Opened 5 years ago

Closed 5 years ago

#19196 closed enhancement (fixed)

LatticePoset: add is_dismantlable()

Reported by: jmantysalo Owned by:
Priority: major Milestone: sage-6.10
Component: combinatorics Keywords:
Cc: kdilks, chapoton Merged in:
Authors: Jori Mäntysalo, Frédéric Chapoton Reviewers: Frédéric Chapoton, Jori Mäntysalo
Report Upstream: N/A Work issues:
Branch: 6ac2e21 (Commits) Commit: 6ac2e219b653b380468205fff51a43a6c168dda4
Dependencies: Stopgaps:

Description

Add is_dismantlable(), maybe with certificate -option, to LatticePoset.

Wait until #19191 gets reviewed, and then crosslink them at #19190, and add to index of functions.

Change History (16)

comment:1 Changed 5 years ago by jmantysalo

  • Branch set to u/jmantysalo/latticeposet__add_is_dismantlable__

comment:2 Changed 5 years ago by jmantysalo

  • Commit set to f9bc731924fd81f33095b3d18cc9920ef9e55dec
  • Status changed from new to needs_review

Here it is. This seems to be quite fast, but I am sure that H.is_connected() can be changed to some digraph function checking if upper is reachable from lower. Optimization can be made later, so I mark this as needs_review.

New commits:

​f9bc731Added function is_dismantlable().

comment:3 Changed 5 years ago by jmantysalo

  • Cc ncohen added
  • Status changed from needs_review to needs_work

Everything seems to be already done in graphs... I CC Nathann because I just noticed at #19118 the function 

g.subgraph(vertices=g.cores(k=2)[1])

So propably there is some very easy way to make this.

comment:4 Changed 5 years ago by jmantysalo

  • Cc ncohen removed
  • Status changed from needs_work to needs_review

Forget. Sorry for the noice.

(Even if .cores() does kind of similar thing, it is not actually useful here. So back to original algorithm and back to needs_review.)

comment:5 Changed 5 years ago by jmantysalo

  • Status changed from needs_review to needs_work

Hmm... If a lattice is not dismantlable, then it contains a "crown". Should certificate return it?

comment:6 Changed 5 years ago by git

  • Commit changed from f9bc731924fd81f33095b3d18cc9920ef9e55dec to b9e73715c8c22f283f068c9675b924faab180ee4

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

​b9e7371Correction of a bug, added negative certificate.

comment:7 Changed 5 years ago by jmantysalo

  • Cc ​aschilling added
  • Status changed from needs_work to needs_review

Anne selected as a random victim for possible review.

comment:8 Changed 5 years ago by kdilks

  • Cc kdilks added

Adding self as victim for possible review...

comment:9 Changed 5 years ago by jmantysalo

  • Status changed from needs_review to needs_work

Needs merge, but I'll wait #19123 to be accepted (or rejected) first.

comment:10 Changed 5 years ago by git

  • Commit changed from b9e73715c8c22f283f068c9675b924faab180ee4 to 00d07b68259a8bbb46d27d7acfced014159648d0

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

​00d07b6Merged with latest beta

comment:11 Changed 5 years ago by git

  • Commit changed from 00d07b68259a8bbb46d27d7acfced014159648d0 to badb4f77b66756a69b3dda76b11ccb548745dbc5

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

​badb4f7Indentation in docstring.

comment:12 Changed 5 years ago by jmantysalo

  • Status changed from needs_work to needs_review

As #19123 is stalled, I merged this. Maybe I got at least some code into next release.

comment:13 Changed 5 years ago by jmantysalo

  • Cc chapoton added; ​aschilling removed
  • Milestone changed from sage-wishlist to sage-6.10

​​​Frédéric? Someone? This is quite easy one.

Would be nice if at 2016-01-07 I could say that this will be at Sage version 6.10. I will mention dismantlable lattices then in a little talk.

comment:14 follow-up: Changed 5 years ago by chapoton

  • Branch changed from u/jmantysalo/latticeposet__add_is_dismantlable__ to public/19196
  • Commit changed from badb4f77b66756a69b3dda76b11ccb548745dbc5 to 6ac2e219b653b380468205fff51a43a6c168dda4

ok, good to go. I have put the code into pep8 standard.

If you approve my small changes, you can set to positive review.

By the way, please avoid the final underscores in your branch names, as it makes rather hard to copy/paste. Better to keep the branch names short and simple, I would say.

New commits:

​8d92005Merge branch 'u/jmantysalo/latticeposet__add_is_dismantlable__' into 6.10.b5
​6ac2e21trac #19196 pep8 code standard

comment:15 in reply to: ↑ 14 Changed 5 years ago by jmantysalo

  • Authors changed from Jori Mäntysalo to Jori Mäntysalo, Frédéric Chapoton
  • Reviewers set to Frédéric Chapoton, Jori Mäntysalo
  • Status changed from needs_review to positive_review

Replying to chapoton:

ok, good to go. I have put the code into pep8 standard.

If you approve my small changes, you can set to positive review.

I did, and also put your name to reviewer field.

By the way, please avoid the final underscores in your branch names, as it makes rather hard to copy/paste. Better to keep the branch names short and simple, I would say.

That this was generated name from git trac, I guess. I will try to use better names from now on. And maybe some day I will remember to use PEP 8 standard...

Thanks - for this, and for many other reviews.

comment:16 Changed 5 years ago by vbraun

  • Branch changed from public/19196 to 6ac2e219b653b380468205fff51a43a6c168dda4
  • Resolution set to fixed
  • Status changed from positive_review to closed
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