Opened 5 years ago
Closed 5 months ago
#23427 closed defect (fixed)
Fix intersection of hyperbolic geodesic arcs
Reported by:  vdelecroix  Owned by:  

Priority:  major  Milestone:  sage9.5 
Component:  geometry  Keywords:  bug 
Cc:  jhonrubia6, slelievre  Merged in:  
Authors:  Javier Honrubia González  Reviewers:  Vincent Delecroix, Dave Morris, Dima Pasechnik 
Report Upstream:  N/A  Work issues:  
Branch:  f3dc878 (Commits, GitHub, GitLab)  Commit:  f3dc8781bfdedf9d269cdea65eead6d67d5b40f1 
Dependencies:  Stopgaps: 
Description (last modified by )
The following geodesic arcs do not intersect but Sage still gives an intersection point.
sage: UHP = HyperbolicPlane().UHP() sage: g1 = UHP.get_geodesic(2*QQbar.gen(), 5) sage: g2 = UHP.get_geodesic(1/2, Infinity) sage: g1.intersection(g2) [Point in UHP 0.500000000000000? + 1.284523257866513?*I]
Change History (29)
comment:1 Changed 5 years ago by
comment:2 Changed 5 years ago by
 Branch set to u/jhonrubia6/intersection_of_hyperbolic_geodesics_is_wrong
comment:3 Changed 5 years ago by
 Commit set to 3f2878194efe7adb432c655c2afcda70c7e33e13
 Status changed from new to needs_review
New commits:
3f28781  Bug corrected. Some examples on perpendicular_bisector() modified as to pass tests

comment:4 followup: ↓ 5 Changed 5 years ago by
What about vertical geodesics?
comment:5 in reply to: ↑ 4 Changed 5 years ago by
 Status changed from needs_review to needs_work
Replying to vdelecroix:
What about vertical geodesics?
More precisely
sage: UHP = HyperbolicPlane().UHP() sage: g1 = UHP.get_geodesic(I, 2*I) sage: g2 = UHP.get_geodesic(I/2, 4*I) sage: g3 = UHP.get_geodesic(3*I, 4*I) sage: g1.intersection(g2) [Boundary point in UHP +Infinity, Boundary point in UHP 0] sage: g1.intersection(g3) [Boundary point in UHP +Infinity, Boundary point in UHP 0]
comment:6 followup: ↓ 7 Changed 5 years ago by
we also need to correct
sage: UHP = HyperbolicPlane().UHP() sage: g1=UHP.get_geodesic(1,+1) sage: g2=UHP.get_geodesic(1,1+2*I) sage: g1.intersection(g2) []
should return
[Boundary point in UHP 1]
and
UHP = HyperbolicPlane().UHP() g1=UHP.get_geodesic(1,I) g2=UHP.get_geodesic(+1,(+cos(pi/3)+I*sin(pi/3))) [Boundary point in UHP 1, Boundary point in UHP 1]
should return []
What should be the correct answer of the function in the following case?
UHP = HyperbolicPlane().UHP() g1=UHP.get_geodesic(I,3*I) g2=UHP.get_geodesic(2*I,4*I)
Maybe
[2*I,3*I]
or
Geodesic in UHP from 2*I to 3*I
comment:7 in reply to: ↑ 6 Changed 5 years ago by
Replying to jhonrubia6:
<SNIP>
What should be the correct answer of the function in the following case?
UHP = HyperbolicPlane().UHP() g1=UHP.get_geodesic(I,3*I) g2=UHP.get_geodesic(2*I,4*I)Maybe
[2*I,3*I]
definitely not
or
Geodesic in UHP from 2*I to 3*I
Much better
comment:8 Changed 6 months ago by
 Commit changed from 3f2878194efe7adb432c655c2afcda70c7e33e13 to 3a07c7e7ceb2cc66f46d96b1f90b7bd574e52640
comment:9 followup: ↓ 11 Changed 6 months ago by
Ideally, work on top of the develop branch (currently Sage 9.5.beta6) rather than master.
comment:10 Changed 6 months ago by
 Cc slelievre added
 Description modified (diff)
 Milestone changed from sage8.1 to sage9.5
 Summary changed from intersection of hyperbolic geodesics is wrong to Fix intersection of hyperbolic geodesic arcs
comment:11 in reply to: ↑ 9 Changed 6 months ago by
Replying to slelievre:
Ideally, work on top of the develop branch (currently Sage 9.5.beta6) rather than master.
Right, I've just noticed, I merge with develop and resubmit
comment:12 Changed 6 months ago by
 Commit changed from 3a07c7e7ceb2cc66f46d96b1f90b7bd574e52640 to 715cbac82d2480b8f4cef5636ce31a58ddfb0282
comment:13 Changed 6 months ago by
However an important new bug appeared when dealing with the intersection in the PD model:
sage: g=HyperbolicPlane().PD().random_geodesic() sage: h = g.perpendicular_bisector().complete() sage: g.intersection(h) []
which is an obvious error. Somehow the problem lies in the abstract method intersection(self, other)
sage: g._cached_geodesic.intersection(h) []
whereas
sage: g._cached_geodesic.intersection(h._cached_geodesic) [Point in UHP 1.27483700342883 + 2.78119562788909*I]
However
sage: g=HyperbolicPlane().PD().random_geodesic() sage: h = g.perpendicular_bisector().complete() sage: g.intersection(h) [Point in UHP 0.815206723839169 + 2.95290895719856*I]
Work in progress
comment:14 Changed 6 months ago by
 Commit changed from 715cbac82d2480b8f4cef5636ce31a58ddfb0282 to 57917b5677c6976112aef0616cd831a25e7e18b9
Branch pushed to git repo; I updated commit sha1. New commits:
57917b5  Bug involving intersection models other tha UHP solved.

