Py3: Fix dynamics.arithmetic_dynamics for python3

[vklein]

Fix dynamics.arithmetic_dynamics for python3. One failling doctest remains.

[vklein]

New commits:

​ccf846c

Trac 27779: Fix arithmetic_dynamics for py3

[chapoton]

some of the new lines must be tagged # long time too, as they depend on #long results

+            sage: lst, label = f.automorphism_group(return_functions=True, iso_type=True) # long time
+            sage: sorted(lst, key=str), label

[git]

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

​b04931f

Trac #27779: Add missing `# long time` flag

[vklein]

Thanks ! Missing tag added.

[chapoton]

maybe add # abs tol 1e-11 to the last failing doctest ?

[vklein]

It works. You mean values (x^4 - 2.86348722511320e-12*y^4 : 1.41421356237310*y^4) and (x^4 + 7.74491581978509e-13*y^4 : 1.41421356237310*y^4) are both valid results for this doctest ?

[chapoton]

I thought so, but maybe this is not so clear. We should cc the authors of that piece of code.

[vklein]

Git blame says it's from Ben Hutz but he is not listed in sage account list.

[git]

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

​d2ad260

Trac #27779: Add `# abs tol 1e-11` tag to doctest

[bhutz]

Perhaps a cleaner fix here would be to change the doctest to

g,m = f.reduced_form(smallest_coeffs=False); m

The matrix is it producing for the conjugation is always an integer matrix, but just working over RR to conjugate and then conjugate by the inverse is introducing numerical error, so the resulting function is not an exact match of the original. So, the error that is cropping up in the doctest actually has nothing to do with the functionality of .reduced_form(), rather it is just a consequence of conjugating over a numerical field.

You should probably do the same thing for the doctest immediately following as I would have expected the same kind of issue over CC.

[git]

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

​e26a443

Trac #27779: Test the matrix result only for ...

[vklein]

Ok it's done.
Thank you for your help Ben.

[chapoton]

Ça me parait correct.