Opened 12 years ago

Closed 3 years ago

#9707 closed enhancement (fixed)

Add a "signless" option to laplacian

Reported by: jason Owned by: gh-rajat1433
Priority: major Milestone: sage-8.7
Component: graph theory Keywords:
Cc: ncohen, rlm, dcoudert Merged in:
Authors: Rajat Mittal Reviewers: David Coudert
Report Upstream: N/A Work issues:
Branch: e2b64c6 (Commits, GitHub, GitLab) Commit: e2b64c647dfcf613333c1797532289295328b5dd
Dependencies: Stopgaps:

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Description

We should have an option to g.laplacian() to return the signless Laplacian, which is attracting attention these days, and which is calculated by D+A instead of D-A (see p. 12 of ​http://www.doiserbia.nb.rs/ft.aspx?id=0350-13020795011C, for example).

Thanks to Steve Butler for the feature request.

Change History (12)

comment:1 Changed 9 years ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:2 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:3 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.2 to sage-6.3

comment:4 Changed 8 years ago by vbraun_spam

  • Milestone changed from sage-6.3 to sage-6.4

comment:5 Changed 3 years ago by gh-rajat1433

  • Cc dcoudert added

Signless laplacian is indeed gaining popularity as evident in the papers below. So can I add the option to the current Laplacian Matrix method to return signless laplacian matrix?

​http://elib.mi.sanu.ac.rs/files/journals/publ/101/n095p011.pdf

​https://ac.els-cdn.com/S0024379507000316/1-s2.0-S0024379507000316-main.pdf?_tid=59a3915e-dd7a-4dea-87a7-1892bc82cdca&acdnat=1552416165_1a56db5226e8357d8b7c9879a5dc3973

Version 0, edited 3 years ago by gh-rajat1433 (next)

comment:6 Changed 3 years ago by dcoudert

A quick search effectively returns a significant number of recent publications.

comment:7 Changed 3 years ago by gh-rajat1433

  • Authors set to Rajat Mittal
  • Branch set to u/gh-rajat1433/9707_signless_laplacian
  • Milestone changed from sage-6.4 to sage-8.7
  • Owner changed from jason, ncohen, rlm to gh-rajat1433
  • Reviewers set to dcoudert

comment:8 Changed 3 years ago by git

  • Commit set to e2b64c647dfcf613333c1797532289295328b5dd

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

​e2b64c6added signless option

comment:9 Changed 3 years ago by gh-rajat1433

  • Status changed from new to needs_review

comment:10 follow-up: Changed 3 years ago by gh-rajat1433

Do i need to include this ticket number somewhere in the code?

comment:11 in reply to: ↑ 10 Changed 3 years ago by dcoudert

  • Reviewers changed from dcoudert to David Coudert
  • Status changed from needs_review to positive_review

We usually add ticket number when we fix a bug. So it's not needed here.

LGTM.

comment:12 Changed 3 years ago by vbraun

  • Branch changed from u/gh-rajat1433/9707_signless_laplacian to e2b64c647dfcf613333c1797532289295328b5dd
  • Resolution set to fixed
  • Status changed from positive_review to closed
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