Opened 4 years ago

Closed 4 years ago

#19247 closed enhancement (fixed)

Two SRG on 243 and 276 vertices

Reported by: ncohen Owned by:
Priority: major Milestone: sage-6.9
Component: graph theory Keywords:
Cc: dimpase Merged in:
Authors: Nathann Cohen Reviewers: Dima Pasechnik
Report Upstream: N/A Work issues:
Branch: 832f5ea (Commits) 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 4 years ago by ncohen

  • Authors set to Nathann Cohen
  • 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 4 years ago by git

  • Commit set to 4b4f98af0e12dd7e996bc9cf2162063ad199406d

Branch pushed to git repo; I updated commit sha1. New commits:

4b4f98atrac #19247: Two SRG on 243 and 276 vertices

comment:3 Changed 4 years ago by dimpase

typo:

@ -3807,7 +3808,7 @@ def MoebiusKantorGraph():
     Returns a Moebius-Kantor Graph.
 
     A Moebius-Kantor 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 4 years ago by git

  • Commit changed from 4b4f98af0e12dd7e996bc9cf2162063ad199406d to f69cab0a4295f51c562993965821ba72bf1d409d

Branch pushed to git repo; I updated commit sha1. New commits:

f69cab0trac #19247: typo

comment:5 follow-up: Changed 4 years ago by 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.

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

Last edited 4 years ago by ncohen (previous) (diff)

comment:6 in reply to: ↑ 5 Changed 4 years ago by dimpase

  • 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 4 years ago by ncohen

Thanks!

Nathann

comment:8 Changed 4 years ago by vbraun

  • Status changed from positive_review to needs_work

Reviewer name

comment:9 Changed 4 years ago by git

  • Commit changed from f69cab0a4295f51c562993965821ba72bf1d409d to 832f5ea636e2fa2318a51f4063aad15a9f5d1937

Branch pushed to git repo; I updated commit sha1. New commits:

832f5eaadded a ref to Haemers & Tonchev and improved English a bit

comment:10 Changed 4 years ago by dimpase

  • 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 4 years ago by ncohen

  • Status changed from needs_review to positive_review

comment:12 Changed 4 years ago by ncohen

Thanks !

comment:13 Changed 4 years ago by vbraun

  • Branch changed from public/19247 to 832f5ea636e2fa2318a51f4063aad15a9f5d1937
  • Resolution set to fixed
  • Status changed from positive_review to closed
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