Opened 12 years ago
Closed 3 years ago
#9707 closed enhancement (fixed)
Add a "signless" option to laplacian
Reported by:  jason  Owned by:  ghrajat1433 

Priority:  major  Milestone:  sage8.7 
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: 
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 DA
(see p. 12 of http://www.doiserbia.nb.rs/ft.aspx?id=035013020795011C, for example).
Thanks to Steve Butler for the feature request.
Change History (12)
comment:1 Changed 9 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:2 Changed 9 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:3 Changed 8 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:4 Changed 8 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:6 Changed 3 years ago by
A quick search effectively returns a significant number of recent publications.
comment:7 Changed 3 years ago by
 Branch set to u/ghrajat1433/9707_signless_laplacian
 Milestone changed from sage6.4 to sage8.7
 Owner changed from jason, ncohen, rlm to ghrajat1433
 Reviewers set to dcoudert
comment:8 Changed 3 years ago by
 Commit set to e2b64c647dfcf613333c1797532289295328b5dd
Branch pushed to git repo; I updated commit sha1. New commits:
e2b64c6  added signless option

comment:9 Changed 3 years ago by
 Status changed from new to needs_review
comment:10 followup: ↓ 11 Changed 3 years ago by
Do i need to include this ticket number somewhere in the code?
comment:11 in reply to: ↑ 10 Changed 3 years ago by
 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
 Branch changed from u/ghrajat1433/9707_signless_laplacian to e2b64c647dfcf613333c1797532289295328b5dd
 Resolution set to fixed
 Status changed from positive_review to closed
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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?
https://arxiv.org/pdf/1803.06135.pdf
http://elib.mi.sanu.ac.rs/files/journals/publ/101/n095p011.pdf
https://ac.elscdn.com/S0024379507000316/1s2.0S0024379507000316main.pdf?_tid=59a3915edd7a4dea87a71892bc82cdca&acdnat=1552416165_1a56db5226e8357d8b7c9879a5dc3973