Opened 6 years ago
Closed 6 years ago
#16903 closed defect (fixed)
bugfix for database_cremona_ellcurve optional spkg
Reported by:  cremona  Owned by:  

Priority:  minor  Milestone:  sage6.4 
Component:  packages: optional  Keywords:  elliptic curve database 
Cc:  Merged in:  
Authors:  John Cremona  Reviewers:  Volker Braun 
Report Upstream:  N/A  Work issues:  
Branch:  b9125a4 (Commits)  Commit:  b9125a4f258a97358b5aca69f2d44f4ee63b835e 
Dependencies:  Stopgaps: 
Description (last modified by )
The following (requires optional database_cremona_ellcurve) reveals a problem:
sage: CremonaDatabase().largest_conductor() 349999 sage: E = EllipticCurve([0,1,0,141083,20443787]) sage: E.conductor() 246400 sage: E.label() ... RuntimeError: Cremona label not known for Elliptic Curve defined by y^2 = x^3 + x^2  141083*x  20443787 over Rational Field. sage: E = EllipticCurve([0,1,0,16,421]) sage: E.conductor() 252840 sage: E.label() RuntimeError: Cremona label not known for Elliptic Curve defined by y^2 = x^3  x^2  16*x + 421 over Rational Field.
which was reported by Benjamin Matschke and Rafael von Kanel on 20140828. The database files are missing all curves with conductors in the ranges 246400246499 and 252800252899, in total 1455 elliptic curves in 962 isogeny classes. I am making an update to the database_cremona_ellcurve option spkg.
New tarball :
Change History (6)
comment:1 Changed 6 years ago by
comment:2 Changed 6 years ago by
 Description modified (diff)
comment:3 Changed 6 years ago by
 Branch set to u/cremona/ticket/16903
 Commit set to b9125a4f258a97358b5aca69f2d44f4ee63b835e
 Status changed from new to needs_review
After installing the new version:
sage: CremonaDatabase().number_of_curves() 2188263 sage: CremonaDatabase().number_of_isogeny_classes() 1526482
and
sage: E = EllipticCurve([0,1,0,141083,20443787]) sage: E.label() '246400k1' sage: E = EllipticCurve([0,1,0,16,421]) sage: E.label() '252840d1'
New commits:
b9125a4  #16903: new version of database_cremona_ellcurve optional spkg

comment:4 Changed 6 years ago by
 Reviewers set to Volker Braun
 Status changed from needs_review to positive_review
lgtm
comment:5 Changed 6 years ago by
Wow, I am impressed with the speed of that review! Thanks,
John
comment:6 Changed 6 years ago by
 Branch changed from u/cremona/ticket/16903 to b9125a4f258a97358b5aca69f2d44f4ee63b835e
 Resolution set to fixed
 Status changed from positive_review to closed
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In preparing the new database file (the file cremona.db in SAGE_ROOT/local/share/cremona) which is done using the command sage.databases.cremona.build() on the updated tar file I find that I have to change that script, because I have "tidied up" the file structure in the tarball so that the data files are in subdirectories.
It seems sensible to make those changes in the same branch as the ones for the new spkg (updating package version and checksums).
If the new spkg works OK I think that will be good evidence for the new cremona.db file being good.