Opened 6 years ago
Closed 6 years ago
#19247 closed enhancement (fixed)
Two SRG on 243 and 276 vertices
Reported by:  ncohen  Owned by:  

Priority:  major  Milestone:  sage6.9 
Component:  graph theory  Keywords:  
Cc:  dimpase  Merged in:  
Authors:  Nathann Cohen  Reviewers:  Dima Pasechnik 
Report Upstream:  N/A  Work issues:  
Branch:  832f5ea (Commits, GitHub, GitLab)  Commit:  832f5ea636e2fa2318a51f4063aad15a9f5d1937 
Dependencies:  Stopgaps: 
Description
Two new strongly regular graphs for our database. With a cool and short construction for the 276 instance found by Dima (I'd still be trying otherwise).
Nathann
Change History (13)
comment:1 Changed 6 years ago by
 Branch set to public/19247
 Cc dimpase added
 Component changed from PLEASE CHANGE to graph theory
 Status changed from new to needs_review
 Type changed from PLEASE CHANGE to enhancement
comment:2 Changed 6 years ago by
 Commit set to 4b4f98af0e12dd7e996bc9cf2162063ad199406d
comment:3 Changed 6 years ago by
typo:
@ 3807,7 +3808,7 @@ def MoebiusKantorGraph(): Returns a MoebiusKantor Graph. A MoebiusKantor graph is a cubic symmetric graph. (See also the  Heawood graph). It has 16 nodes and 24 edges. It is nonplanar and + Heawood graph). It haypergrs 16 nodes and 24 edges. It is nonplanar and ^^^^^^^^^ Hamiltonian. It has diameter = 4, girth = 6, and chromatic number = 2. It is identical to the Generalized Petersen graph, P[8,3].
also, I wonder about using sum()
to join lists  should you import it from __builtin__
to overwrite Sage's (symbolic) default?
comment:4 Changed 6 years ago by
 Commit changed from 4b4f98af0e12dd7e996bc9cf2162063ad199406d to f69cab0a4295f51c562993965821ba72bf1d409d
Branch pushed to git repo; I updated commit sha1. New commits:
f69cab0  trac #19247: typo

comment:5 followup: ↓ 6 Changed 6 years ago by
The typo is fixed, and you will notice that it had nothing to do with this branch. Next time you spot a typo in a function which is not related to ticket X, instead of having the author of X fix it for you it would be better manners to add a commit yourself if you care.
About sum: by default in a .py file the 'sum' is Python's sum. The symbolic sum would have to be imported manually, which I did not do.
Nathann
comment:6 in reply to: ↑ 5 Changed 6 years ago by
 Status changed from needs_review to positive_review
Replying to ncohen:
The typo is fixed, and you will notice that it had nothing to do with this branch. Next time you spot a typo in a function which is not related to ticket X, instead of having the author of X fix it for you it would be better manners to add a commit yourself if you care.
well, I didn't have time for this then...
About sum: by default in a .py file the 'sum' is Python's sum. The symbolic sum would have to be imported manually, which I did not do.
same in .pyx ? OK; it seems I'd remove some such imports I did... OK, not here, certainly.
Otherwise, looks good to me.
comment:7 Changed 6 years ago by
Thanks!
Nathann
comment:9 Changed 6 years ago by
 Commit changed from f69cab0a4295f51c562993965821ba72bf1d409d to 832f5ea636e2fa2318a51f4063aad15a9f5d1937
Branch pushed to git repo; I updated commit sha1. New commits:
832f5ea  added a ref to Haemers & Tonchev and improved English a bit

comment:10 Changed 6 years ago by
 Reviewers set to Dima Pasechnik
 Status changed from needs_work to needs_review
please check out the last commit and set the ticket to positive review, unless unhappy...
comment:11 Changed 6 years ago by
 Status changed from needs_review to positive_review
comment:12 Changed 6 years ago by
Thanks !
comment:13 Changed 6 years ago by
 Branch changed from public/19247 to 832f5ea636e2fa2318a51f4063aad15a9f5d1937
 Resolution set to fixed
 Status changed from positive_review to closed
Branch pushed to git repo; I updated commit sha1. New commits:
trac #19247: Two SRG on 243 and 276 vertices