Asking Sage to compute the cardinality of point sets of projective varieties over finite fields produces an infinite recursion error. This is weird, since the count_points() function works just fine (albeit slowly) in this situation.
Here's an example. Entering: F = FiniteField(37) P3.<x,y,z,w> = ProjectiveSpace(3,F) P3.point_set().cardinality() yields an error that begins: Error in lines 3-3 Traceback (most recent call last): File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/smc_sagews/sage_server.py", line 976, in execute exec compile(block+'\n', '', 'single') in namespace, locals File "", line 1, in <module> File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in cardinality return sum(ZZ.one() for point in self) File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in <genexpr> return sum(ZZ.one() for point in self) File "sage/structure/parent.pyx", line 1596, in sage.structure.parent.Parent.__getitem__ (/projects/sage/sage-7.3/src/build/cythonized/sage/structure/parent.c:12913) return self.list()[n] File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 602, in list return tuple(self) File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in cardinality return sum(ZZ.one() for point in self) File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in <genexpr> return sum(ZZ.one() for point in self) File "sage/structure/parent.pyx", line 1596, in sage.structure.parent.Parent.__getitem__ (/projects/sage/sage-7.3/src/build/cythonized/sage/structure/parent.c:12913) return self.list()[n] continues looping for a while, and ends: File "sage/structure/parent.pyx", line 1596, in sage.structure.parent.Parent.__getitem__ (/projects/sage/sage-7.3/src/build/cythonized/sage/structure/parent.c:12913) return self.list()[n] File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 602, in list return tuple(self) File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in cardinality return sum(ZZ.one() for point in self) File "/projects/sage/sage-7.3/local/lib/python2.7/site-packages/sage/schemes/generic/homset.py", line 584, in <genexpr> return sum(ZZ.one() for point in self) File "sage/structure/parent.pyx", line 1590, in sage.structure.parent.Parent.__getitem__ (/projects/sage/sage-7.3/src/build/cythonized/sage/structure/parent.c:12742) meth = getattr_from_other_class(self, self._category.parent_class, '__getitem__') File "sage/structure/misc.pyx", line 250, in sage.structure.misc.getattr_from_other_class (/projects/sage/sage-7.3/src/build/cythonized/sage/structure/misc.c:1731) if isinstance(self, cls): RuntimeError: maximum recursion depth exceeded while calling a Python object On the other hand, P3.count_points(1) returns [52060]. --Ursula. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
