Re: [sage-support] "Precision too low for generators, not given"

2017-01-05 Thread Jeroen Demeyer
On 2017-01-05 13:17, Erick Knight wrote: Thanks for both of your replies. Just to double check so that I don't have any misunderstanding, PARI is correctly determining whether my ideal is principal, and if it is, it is attempting to produce a generator. It may fail at that, but, since I never a

Re: [sage-support] Re: splitting field vs. Galois closure

2017-01-05 Thread Nils Bruin
On Thursday, January 5, 2017 at 11:27:05 AM UTC-8, John Cremona wrote: > > > I'm tempted to say: beware of memory leaks. Caching an extension on the > base > > field would probably imply that both fields are now participating in a > > reference cycle, anchored in the global UniqueRepresentation

Re: [sage-support] Re: splitting field vs. Galois closure

2017-01-05 Thread John Cremona
On 5 January 2017 at 18:15, Nils Bruin wrote: > On Thursday, January 5, 2017 at 2:27:06 AM UTC-8, John Cremona wrote: >> >> I have a degree 5 polynomial whose Galois group is large (S_5): >> >> sage: x = polygen(QQ) >> sage: f = x^5 - 6*x^3 - x^2 + 6*x - 1 >> >> I can compute its splitting field e

[sage-support] Re: splitting field vs. Galois closure

2017-01-05 Thread Nils Bruin
On Thursday, January 5, 2017 at 2:27:06 AM UTC-8, John Cremona wrote: > > I have a degree 5 polynomial whose Galois group is large (S_5): > > sage: x = polygen(QQ) > sage: f = x^5 - 6*x^3 - x^2 + 6*x - 1 > > I can compute its splitting field easily, thanks to code written by > Jeroen Demeyer I

Re: [sage-support] "Precision too low for generators, not given"

2017-01-05 Thread Erick Knight
Thanks for both of your replies. Just to double check so that I don't have any misunderstanding, PARI is correctly determining whether my ideal is principal, and if it is, it is attempting to produce a generator. It may fail at that, but, since I never ask it for a generator, this produces no

Re: [sage-support] embedding of number field element encapseled in symbolic ring

2017-01-05 Thread Dima Pasechnik
to me this looks an unimplemented feature of SR; basically, you want SR to be able to manipulate algebraic numbers with a specified embedding in the same ring with transcendental functions. (perhaps Mathematica does support this, although I'm not 100% sure) On Thursday, January 5, 2017 at 10:29

Re: [sage-support] embedding of number field element encapseled in symbolic ring

2017-01-05 Thread Daniel Krenn
On 2017-01-05 11:29, Daniel Krenn wrote: > On 2017-01-05 10:55, Daniel Krenn wrote: >> as there is no *canonical* coercion as no embedding of the number field >> is specified. >> >> How can I specify this embedding such that it is used e.g. for the >> symbolic I? > > This looks weird: I is defined

Re: [sage-support] embedding of number field element encapseled in symbolic ring

2017-01-05 Thread Daniel Krenn
On 2017-01-05 10:55, Daniel Krenn wrote: > as there is no *canonical* coercion as no embedding of the number field > is specified. > > How can I specify this embedding such that it is used e.g. for the > symbolic I? This looks weird: I is defined in sage.libs.pynac.pynac via K = QuadraticFiel

[sage-support] splitting field vs. Galois closure

2017-01-05 Thread John Cremona
I have a degree 5 polynomial whose Galois group is large (S_5): sage: x = polygen(QQ) sage: f = x^5 - 6*x^3 - x^2 + 6*x - 1 I can compute its splitting field easily, thanks to code written by Jeroen Demeyer I believe: sage: %time L = f.splitting_field(names='b') CPU times: user 1min 1s, sys: 272

[sage-support] embedding of number field element encapseled in symbolic ring

2017-01-05 Thread Daniel Krenn
I want to take an number field element embedded in the symbolic ring like the imaginary I and add it to an algebraic number: sage: I.pyobject() + QQbar(sqrt(2)) This results in TypeError: unsupported operand parent(s) for '+': 'Number Field in I with defining polynomial x^2 + 1' and 'Algebrai

Re: [sage-support] "Precision too low for generators, not given"

2017-01-05 Thread John Cremona
On 5 January 2017 at 09:27, Jeroen Demeyer wrote: > Sorry, I was wrong. I actually looked at the PARI source code this time and > the warning comes from the bnfisprincipal() function to determine the class > of a given ideal in the class group (so, in particular, it can be used to > check whether

Re: [sage-support] "Precision too low for generators, not given"

2017-01-05 Thread Jeroen Demeyer
Sorry, I was wrong. I actually looked at the PARI source code this time and the warning comes from the bnfisprincipal() function to determine the class of a given ideal in the class group (so, in particular, it can be used to check whether an ideal is principal). This function can also compute

[sage-support] Re: "Integer is not iterable"

2017-01-05 Thread Fjordforsk A/S
Strange, did you use the commas instead of the dots on the squareroots? I tried with the others suggestions and it worked out. onsdag 4. januar 2017 17.24.03 UTC+1 skrev Dima Pasechnik følgende: > > This works for me after I defined cmsel as you did in your previous posts. > > On Wednesday, Janu

Re: [sage-support] "Precision too low for generators, not given"

2017-01-05 Thread John Cremona
On 4 January 2017 at 20:31, Jeroen Demeyer wrote: > I think it means that PARI didn't compute the unit group for certain number > fields. Since you don't need the unit group, I see no issue. >From what I know of the algorithm used -- and one should ask the pari list to be certain -- it computed h