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Additional functionality for Farey symbols #15265

Closed monien closed 10 years ago

monien commented 11 years ago

The additional functionality included in this patch are:

Added tests for LLT algorithm and reduction to cusp.

CC: @vbraun @loefflerd

Component: modular forms

Keywords: Farey symbol, arithmetic subgroups

Author: Hartmut Monien

Branch/Commit: u/mraum/ticket/15265 @ f24bf98

Reviewer: David Loeffler, Martin Raum

Issue created by migration from https://trac.sagemath.org/ticket/15265

monien commented 11 years ago

Description changed:

--- 
+++ 
@@ -6,5 +6,4 @@
 - reduction to cusp
 - identify cusp class

-There are a number of special cases where the straightforward implementation of the LLT algorithm fails. 
-More testing is required.
+Added tests for LLT algorithm and reduction to cusp.
11d1fc49-71a1-44e1-869f-76be013245a0 commented 11 years ago
comment:3

Pedantic comments: you need a proper commit message on the patch, or the release manager will complain; and there is a failing doctest in the `latex` method in congroup_gamma.py (typo?). I'm running a more thorough doctest cycle now.

11d1fc49-71a1-44e1-869f-76be013245a0 commented 11 years ago

Reviewer: David Loeffler

11d1fc49-71a1-44e1-869f-76be013245a0 commented 11 years ago
comment:4

OK, here's something a bit more important. The LaTeX display for Farey symbols doesn't work in the notebook: instead of rendering the Farey symbol it prints a little box with the raw LaTeX code in it. The problem is that the notebook uses MathJax for its latex rendering, and xypic is not supported by MathJax. I did warn you about this some while back.

Other than that the new code looks fine.

11d1fc49-71a1-44e1-869f-76be013245a0 commented 11 years ago

Work Issues: LaTeX display doesn't work

monien commented 11 years ago
comment:5

I do understand that the notebook (mathjax) currently does not support xymatrix. There are some attempts to make xymatrix also work for mathjax which would cure this problem. For the time being the situation is not very different from the one for using tikz with graphs. So the usual story: 

latex.add_to_preamble('\usepackage[all]{xy}')
latex.mathjax_avoid_list('xymatrix').

Then 

view(FareySymbol(Gamma0(23)), engine='pdflatex', tightpage=True)

does produce a latex view of the Farey symbol. I would hope that xymatrix would be included in in mathjax sooner than later. Please have a look at http://sonoisa.github.io/xyjax/xyjax.html. One could of course check wether the latex is produced in a notebook or not but that might lead to inconsistencies for the user.

I'll fix the (minor) problems tomorrow. Thanks for the prompt review.

monien commented 11 years ago
comment:6
11d1fc49-71a1-44e1-869f-76be013245a0 commented 11 years ago
comment:7

I'm not sure that the comparison with using tikz for graphs is a fair one. There's clearly no hope of getting standard LaTeX to render graphs, so it's reasonable to require an extra package. On the other hand, one can produce a viable approximation to a Farey symbol without using any extra packages, as in my recent ticket #14971; this may not look quite so nice as your version, but it avoids these compatibility issues.

Can you add a doctest illustrating your changes to arithgroup_element.acton?

monien commented 11 years ago
comment:8

I have added two doctests to arithgroup_element.acton. I do understand your concern about the latex. The question here is: Is the graph for the Farey symbol just some equation or a graph. I would opt for the latter.

I have modified the _latex_ of the Farey symbol so that it does work with sagemath cloud. To illustrate that it is fairly easy to use the current version of the latex output (one thing which has been bugging me for a long time is the extra brackets in the latex output in a sage worksheet) I included two examples how to use it.

The only other alternative I see is to add yet another property to the Farey symbol like graph() or the like to keep the nice latex format.

monien commented 11 years ago

latex as would produced by my new latex version

monien commented 11 years ago

Attachment: test latex for Farey symbols.tiff.gz

use in sage worksheet

monien commented 11 years ago

Attachment: test new Farey symbols -- Sage.pdf.gz

Attachment: farey.patch.gz

Farey symbol enhancement

vbraun commented 10 years ago
comment:9

Just so that I understand correctly, there are two potential LaTeX outputs, one with (here) and one without xy (at #14971)? How about you do

   if 'xymatrix' in latex.mathjax_avoid_list():
       output_with_xy()
   else:
       output_without_xy()

Since xy is in the default latex preamble we should probably add it to the avoid list by default, but that would be for another ticket...

monien commented 10 years ago

Branch: u/hmonien/ticket/15265

monien commented 10 years ago
comment:11

Added modified version of David's latex for FareySymbol.

7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

Commit: 119c796

7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

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

119c796Version with modified latex for FareySymbol.
18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:13

We did some parallel work. Hope it's ok for you to base the review on my branch (to which I already made some small changes).

New commits:

9da738atrac 15265: improvements for FareySymbol.
119c796Version with modified latex for FareySymbol.
18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:14

Another try to change the attached commit.

New commits:

9da738atrac 15265: improvements for FareySymbol.
119c796Version with modified latex for FareySymbol.
18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago

Changed commit from 119c796 to 52108f0

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago

Changed branch from u/hmonien/ticket/15265 to u/mraum/ticket/15265

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:15

Sorry for that, I'm not yet used to the new Trac system. I'm now changing the branch.

7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

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

248d2bctrac 15265: Add some further examples and one test to `_acton_` of elements of arithmetic groups.
961251atrac 15265: Minor changes to farey.cpp and farey.hpp.
d82a0b6trac 15265: Minor changes to sl2z.cpp and sl2z.hpp.
7d78f7ctrac 15265: Minor changes to farey_symbol.pyx
7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

Changed commit from 52108f0 to 7d78f7c

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago

Changed reviewer from David Loeffler to David Loeffler, Martin Raum

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:17

Hartmut, could you review the few changes that I made to your code? I have the following questions/comments, which you could help me with:

reference for rademacher_matrix in farey.cpp? farey.cpp:FareySymbol(istream& is) why not "is >> *this" ? farey.cpp:370 : it seems that x will always have length 1. farey.cpp:129 I understand this is tempting, but PRETTY_FUNCTION is gcc only. farey_symbol.pyx:plot rgbcolor option does not apply to Dedekind tesselation. Add one example each

I still need to test the code, but hopefully I'll have time for this tomorrow.

7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

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

be4148atrac 15265: Additional change to farey.cpp.
7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

Changed commit from 7d78f7c to be4148a

monien commented 10 years ago
comment:19

Martin,

all the changes seem to be okay. I think there was one more test for odd and even groups which try to remember ... .

7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

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

f24bf98trac 15265: various changes, finishing review.
7ed8c4ca-6d56-4ae9-953a-41e42b4ed313 commented 10 years ago

Changed commit from be4148a to f24bf98

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:21

Ok, I made all necessary changes. Can you have a look?

Just one, last question: Why do you actually use extern "C"? farey_symbols.pyx is translated to a C++ file, so that shouldn't be necessary.

monien commented 10 years ago
comment:22

This was added by somebody - not me - in some previous version of SAGE to have it working on some particular machine. Otherwise everything looks fine now.

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago

Changed work issues from LaTeX display doesn't work to none

18d65770-dc1e-4813-89a9-4828e4aae4a9 commented 10 years ago
comment:23

It's not wrong, and so let's keep it so that we don't break any architecture.

vbraun commented 10 years ago
comment:25

See #15719 for a documentation issue