Opened 5 years ago
Closed 3 years ago
#23946 closed enhancement (fixed)
Exhaust over Weil polynomials
Reported by:  Kiran Kedlaya  Owned by:  

Priority:  minor  Milestone:  sage9.1 
Component:  number theory  Keywords:  Weil polynomials, sd91 
Cc:  David Roe  Merged in:  
Authors:  Kiran Kedlaya  Reviewers:  David Roe 
Report Upstream:  N/A  Work issues:  
Branch:  e02ae3c (Commits, GitHub, GitLab)  Commit:  e02ae3cfc9bd4da34ee8f3b3b9a9b94e7666fa6f 
Dependencies:  #24016  Stopgaps: 
Description
I have reasonably stable code (mostly in C, depending on FLINT) for exhausting over Weil polynomials:
https://github.com/kedlaya/rootunitary
The goal of this ticket is to incorporate this code into Sage in some fashion.
Change History (50)
comment:1 followup: 2 Changed 5 years ago by
Dependencies:  → #24016 

comment:2 Changed 5 years ago by
Replying to kedlaya:
In the meantime, I'd appreciate some feedback about where this might belong in Sage.
First of all, your github repo contains both C code and .sage
files. Are the .sage
files considered to be part of your package or are they really only use cases/examples/tests/documentation?
There are two possibilities, each with its advantages and disadvantages:
(A) Make it an external (presumably optional) package and interface it from Sage.
(B) Make it actually a part of Sage itself.
Advantages of (A) are that you keep control of the package: you can easily change the package at will (with (B) every change would need to go through the Sage Trac) and you don't need to care about Sage coding standards. Also important: with (A) your package could be used without Sage. With (B), there might be more initial work needed to get it into Sage but then it might be less work to maintain.
comment:3 Changed 5 years ago by
I just merged a pull request in from another branch, which has the effect of significantly reconfiguring the file structure. In particular, there are no longer any .sage
files in the main directory; the ones that exist are all in subdirectories and are indeed examples/tests.
The main code base now consists of two .c
files (and their .h
headers) and one .pyx
file. I still don't have any sort of independent build structure set up; moreover, the .pyx
file is more than just a simple wrapper, it is where the parallelism is currently implemented. So at the moment there is really no way to use the code without Sage, and I don't particularly intend to work on making that possible. (Exception: if someone wants to use the code from some other platform like Julia, I'd be willing to cooperate with that.)
comment:4 followup: 5 Changed 5 years ago by
I think that the code is stable enough that we should just add it to Sage. Maybe create a folder sage/rings/polynomial/weil/
and put them in there?
comment:5 followup: 6 Changed 5 years ago by
Replying to roed:
I think that the code is stable enough that we should just add it to Sage. Maybe create a folder
sage/rings/polynomial/weil/
and put them in there?
Do you mean put everything in there? Or put the Cython in sage/rings/polynomials/weil_polynomials.pyx
and the C files in sage/rings/polynomial/weil
?
Also, if someone can point me to some guidance about a module to the Sage library (e.g., how to format __init__.py
and all.py
and the like to make the new code discoverable), that would be helpful.
comment:6 Changed 5 years ago by
Replying to kedlaya:
Replying to roed:
I think that the code is stable enough that we should just add it to Sage. Maybe create a folder
sage/rings/polynomial/weil/
and put them in there?Do you mean put everything in there? Or put the Cython in
sage/rings/polynomials/weil_polynomials.pyx
and the C files insage/rings/polynomial/weil
?
I meant putting everything in there. We should also talk about the best way for a user to access these methods; perhaps a method weil_polynomials
on ZZ[x]
and QQ[x]
that returns your iterator?
Also, if someone can point me to some guidance about a module to the Sage library (e.g., how to format
__init__.py
andall.py
and the like to make the new code discoverable), that would be helpful.
See http://doc.sagemath.org/html/en/developer/coding_basics.html#filesanddirectorystructure for some details. You'll also need to add lines to src/module_list.py
for each extension module.
comment:7 Changed 5 years ago by
Branch:  → u/kedlaya/exhaust_over_weil_polynomials 

comment:8 Changed 5 years ago by
Commit:  → d12b0ea0aa53cbf558e6ac873414778dd12796a4 

comment:9 Changed 3 years ago by
comment:10 Changed 3 years ago by
Branch:  u/kedlaya/exhaust_over_weil_polynomials 

