Opened 6 years ago

Closed 6 years ago

#15503 closed defect (fixed)

DegreeSequences(n) returns false positive

Reported by: ppurka Owned by:
Priority: major Milestone: sage-6.1
Component: graph theory Keywords:
Cc: ncohen Merged in:
Authors: Nathann Cohen Reviewers: Punarbasu Purkayastha
Report Upstream: N/A Work issues:
Branch: u/ncohen/15503 (Commits) Commit: fd217a518be20b8dc0fcda19ed30cb4f8ba651c6
Dependencies: Stopgaps:

Description

From google spreadsheet which no one reads X-(

[2,2,2,2,1,1,1] in DegreeSequences(7) 

returns "true."

Change History (14)

comment:1 follow-up: Changed 6 years ago by ncohen

  • Authors set to Nathann Cohen
  • Branch set to u/ncohen/15503
  • Status changed from new to needs_review

Sorryyyyyyyyy T_T

I forgot the first (and easiest) part of this theorem : the sum of all integers must be even. There even was a "S" variable equal to this sum that wasn't even ever used in the code T_T

What is google spreadsheet by the way ?

Nathann

comment:2 Changed 6 years ago by git

  • Commit set to fd217a518be20b8dc0fcda19ed30cb4f8ba651c6

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

fd217a5trac #15503: DegreeSequences?(n) returns false positive

comment:3 in reply to: ↑ 1 ; follow-up: Changed 6 years ago by ppurka

Replying to ncohen:

Sorryyyyyyyyy T_T

I forgot the first (and easiest) part of this theorem : the sum of all integers must be even. There even was a "S" variable equal to this sum that wasn't even ever used in the code T_T

No idea what degree sequences mean :-/

What is google spreadsheet by the way ?

Open your sagenb notebook and on the top right you will see "Report a problem". That goes to a google form. And the bug report gets collected in this google spreadsheet (which no one reads).

comment:4 in reply to: ↑ 3 ; follow-up: Changed 6 years ago by ncohen

No idea what degree sequences mean :-/

Some graph stuff. It's fixed with this patch. You can review it yourself if you want, just notice that on wikipedia the "Erdos-Gallai" theorem begins by saying that the sum of the degrees must be even, and this is exactly what I had forgotten in this patch. Otherwise somebody will probably review it someday ^^;

What is google spreadsheet by the way ?

Open your sagenb notebook and on the top right you will see "Report a problem". That goes to a google form. And the bug report gets collected in this google spreadsheet (which no one reads).

...................... We have this amount of bug reports, and they are just rotting there ?....

T_T

Nathann

comment:5 Changed 6 years ago by ppurka

  • Reviewers set to Punarbasu Purkayastha
  • Status changed from needs_review to positive_review

Given the wikipedia definition, this patch looks correct to me.

EDIT: BTW, this passes all doctests in combinat/degree_sequences.pyx, graphs/generators and graphs/graph_generators.py where the DegreeSequences is used.

Last edited 6 years ago by ppurka (previous) (diff)

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

Replying to ncohen:

Open your sagenb notebook and on the top right you will see "Report a problem". That goes to a google form. And the bug report gets collected in this google spreadsheet (which no one reads).

...................... We have this amount of bug reports, and they are just rotting there ?....

Unfortunately, yes.

comment:7 Changed 6 years ago by ppurka

By the way, I just opened a bunch of bug reports from #15496 to #15504 based on the bug reports in that spreadsheet. If you intend to open any ticket, just check against the ones I have already opened.

comment:8 follow-up: Changed 6 years ago by ncohen

Oh. Can we remove lines from this spreadsheet once they have been translated into trac tickets ?

comment:9 in reply to: ↑ 8 Changed 6 years ago by ppurka

Replying to ncohen:

Oh. Can we remove lines from this spreadsheet once they have been translated into trac tickets ?

No idea which account that google spreadsheet belongs to. Perhaps you can ask on sage-devel.

comment:10 Changed 6 years ago by ncohen

Well we should definitely write about that... T_T

Do you ? Do I ?

Nathann

comment:11 Changed 6 years ago by ppurka

Go ahead. You can make a more dramatic mail than I can ;-) That's probably a good thing in this case!

comment:12 Changed 6 years ago by ncohen

I'm always too dramatic (and aggressive). That's why I wanted too give the guys a rest :-PPP

comment:13 Changed 6 years ago by kcrisman

Eek, I hope that degree sequence wasn't my fault five years ago...

Harald can give you write permissions on this document, guys. And I highly recommend putting some note in the "Comments" field I created a year or two ago that these are opened. If we were really on it we'd even respond to the emailers! Maybe I need to take a month and do this follow-up full time... except I have a day job.

comment:14 Changed 6 years ago by vbraun

  • Resolution set to fixed
  • Status changed from positive_review to closed
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