comment:15 Changed 6 months ago by
 Commit changed from 57917b5677c6976112aef0616cd831a25e7e18b9 to b0648b27e31c67536205a4fe9c4e85d66adea382
Branch pushed to git repo; I updated commit sha1. New commits:
b0648b2  ll test passed. Bug corrected with asymptotically parallel geodesics

comment:16 Changed 6 months ago by
 Status changed from needs_work to needs_review
comment:17 Changed 6 months ago by
Just merge (or rebase) locally, and push the merged branch.
comment:18 Changed 6 months ago by
Here are the merge conflicts that I see with 9.5b7. They are in the EXAMPLES
sections of the two perpendicular_bisector
methods.
<<<<<<< HEAD sage: h = g.perpendicular_bisector() sage: P = g.plot(color='blue')+h.plot(color='orange');P # optional  sage.plot ======= sage: h = g.perpendicular_bisector().complete() sage: P = g.plot(color='blue')+h.plot(color='orange');P >>>>>>> b0648b27e31c67536205a4fe9c4e85d66adea382
<<<<<<< HEAD sage: h = g.perpendicular_bisector() sage: show(g.plot(color='blue')+h.plot(color='orange')) # optional  sage.plot ======= sage: h = g.perpendicular_bisector().complete() sage: show(g.plot(color='blue')+h.plot(color='orange')) >>>>>>> b0648b27e31c67536205a4fe9c4e85d66adea382
comment:19 Changed 6 months ago by
so just use the lines in HEAD when you resolve the conflict.
comment:20 Changed 6 months ago by
sorry  if these .complete()
things are in the ticket's branch the you need to do the obvious editing.
comment:21 Changed 6 months ago by
 Status changed from needs_review to needs_work
comment:22 Changed 6 months ago by
 Commit changed from b0648b27e31c67536205a4fe9c4e85d66adea382 to 398c65da00edd148b74885773c4df4855f76dbec
Branch pushed to git repo; I updated commit sha1. New commits:
398c65d  merged with develop. Conflicts in EXAMPLES fixed