Commit:  d12b0ea0aa53cbf558e6ac873414778dd12796a4 
comment:11 Changed 3 years ago by
Branch:  → u/kedlaya/weilpoly_search 

comment:12 Changed 3 years ago by
Commit:  → 2a62e66aa58ccd7e82740078ce2c71d62a10ea52 

comment:13 Changed 3 years ago by
does not work for me:
sage: from sage.rings.polynomial.weil.weil_polynomials import *  ImportError Traceback (most recent call last) <ipythoninput15b4f8184ba57> in <module>() > 1 from sage.rings.polynomial.weil.weil_polynomials import * ImportError: /home/chapoton/sage3/local/lib/python3.7/sitepackages/sage/rings/polynomial/weil/weil_polynomials.cpython37mx86_64linuxgnu.so: undefined symbol: GOMP_loop_nonmonotonic_dynamic_start
and there are missing empty lines in the doc after lines ending with ::
comment:14 Changed 3 years ago by
Milestone:  sage8.1 → sage9.1 

That is the code looking for OpenMP (which is optional, since we don't ship it with Sage). Does it help if you take out the compiler directive in line 2 of sage/rings/polynomial/weil/weil_polynomials.pyx
?
The docstrings need a fair bit of work to get to 100% doctest coverage, let alone proper formatting. I can of course work on that independently.
comment:16 Changed 3 years ago by
Commit:  2a62e66aa58ccd7e82740078ce2c71d62a10ea52 → 1438c238cc5ab5aca7b0f558ff0261f7112ca9ec 

comment:17 Changed 3 years ago by
Cc:  David Roe added 

In addition to suppressing OpenMP, I also added doctests to get to 100% coverage.
Cc'ing roed, who is somewhat familiar to the code.
comment:18 Changed 3 years ago by
please remove the "next" method.
and in the test of __next__
, use next(it) to call the iterator.
comment:19 Changed 3 years ago by
Commit:  1438c238cc5ab5aca7b0f558ff0261f7112ca9ec → 7516836408314c97f176d62d677b7d2d924e861b 

Branch pushed to git repo; I updated commit sha1. New commits:
7516836  Removed "next" method

comment:20 Changed 3 years ago by
Commit:  7516836408314c97f176d62d677b7d2d924e861b → 1a6feb9edc7b3621738f1dac42ea0dbeea7282c3 

Branch pushed to git repo; I updated commit sha1. New commits:
1a6feb9  Merge edits from Edgar Costa

comment:23 Changed 3 years ago by
Branch:  u/kedlaya/weilpoly_search → u/roed/weilpoly_search 

comment:24 Changed 3 years ago by
Commit:  1a6feb9edc7b3621738f1dac42ea0dbeea7282c3 → c1be1fbff4f97dcd107be3e92c6e3b676afdbf00 

About to board a flight, and I want to make a few more changes, but can you take a look at the documentation I added and make sure it looks right? It would also be nice to see some examples illustrating the different inputs available to the iterator.
New commits:
c1be1fb  Some Weil polynomial changes

comment:25 Changed 3 years ago by
Commit:  c1be1fbff4f97dcd107be3e92c6e3b676afdbf00 → d88c654e80d164044cfb3b946f2475ef6dd1ece2 

Branch pushed to git repo; I updated commit sha1. New commits:
d88c654  Fix some raise/return problems, add weil_polynomials method for polynomial rings, add some documentation

comment:26 followup: 30 Changed 3 years ago by
Alright, I made the other changes I wanted to make (most notably adding a method to polynomial rings). Here are some documentation questions that I'd like to see addressed, but I think this ticket is basically ready to go.
 I don't understand how specifying congruence constraints on leading coefficients works. I tried the following:
sage: R.<T> = ZZ[] sage: R.weil_polynomials(4,2,lead=((1,0),(0,2))) [T^4 + 4, T^4  T^2 + 4, T^4  2*T^2 + 4, T^4  3*T^2 + 4, T^4  4*T^2 + 4]
I would expect this to give polynomials where the coefficient of T^3
was even, but I'm not sure what I'm getting. Is it ignoring the 2 and giving me those where the coefficient of T^3
is exactly 0? Kiran, can you give me an idea of how this functionality is supposed to work?
 I don't quite understand what
node_limit
does. Raises aRuntimeError
if the number of terminal nodes ever exceeds the given value?  Similarly, I guessed that
squarefree
omits polynomials that are not squarefree.
Overall, can you check/correct the changes I made? Also, if there's anything else useful to be said about how to recompile with OpenMP support, feel free to augment the documentation that I added.
comment:27 Changed 3 years ago by
Branch:  u/roed/weilpoly_search → u/kedlaya/weilpoly_search 

comment:28 Changed 3 years ago by
Commit:  d88c654e80d164044cfb3b946f2475ef6dd1ece2 → 0aaec041320d09285a7d95171147d32f4304e850 

