Opened 10 years ago
Last modified 2 months ago
#11564 new enhancement
Implement polyhedron unfolding (i.e net) for 3polytopes
Reported by:  QuantumKing  Owned by:  mhampton 

Priority:  major  Milestone:  sage9.4 
Component:  geometry  Keywords:  unfolding, net 
Cc:  moritz, jipilab, ghkliem  Merged in:  
Authors:  Mara Kortenkamp  Reviewers:  JeanPhilippe Labbé 
Report Upstream:  N/A  Work issues:  
Branch:  u/ghmarakortenkamp/poly_net (Commits, GitHub, GitLab)  Commit:  9d4f22788cc1feafd12a03131f10a6390a9ec40e 
Dependencies:  Stopgaps: 
Description (last modified by )
An unfolding or a net of a polyhedron is an arrangement of edgejoined polygons in the plane which can be folded (along edges) to become the faces of the polyhedron.
There might be an overlap between polygons (this is an open problem).
This ticket implement ...
Attachments (2)
Change History (19)
Changed 10 years ago by
comment:1 Changed 10 years ago by
comment:2 Changed 10 years ago by
It would be great also to handle higher dimensions, i.e. unfolding a 4d polytope into 3d...
comment:3 Changed 10 years ago by
How does the code look? Any ideas to make it better would be appreciated
comment:4 Changed 10 years ago by
Sorry, I am traveling right now and its hard to find time for Sage development. I do have some comments though.
Not all the functions in your patch have documentation/doctests. These are mandatory for every function, so they need to be added.
I think it will make sense to merge our efforts. I haven't completely fixed up my student's effort but I am attaching the current state so you can take a look at what we did. There are different strengths and weaknesses in our efforts. Ours can handle tougher problems, but we don't have a function to check for overlaps.
If you haven't looked at the master's thesis of Schlickenrieder (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.28.2631&rep=rep1&type=pdf) I highly recommend it. It was based on his work that my student choose to implement the steepestedge algorithm.
A good test problem is what Schlickenrieder calls "turtles", for example:
tpoints = [[i,j,i^2+j^2] for i in srange(5,6,1) for j in srange(5,6,1)] tp = Polyhedron(vertices=tpoints)
comment:5 Changed 9 years ago by
What's the status on this thing? I think it would be nice to have in sage...
comment:6 Changed 9 years ago by
My status is that I am too busy with other duties to finish this off, although I would really like to.
The code in my "trac_11564_preliminary_effort.patch" patch is from a student project. It works, but it could really use some refactoring.
Its possible I would find time to put more effort into this over my winter vacation, but don't count on it. Otherwise, if no one else works on it I would hope to tackle it in the spring or summer.
As I mentioned before, your code mainly needed full documentation (doctests). While it would be nice if it could handle some tough cases, for this kind of functionality something is better than nothing so feel free to finish your version up and I should be able to find time to review it.
comment:7 Changed 8 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:8 Changed 7 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:9 Changed 7 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:10 Changed 7 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:11 Changed 4 years ago by
 Cc moritz added
comment:12 Changed 8 months ago by
 Branch set to u/ghmarakortenkamp/poly_net
 Cc jipilab ghkliem added
 Commit set to c353bce99541d6e992ea134744bf130e32ffaf18
comment:13 Changed 8 months ago by
 Commit changed from c353bce99541d6e992ea134744bf130e32ffaf18 to 6f9867c697296d36f54a1db23c5f31cd5280592c
Branch pushed to git repo; I updated commit sha1. New commits:
6f9867c  Unfolding class

comment:14 Changed 7 months ago by
Here are a few things to fix:
 Is the function
faceorder
used? It doesn't seem so.  In the description of `faceorder I would say:
Return a linear ordering of the edges in a spanning tree for the facet adjacency graph of `poly`.
 Many comments are in German: it would be good to have them in English.
 Many OUTPUT and EXAMPLES are missing.
 Many lines contain (likely old) "Versuch". They should be deleted once every works well...
 Class Unfolding needs docstring for the class and its methods
 Some conventions should be checked (spaces around
=
>=
and such...
I know it is a bit premature for me to give feedback, but it can be used later for a checklist.
I guess also there should be a method in base.py
called something like def unfolding(...):
that will return the picture?
comment:15 Changed 7 months ago by
 Description modified (diff)
 Milestone changed from sage6.4 to sage9.3
 Reviewers set to JeanPhilippe Labbé
 Summary changed from Implement polyhedron unfolding (i.e net) to Implement polyhedron unfolding (i.e net) for 3polytopes
Once the ticket is more advanced, it would be good to complete the description...
comment:16 Changed 4 months ago by
 Milestone changed from sage9.3 to sage9.4
Setting new milestone based on a cursory review of ticket status, priority, and last modification date.
comment:17 Changed 2 months ago by
 Commit changed from 6f9867c697296d36f54a1db23c5f31cd5280592c to 9d4f22788cc1feafd12a03131f10a6390a9ec40e
Branch pushed to git repo; I updated commit sha1. New commits:
9d4f227  added examples

Funny timing, I was about to create a ticket with solution for this same issue. It was the outcome of an undergraduate research project. I will try to review your solution, maybe it is possible to merge the two approaches.