Opened 5 years ago
Closed 4 years ago
#13163 closed defect (fixed)
E.minimal_model() crashes with large coefficients.
Reported by: | weigandt | Owned by: | cremona |
---|---|---|---|
Priority: | major | Milestone: | sage-6.1 |
Component: | elliptic curves | Keywords: | minimal model |
Cc: | Merged in: | ||
Authors: | Jeroen Demeyer | Reviewers: | John Cremona |
Report Upstream: | N/A | Work issues: | |
Branch: | u/jdemeyer/ticket/13163 (Commits) | Commit: | 6092e94a35148a4d1b82d32c0ed945fea634d009 |
Dependencies: | Stopgaps: |
Description
This code
E=EllipticCurve([4382696457564794691603442338788106497, 28, 3992, 16777216, 298]) E.minimal_model()
Spits out this error:
Traceback (most recent call last): File "<stdin>", line 1, in <module> File "_sage_input_23.py", line 10, in <module> exec compile(u'open("___code___.py","w").write("# -*- coding: utf-8 -*-\\n" + _support_.preparse_worksheet_cell(base64.b64decode("RT1FbGxpcHRpY0N1cnZlKFs0MzgyNjk2NDU3NTY0Nzk0NjkxNjAzNDQyMzM4Nzg4MTA2NDk3LCAyOCwgMzk5MiwgMTY3NzcyMTYsIDI5OF0pCkUubWluaW1hbF9tb2RlbCgp"),globals())+"\\n"); execfile(os.path.abspath("___code___.py")) File "", line 1, in <module> File "/tmp/tmpQWTtgb/___code___.py", line 4, in <module> exec compile(u'E.minimal_model() File "", line 1, in <module> File "/sagenb/sage_install/sage-5.0-boxen-x86_64-Linux/local/lib/python2.7/site-packages/sage/schemes/elliptic_curves/ell_rational_field.py", line 2552, in minimal_model F = self.pari_mincurve() File "/sagenb/sage_install/sage-5.0-boxen-x86_64-Linux/local/lib/python2.7/site-packages/sage/schemes/elliptic_curves/ell_rational_field.py", line 713, in pari_mincurve e = self.pari_curve(prec) File "/sagenb/sage_install/sage-5.0-boxen-x86_64-Linux/local/lib/python2.7/site-packages/sage/schemes/elliptic_curves/ell_rational_field.py", line 664, in pari_curve self._pari_curve[prec] = pari(list(self.a_invariants())).ellinit(precision=prec) File "gen.pyx", line 10416, in sage.libs.pari.gen._pari_trap (sage/libs/pari/gen.c:49843) sage.libs.pari.gen.PariError: precision too low (10)
It looks like the precision needs to be increased when such a large curve is fed to PARI's minimal model algorithm.
Change History (5)
comment:1 Changed 4 years ago by
- Milestone changed from sage-5.11 to sage-5.12
comment:2 Changed 4 years ago by
- Branch set to u/jdemeyer/ticket/13163
- Created changed from 06/25/12 18:04:12 to 06/25/12 18:04:12
- Modified changed from 08/13/13 15:35:53 to 08/13/13 15:35:53
comment:3 Changed 4 years ago by
- Commit set to 6092e94a35148a4d1b82d32c0ed945fea634d009
- Status changed from new to needs_review
comment:4 Changed 4 years ago by
- Reviewers set to John Cremona
- Status changed from needs_review to positive_review
I think I might have been the person who first implemented the variable precision for pari curve construction, and did not do a perfect job. This looks pretty good to me.
comment:5 Changed 4 years ago by
- Resolution set to fixed
- Status changed from positive_review to closed
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New commits:
Increase precision if needed in E.pari_curve()