Branch pushed to git repo; I updated commit sha1. New commits:
0aaec04  Updated some docstrings

comment:29 Changed 3 years ago by
Commit:  0aaec041320d09285a7d95171147d32f4304e850 → 6f48bf4e43e3afd232f719a760fb877c97951853 

Branch pushed to git repo; I updated commit sha1. New commits:
6f48bf4  Fix squarefree search, add doctest

comment:30 Changed 3 years ago by
Authors:  → Kiran Kedlaya 

Status:  new → needs_review 
Replying to roed:
Alright, I made the other changes I wanted to make (most notably adding a method to polynomial rings). Here are some documentation questions that I'd like to see addressed, but I think this ticket is basically ready to go.
I made a few tweaks in the latest commits. I really like having a method for polynomial rings; I'm guessing most users will only use the code this way. The iterator is really only needed for power use cases.
Since there is already an is_weil_polynomial
method for polynomial elements, I edited the docstring for that method to point to weil_polynomials
and vice versa.
 I don't understand how specifying congruence constraints on leading coefficients works. I tried the following:
sage: R.<T> = ZZ[] sage: R.weil_polynomials(4,2,lead=((1,0),(0,2))) [T^4 + 4, T^4  T^2 + 4, T^4  2*T^2 + 4, T^4  3*T^2 + 4, T^4  4*T^2 + 4]I would expect this to give polynomials where the coefficient of
T^3
was even, but I'm not sure what I'm getting. Is it ignoring the 2 and giving me those where the coefficient ofT^3
is exactly 0? Kiran, can you give me an idea of how this functionality is supposed to work?
You just caught a bug in the C code which I have now fixed (here and upstream). I added a doctest documenting how this is supposed to work.
 I don't quite understand what
node_limit
does. Raises aRuntimeError
if the number of terminal nodes ever exceeds the given value?
Correct. It is there as a failsafe in case you don't want your code to run forever.
 Similarly, I guessed that
squarefree
omits polynomials that are not squarefree.
Correct, except that there was a (longknown) bug in that too. I fixed that and added a doctest.
Overall, can you check/correct the changes I made? Also, if there's anything else useful to be said about how to recompile with OpenMP support, feel free to augment the documentation that I added.
One issue is that on my system, I have to put the distutils lines at the top of the code when uncommenting them, which I think runs contrary to Sage conventions. I added a comment about this.
Since it seems we are basically into the review phase anyway, let me go ahead and set state accordingly. I would be particularly open to suggestions for additional doctests; there are probably many use cases I haven't thought to test yet, and I'd like to make sure not to break those in future versions of the code.
comment:31 Changed 3 years ago by
Branch:  u/kedlaya/weilpoly_search → u/roed/weilpoly_search 

comment:32 Changed 3 years ago by
Commit:  6f48bf4e43e3afd232f719a760fb877c97951853 → d8a813f7df1d503ef41e16c28beb2f77907fe444 

Branch pushed to git repo; I updated commit sha1. New commits:
d8a813f  Add some weil polynomial tests

comment:33 Changed 3 years ago by
Reviewers:  → David Roe 

I've added some more tests. I think I'm happy to give this positive review if all tests are passing. I'm also happy to try to keep brainstorming some more doctests if you'd like.
comment:34 Changed 3 years ago by
Branch:  u/roed/weilpoly_search → u/kedlaya/weilpoly_search 

comment:35 Changed 3 years ago by
Commit:  d8a813f7df1d503ef41e16c28beb2f77907fe444 → dbb60955f2e17b0b73dbd0353f4f8bfed223916b 

Branch pushed to git repo; I updated commit sha1. New commits:
dbb6095  Fix compiler warnings

comment:36 Changed 3 years ago by
Commit:  dbb60955f2e17b0b73dbd0353f4f8bfed223916b → e0b9ff9bcd8d3b5ef3f1c6b40fd6e6f6a1c175a9 

Branch pushed to git repo; I updated commit sha1. New commits:
e0b9ff9  Add ref to github repo for Weil polynomials

comment:37 Changed 3 years ago by
A few lastminute changes:
 There was a trivial bug in
polynomial_ring.py
about checking the base ring (which patchbot also noticed); I fixed that and added some doctests to confirm.  I fixed some compiler warnings on the backend.
 I added a link to the github repo in the main package docstring.
That's probably enough doctests for the moment; I'll inevitably have to add more in response to later bugfixes. Let's see what patchbot has to say next.
comment:38 Changed 3 years ago by
Milestone:  sage9.1 → sage9.0 

