#23835 closed enhancement (fixed)
Replace Maxima with Pynac/Singular in Expression.factor()
Reported by:  rws  Owned by:  

Priority:  major  Milestone:  sage8.4 
Component:  symbolics  Keywords:  performance 
Cc:  tscrim  Merged in:  
Authors:  Ralf Stephan  Reviewers:  Travis Scrimshaw 
Report Upstream:  N/A  Work issues:  
Branch:  19cff3a (Commits)  Commit:  
Dependencies:  #23950  Stopgaps: 
Description (last modified by )
The default for symbolic factorization should be changed. Maxima as default should be replaced with a call to Pynac's factor()
implementation, which itself uses Singular at the moment. Maxima should be made available via ex.factor(algorithm=...)
.
As an example of performance gain here one of the Fateman benchmarks:
sage: var('a b c k s y z') (a, b, c, k, s, y, z) sage: f = (1+x+y+z)^20+1 sage: g = (f*(f+1)).expand() sage: %time _=g.factor()
This takes 11 seconds on 8.1.beta5 and 3.3 seconds with Pynac factor (identical time using polynomial ring).
Change History (13)
comment:1 Changed 17 months ago by
 Dependencies set to #23861
comment:2 Changed 17 months ago by
 Branch set to u/rws/replace_maxima_with_pynac_singular_in_expression_factor__
comment:3 Changed 17 months ago by
 Commit set to 5157371e406d5686eb9ce21c9a42ffbcde006925
 Dependencies changed from #23861 to pynac0.7.12
comment:4 Changed 17 months ago by
 Description modified (diff)
 Keywords performance added
comment:5 Changed 17 months ago by
 Dependencies changed from pynac0.7.12 to #23950
 Status changed from new to needs_review
comment:6 Changed 16 months ago by
 Commit changed from 5157371e406d5686eb9ce21c9a42ffbcde006925 to e9484ceda20cde440ae5dd9c61cd8346d0a35412
comment:7 Changed 12 months ago by
 Milestone changed from sage8.1 to sage8.2
comment:8 Changed 7 months ago by
 Cc tscrim added
 Milestone changed from sage8.2 to sage8.4
 Reviewers set to Travis Scrimshaw
If you rebase this to 8.4.beta0, I will review it.
comment:9 Changed 6 months ago by
Ping?
comment:10 Changed 6 months ago by
Sorry, due to other work I'm restricting my activities to maintaining Pynac and its upgrade tickets.
comment:11 Changed 6 months ago by
 Branch changed from u/rws/replace_maxima_with_pynac_singular_in_expression_factor__ to u/tscrim/expression_factor23835
 Commit changed from e9484ceda20cde440ae5dd9c61cd8346d0a35412 to 19cff3a90c5996aad903cf82a90ec31a97b8728f
 Status changed from needs_review to positive_review
No problem. It ended up being a trivial rebase. So I am treating this ticket as a needs_review.
While I do not see as big of a speed difference (9.5s to 3.2s), it still is quite an improvement. So positive review.
New commits:
19cff3a  Merge branch 'u/rws/replace_maxima_with_pynac_singular_in_expression_factor__' of git://trac.sagemath.org/sage into u/tscrim/expression_factor23835

comment:12 Changed 6 months ago by
 Branch changed from u/tscrim/expression_factor23835 to 19cff3a90c5996aad903cf82a90ec31a97b8728f
 Resolution set to fixed
 Status changed from positive_review to closed
comment:13 Changed 3 days ago by
 Commit 19cff3a90c5996aad903cf82a90ec31a97b8728f deleted
See #27304 for a follow up (bug in factorization of exponentials).
New commits:
23835: Replace Maxima with Pynac/Singular in Expression.factor()