed as 0.0324132522964454 -- this uses a completely different implementation (in the pari library) which is more reliable, unfortunately. John Cremona sage: Z1.Z=ZZ[];Nf.v=NumberField(Z**16-2);E=EllipticCurve(Nf,[-87, 504, -40320, 0, 0]);P=E(0,0) sage: P.height() #not very fast -0.150688795814905 sage: P.height(precision=2000) -0.15068879581490624...snip Works on cloud.sagemath too. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support...@googlegroups.com javascript:. To post to this group, send email to sage-s...@googlegroups.comjavascript:. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-support] Is it normal to get negative canonical height of a point on EC over NF ?
On 22 November 2013 17:46, Peter Bruin pjbr...@gmail.com wrote: The problem is indeed fixed by applying #13951 (which still needs reviewing). As Peter and I are both already authors and reviewers of the patcheson that ticket, we should probably find a third party to finish the review. John Peter Op vrijdag 8 november 2013 17:35:01 UTC schreef John Cremona: On 8 November 2013 16:11, Georgi Guninski guni...@guninski.com wrote: I am not an expert, but is it normal to get negative canonical height of a point on elliptic curve over number field? No, this is certainly an error. There is at least one outstanding patch relating to heights over number fields (#13951) but also there was a numerical instability problem fixed at #12509 which was not done perfectly (I know, I did it) and that might be the issue here too. Heights are supposed to be independent of the base field. Your curve and point are defined over Q where the height is computed as 0.0324132522964454 -- this uses a completely different implementation (in the pari library) which is more reliable, unfortunately. John Cremona sage: Z1.Z=ZZ[];Nf.v=NumberField(Z**16-2);E=EllipticCurve(Nf,[-87, 504, -40320, 0, 0]);P=E(0,0) sage: P.height() #not very fast -0.150688795814905 sage: P.height(precision=2000) -0.15068879581490624...snip Works on cloud.sagemath too. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support...@googlegroups.com. To post to this group, send email to sage-s...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
Re: [sage-support] Is it normal to get negative canonical height of a point on EC over NF ?
On 2013-11-22 20:52, John Cremona wrote: On 22 November 2013 17:46, Peter Bruin pjbr...@gmail.com wrote: The problem is indeed fixed by applying #13951 (which still needs reviewing). As Peter and I are both already authors and reviewers of the patcheson that ticket, we should probably find a third party to finish the review. Or you could review each other's work. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
[sage-support] Is it normal to get negative canonical height of a point on EC over NF ?
I am not an expert, but is it normal to get negative canonical height of a point on elliptic curve over number field? sage: Z1.Z=ZZ[];Nf.v=NumberField(Z**16-2);E=EllipticCurve(Nf,[-87, 504, -40320, 0, 0]);P=E(0,0) sage: P.height() #not very fast -0.150688795814905 sage: P.height(precision=2000) -0.15068879581490624...snip Works on cloud.sagemath too. -- You received this message because you are subscribed to the Google Groups sage-support group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/groups/opt_out.
