Opened 12 years ago

Last modified 6 weeks ago

## #11505 new defect

# ideals_of_bdd_norm misterious bug?

Reported by: | mmasdeu | Owned by: | davidloeffler |
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Priority: | minor | Milestone: | |

Component: | number fields | Keywords: | ideallist, ideals of bounded norm, memory |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

Here is a code that I try to run in my laptop:

sage: R.<t>=QQ['x'] sage: F.<a>=NumberField(t^2-t-7) sage: V=F.ideals_of_bdd_norm(150000) sage: assert(len(V[14369])>0) sage: I=F.ideal(V[14369][0]) sage: assert(I.norm()==14369)

The last assertion should not complain, because ideals_of_bdd_norm(N) should return a dict of integral ideals of norm up to N, indexed by the norm.

I have only observed this when I ask for very large norms (I would like to go up to 10e6, and the above is the smallest example that I got). If I ask for norms up to 15000 say, then it works as expected.

I suspect that it is a problem with the communication with pari, but I don't know enough about it to tell. Also, I should say that this doesn't happen in other (bigger) machines that I have tried, so it might be architecture-related, or maybe memory dirtyness...

I am running this on Sage 4.7, on a Thinkpad X41t with an updated Arch distribution, if that is of any help. Also I will be happy to do more tests if asked, of course!

### Change History (6)

### comment:1 Changed 10 years ago by

### comment:2 Changed 9 years ago by

Milestone: | sage-5.11 → sage-5.12 |
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### comment:3 Changed 9 years ago by

Milestone: | sage-6.1 → sage-6.2 |
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### comment:4 Changed 9 years ago by

Milestone: | sage-6.2 → sage-6.3 |
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### comment:5 Changed 9 years ago by

Milestone: | sage-6.3 → sage-6.4 |
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### comment:6 Changed 6 weeks ago by

Milestone: | sage-6.4 |
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I just ran the code and the first assert failed, i.e.

`len(V[14369])`

is 0 for me. And it should be since 14369 is inert in that quadratic field and so is not the norm of an ideal of that field.