Status:  needs_review → positive_review 
Patchbot is green; I think we're good to go! I'll optimistically set the milestone to 9.0. :)
comment:39 followup: 42 Changed 3 years ago by
On Python 2 there are various errors of the form
********************************************************************** File "src/sage/rings/polynomial/weil/weil_polynomials.pyx", line 168, in sage.rings.polynomial.weil.weil_polynomials.dfs_manager.node_count Failed example: _ = next(it) Exception raised: Traceback (most recent call last): File "/var/lib/buildbot/slave/sage2_git/build/local/lib/python2.7/sitepackages/sage/doctest/forker.py", line 681, in _run self.compile_and_execute(example, compiler, test.globs) File "/var/lib/buildbot/slave/sage2_git/build/local/lib/python2.7/sitepackages/sage/doctest/forker.py", line 1123, in compile_and_execute exec(compiled, globs) File "<doctest sage.rings.polynomial.weil.weil_polynomials.dfs_manager.node_count[3]>", line 1, in <module> _ = next(it) TypeError: instance has no next() method **********************************************************************
comment:40 Changed 3 years ago by
Status:  positive_review → needs_work 

comment:41 Changed 3 years ago by
Commit:  e0b9ff9bcd8d3b5ef3f1c6b40fd6e6f6a1c175a9 → 7f44a49a42de8291e091ca2f4c516111282888b0 

Branch pushed to git repo; I updated commit sha1. New commits:
7f44a49  Reinstate next() method for Py2 compatibility

comment:42 Changed 3 years ago by
Status:  needs_work → needs_review 

Replying to vbraun:
On Python 2 there are various errors of the form
********************************************************************** File "src/sage/rings/polynomial/weil/weil_polynomials.pyx", line 168, in sage.rings.polynomial.weil.weil_polynomials.dfs_manager.node_count Failed example: _ = next(it) Exception raised: Traceback (most recent call last): File "/var/lib/buildbot/slave/sage2_git/build/local/lib/python2.7/sitepackages/sage/doctest/forker.py", line 681, in _run self.compile_and_execute(example, compiler, test.globs) File "/var/lib/buildbot/slave/sage2_git/build/local/lib/python2.7/sitepackages/sage/doctest/forker.py", line 1123, in compile_and_execute exec(compiled, globs) File "<doctest sage.rings.polynomial.weil.weil_polynomials.dfs_manager.node_count[3]>", line 1, in <module> _ = next(it) TypeError: instance has no next() method **********************************************************************
I was asked to remove that method in chapoton, but anyway here it is again.
comment:43 Changed 3 years ago by
Commit:  7f44a49a42de8291e091ca2f4c516111282888b0 → 6a3e93d0c200fa3d381c7d6b6433134439e04b33 

Branch pushed to git repo; I updated commit sha1. New commits:
6a3e93d  Fix typos in doctest

comment:44 Changed 3 years ago by
Looking at the patchbot logs, it seems that at least one of the bots failed to build because of nested function declarations in the C code. I thought we were always compiling the Sage library with gcc, which supports nested functions even though they are not in the ANSI standard...?
comment:46 Changed 3 years ago by
Commit:  6a3e93d0c200fa3d381c7d6b6433134439e04b33 → e02ae3cfc9bd4da34ee8f3b3b9a9b94e7666fa6f 

Branch pushed to git repo; I updated commit sha1. New commits:
e02ae3c  Unnest functions in C code for nonGNU compilers

comment:47 Changed 3 years ago by
Ah, it seems clang does not (yet) support nested functions as in GNU C. So I redid that bit of the C code; let's see what the patchbots have to say now.
comment:48 Changed 3 years ago by
Some of the patchbots are set up strangely, but I'm not seeing any systemic issues with this branch.
comment:49 Changed 3 years ago by
Milestone:  sage9.0 → sage9.1 

Status:  needs_review → positive_review 
I agree. We have successful tests run on Darwin, so I'm setting this back to positive review.
comment:50 Changed 3 years ago by
Branch:  u/kedlaya/weilpoly_search → e02ae3cfc9bd4da34ee8f3b3b9a9b94e7666fa6f 

Resolution:  → fixed 
Status:  positive_review → closed 
Status update: I've pushed many recent changes to the branch
repackage_for_sage
of the Github repo. In particular, I have been working to make the call syntax much more transparent; for instance, to compute the Weil polynomials corresponding to abelian varieties of dimensiong
over the finite field of orderq
, one can now use standard Python iterator syntax:Some todo items: check that all my old test scripts still work; write more tests; add more documentation; add more input sanitization.
In the meantime, I'd appreciate some feedback about where this might belong in Sage.