Opened 8 years ago
Closed 8 years ago
#16476 closed enhancement (fixed)
New difference family (25,4,1) and cleanup in bibd.py
Reported by:  Vincent Delecroix  Owned by:  

Priority:  major  Milestone:  sage6.3 
Component:  combinatorial designs  Keywords:  
Cc:  Nathann Cohen  Merged in:  
Authors:  Vincent Delecroix  Reviewers:  Nathann Cohen 
Report Upstream:  N/A  Work issues:  
Branch:  032ee82 (Commits, GitHub, GitLab)  Commit:  032ee826d06ce0241917277938defcc968c38c71 
Dependencies:  #16461  Stopgaps: 
Description (last modified by )
In the construction of Stinson book the BIBD(25,4,1)
comes from a difference family so we can just add it to the database. Moreover the function PBD_4_5_8_9_12
previously failed for v=4,5,8,9,12
where the trivial answer [range(v)]
just fits.
Change History (15)
comment:1 Changed 8 years ago by
Description:  modified (diff) 

Status:  new → needs_review 
comment:2 Changed 8 years ago by
Branch:  → u/vdelecroix/16461 

Commit:  → 8b1e6cefc5d2bae89d9a23c75a78e558ef6d3826 
Last 10 new commits:
f0474bb  trac #16464: be more careful with errors

21cb1a8  trac #16464: handle correctly arguments for cyclotomic_cosets

b07ad01  trac #16464: Second review

136e870  trac #16464: tiny improvements for is_a_splitting

965f550  trac #16464: replace bool(S1&S2) by S1.isdisjoint(S2)

9b199c7  trac #16461: merge #16464

2d12cc0  trac #16461: adapt the implementation with #16464

d3d6a31  trac #16461: reset finite_field_base.pyx to its previous state

2638697  trac #16461: always check the difference family

8b1e6ce  trac #16461: get rid of _nonzero_and_have_distinct_images

comment:3 Changed 8 years ago by
Branch:  u/vdelecroix/16461 → u/vdelecroix/16476 

Commit:  8b1e6cefc5d2bae89d9a23c75a78e558ef6d3826 → ee3b03584f8a60e892734193793dc1c20b6007c0 
Last 10 new commits:
90f828f  trac #16391: use OrthogonalArrayBlockGraph instead of OrthogonalArrayGraph

6e3c685  trac #16391: reviewer's comments

52c2de8  trac #16391: Removing the holes

d0885f7  trac #16391: bugfix

c1de597  trac #16391: doc clean + remove some list construction

41a9a24  trac #16391: Typo

42239cc  trac #16391: Undoing stuff

24ac3a8  trac #16391: Broken doc

70c9805  trac #16391: Merged with #16460

ee3b035  trac #16461: Merged with #16391

comment:4 Changed 8 years ago by
Commit:  ee3b03584f8a60e892734193793dc1c20b6007c0 → 868e0b0a40d0706e599cd60c7fedb013accbfd66 

Branch pushed to git repo; I updated commit sha1. New commits:
868e0b0  trac #16476: new (25,4,1) DF and clean bibd.py

comment:5 followup: 6 Changed 8 years ago by
Good to go ! I wondered about that though... Do we care ? Should we check that the set of block sizes contains integer > 1 ?
sage: from sage.combinat.designs.bibd import _check_pbd sage: _check_pbd([[1],[]],1,[1,0]) ... RuntimeError: This is not a nice honest PBD from the good old days!
Nathann
comment:6 followup: 7 Changed 8 years ago by
Replying to ncohen:
Good to go ! I wondered about that though... Do we care ? Should we check that the set of block sizes contains integer > 1 ?
sage: from sage.combinat.designs.bibd import _check_pbd sage: _check_pbd([[1],[]],1,[1,0]) ... RuntimeError: This is not a nice honest PBD from the good old days!
Actually, it would make more sense to have is_pairwise_balanced_design
in designs_pyx.pyx
... and testing that blocks are nonempty certainly needed! What do you want do be added to that ticket?
comment:7 Changed 8 years ago by
Actually, it would make more sense to have
is_pairwise_balanced_design
indesigns_pyx.pyx
... and testing that blocks are nonempty certainly needed! What do you want do be added to that ticket?
I will add a commit in a second to check this, before we move it to another file.
In the meantime could you check the doc of #16461 ? It does not build on my computer and Volker will set it back to needs_work.
Nathann
comment:9 followup: 10 Changed 8 years ago by
Block of size 1 are not allowed? The Handbook says "Let K be a subset of positive integers"...
comment:10 followup: 11 Changed 8 years ago by
Block of size 1 are not allowed? The Handbook says "Let K be a subset of positive integers"...
What do we do with the PBD with v=1 or v=0 and many sets of size 0,1 ?
Nathann
comment:11 followup: 12 Changed 8 years ago by
Replying to ncohen:
Block of size 1 are not allowed? The Handbook says "Let K be a subset of positive integers"...
What do we do with the PBD with v=1 or v=0 and many sets of size 0,1 ?
Yup. You are right. Makes more sense to exclude them.
Are we happy with this?
comment:12 Changed 8 years ago by
Are we happy with this?
Are you willing to add my commit ?
Nathann
comment:13 Changed 8 years ago by
Branch:  u/vdelecroix/16476 → public/16476 

Commit:  868e0b0a40d0706e599cd60c7fedb013accbfd66 → 032ee826d06ce0241917277938defcc968c38c71 
comment:14 Changed 8 years ago by
Status:  needs_review → positive_review 

comment:15 Changed 8 years ago by
Branch:  public/16476 → 032ee826d06ce0241917277938defcc968c38c71 

Resolution:  → fixed 
Status:  positive_review → closed 
All right, this is rather trivial, but it cleans a bit the bibd stuff.