Page for Galois group fails 34T82

[edgarcosta]

https://beta.lmfdb.org/GaloisGroup/34T82

and the www version fail:

Exception on /GaloisGroup/34T82 [GET]
Traceback (most recent call last):
  File "/home/sage/sage-9.7/local/var/lib/sage/venv-python3.10.5/lib/python3.10/site-packages/flask/app.py", line 2525, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sage/sage-9.7/local/var/lib/sage/venv-python3.10.5/lib/python3.10/site-packages/flask/app.py", line 1822, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sage/sage-9.7/local/var/lib/sage/venv-python3.10.5/lib/python3.10/site-packages/flask/app.py", line 1820, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sage/sage-9.7/local/var/lib/sage/venv-python3.10.5/lib/python3.10/site-packages/flask/app.py", line 1796, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/home/lmfdb/lmfdb-git-dev/lmfdb/galois_groups/main.py", line 82, in by_label
    return render_group_webpage({'label': label})
  File "/home/lmfdb/lmfdb-git-dev/lmfdb/galois_groups/main.py", line 335, in render_group_webpage
    data['malle_a'] = wgg.malle_a
  File "sage/misc/lazy_attribute.pyx", line 127, in sage.misc.lazy_attribute._lazy_attribute.__get__
    result = self.f(a)
  File "/home/lmfdb/lmfdb-git-dev/lmfdb/galois_groups/transitive_group.py", line 224, in malle_a
    ccs = self.conjclasses
  File "sage/misc/lazy_attribute.pyx", line 127, in sage.misc.lazy_attribute._lazy_attribute.__get__
    result = self.f(a)
  File "/home/lmfdb/lmfdb-git-dev/lmfdb/galois_groups/transitive_group.py", line 204, in conjclasses
    cc = [isom.Image(z) for z in cc1]
  File "/home/lmfdb/lmfdb-git-dev/lmfdb/galois_groups/transitive_group.py", line 204, in <listcomp>
    cc = [isom.Image(z) for z in cc1]
  File "sage/libs/gap/element.pyx", line 2675, in sage.libs.gap.element.GapElement_MethodProxy.__call__
    return GapElement_Function.__call__(self, * ([self.first_argument] + list(args)))
  File "sage/libs/gap/element.pyx", line 2523, in sage.libs.gap.element.GapElement_Function.__call__
    sig_on()
RuntimeError: Aborted
[2024-08-30 11:31:06 UTC] 500 error on URL https://beta.lmfdb.org/GaloisGroup/34T82 ()

[roed314]

@jwj61 I'm seeing this again in other cases (e.g. https://beta.lmfdb.org/GaloisGroup/42T8771). Maybe it's worth disabling the new Malle invariants for larger degrees.

[jwj61]

Looking at it. I tried removing the Malle constant from all cases, and the page still doesn't load. From the error message, it looks like it involves to isomorphism to the abstract group.

[roed314]

Got a different but related traceback (in the flasklog):

Exception on /GaloisGroup/34T18 [GET]
Traceback (most recent call last):
  File "/home/sage/sage-10.1/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 2073, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/sage/sage-10.1/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1519, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/sage/sage-10.1/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1517, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/sage/sage-10.1/local/var/lib/sage/venv-python3.10/lib/python3.10/site-packages/flask/app.py", line 1503, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/galois_groups/main.py", line 82, in by_label
    return render_group_webpage({'label': label})
  File "/home/lmfdb/lmfdb-git-web/lmfdb/galois_groups/main.py", line 265, in render_group_webpage
    data['cclasses'] = wgg.conjclasses
  File "sage/misc/lazy_attribute.pyx", line 127, in sage.misc.lazy_attribute._lazy_attribute.__get__
    result = self.f(a)
  File "/home/lmfdb/lmfdb-git-web/lmfdb/galois_groups/transitive_group.py", line 204, in conjclasses
    cc = [isom.Image(z) for z in cc1]
  File "/home/lmfdb/lmfdb-git-web/lmfdb/galois_groups/transitive_group.py", line 204, in <listcomp>
    cc = [isom.Image(z) for z in cc1]
  File "sage/libs/gap/element.pyx", line 2645, in sage.libs.gap.element.GapElement_MethodProxy.__call__
    return GapElement_Function.__call__(self, * ([self.first_argument] + list(args)))
  File "sage/libs/gap/element.pyx", line 2514, in sage.libs.gap.element.GapElement_Function.__call__
    sig_on()
sage.libs.gap.util.GAPError: Error, reached the pre-set memory limit
(change it with the -o command line option)
[2024-09-25 12:42:36 UTC] 500 error on URL https://www.lmfdb.org/GaloisGroup/34T18 ()

[jwj61]

I believe that the Malle constant is a stumbling block. It seems that just removing it on affected pages won't be enough -- those pages will still be initializing their conjugacy classes which keeps the page from loading.

Another approach could be to precompute conjugacy class data. We don't rely on on-the-fly computations very much anymore.

[jwj61]

In making a table of conjugacy class data (just group label, size, encoded representative), what should be the cutoff, as in, if a group has more than N conjugacy classes, then we don't compute them. Using N=2500, it will have a total of 277 million classes; N=1500 gives 181 million classes; N=1000 gives 115 millions; N=500 gives 49 million.