comment:23 Changed 6 months ago by
 Status changed from needs_work to needs_review
comment:24 Changed 5 months ago by
 Status changed from needs_review to needs_work
clean up is needed:
% tox e pycodestyle  src/sage/geometry/hyperbolic_space/hyperbolic_geodesic.py pycodestyle recreate: /Users/dima/sage/.tox/src pycodestyle runtestpre: PYTHONHASHSEED='3653170419' pycodestyle runtest: commands[0]  tox c /Users/dima/sage/src/tox.ini e pycodestyle  src/sage/geometry/hyperbolic_space/hyperbolic_geodesic.py pycodestyle create: /Users/dima/sage/src/.tox/pycodestyle pycodestyle installdeps: pycodestyle pycodestyle installed: pycodestyle==2.8.0 pycodestyle runtestpre: PYTHONHASHSEED='400015120' pycodestyle runtest: commands[0]  pycodestyle sage/geometry/hyperbolic_space/hyperbolic_geodesic.py sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1043:1: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1045:1: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1155:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1358:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1388:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1395:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1401:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1407:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1413:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1419:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1425:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1431:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1443:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1449:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1455:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1460:25: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1462:9: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1467:9: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1468:9: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1469:42: E261 at least two spaces before inline comment sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1469:43: E262 inline comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1470:20: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1470:43: W291 trailing whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1473:24: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1474:9: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1475:9: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1477:20: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1480:24: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1483:23: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1483:42: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1486:17: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1488:21: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1489:28: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1489:46: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1491:25: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1494:52: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1494:59: E261 at least two spaces before inline comment sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1494:60: E262 inline comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1495:34: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1500:17: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1501:17: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1502:34: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1503:28: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1505:25: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1507:34: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1512:13: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1513:13: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1514:30: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1515:24: E231 missing whitespace after ',' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1518:17: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1532:21: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1533:29: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1537:42: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1537:52: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1537:85: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1537:95: E225 missing whitespace around operator sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:1874:1: W293 blank line contains whitespace sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:2031:13: E741 ambiguous variable name 'I' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:2036:13: E741 ambiguous variable name 'I' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:2143:1: E265 block comment should start with '# ' sage/geometry/hyperbolic_space/hyperbolic_geodesic.py:2145:1: E265 block comment should start with '# ' 14 E225 missing whitespace around operator 9 E231 missing whitespace after ',' 2 E261 at least two spaces before inline comment 2 E262 inline comment should start with '# ' 17 E265 block comment should start with '# ' 2 E741 ambiguous variable name 'I' 1 W291 trailing whitespace 14 W293 blank line contains whitespace ERROR: InvocationError for command /Users/dima/sage/src/.tox/pycodestyle/bin/pycodestyle sage/geometry/hyperbolic_space/hyperbolic_geodesic.py (exited with code 1) ______________________________ summary _______________________________ ERROR: pycodestyle: commands failed ERROR: InvocationError for command /usr/local/bin/tox c src/tox.ini e pycodestyle  src/sage/geometry/hyperbolic_space/hyperbolic_geodesic.py (exited with code 1)
all of these except E741 can be trivially fixed. (Leave E741 as is).
comment:25 Changed 5 months ago by
 Commit changed from 398c65da00edd148b74885773c4df4855f76dbec to f3dc8781bfdedf9d269cdea65eead6d67d5b40f1
Branch pushed to git repo; I updated commit sha1. New commits:
f3dc878  Clean up done leaving E741

comment:26 Changed 5 months ago by
 Status changed from needs_work to needs_review
comment:27 Changed 5 months ago by
 Reviewers set to Dima Pasechnik
 Status changed from needs_review to positive_review
OK, good.
comment:28 Changed 5 months ago by
 Reviewers changed from Dima Pasechnik to Vincent Delecroix, Dave Morris, Dima Pasechnik
comment:29 Changed 5 months ago by
 Branch changed from u/jhonrubia6/intersection_of_hyperbolic_geodesics_is_wrong to f3dc8781bfdedf9d269cdea65eead6d67d5b40f1
 Resolution set to fixed
 Status changed from positive_review to closed
It seems easy. Checking that the real part of the fixed point of both involutions lies between the real part of endpoints of both geodesics,would be a fast implementation. Are you going to tackle this? I have time these days to code it.