I confirm the very same behavior on sage-8.2.beta0. Looking at the
trace, it is likely the g_pow from Pynac that has a problem. I opened
the following ticket
https://trac.sagemath.org/ticket/24418
Thanks for your report.
Vincent
On 22/12/2017 01:06, Nathan McNew wrote:
I recently installed Sage 8.1 from source on a server running RHEL. The
install seemed to go fine, and sage passes all of the tests that run from
sage --testall.
However I've run into a lot of strange errors trying to run some of my code
that worked fine on my (Linux Mint) desktop running Sage 7.5.1.
A lot of the errors seem tricky to pin down exactly (oddly my numerical
values differ slightly from those obtained on my desktop in a few cases),
but I finally isolated one specific example that causes sage to crash.
Attempting to numerically approximate the value of 2^(450232897/4888643760)
results in a runtime error, though it never says what the error is. I've
copied and pasted the entire error output below.
If I modify the fraction slightly, it executes fine.
On several other sage installations, the exact same command
N(2^(450232897/4888643760))
executes, giving the value 1.06591892580915.
sage: N(2^(450232897/4888643760))
---------------------------------------------------------------------------
RuntimeError Traceback (most recent call last)
<ipython-input-70-d6e5760546c2> in <module>()
----> 1 N(Integer(2)**(Integer(450232897)/Integer(4888643760)))
/opt/sage/lib/python2.7/site-packages/sage/misc/functional.pyc in
numerical_approx(x, prec, digits, algorithm)
1385 return numerical_approx_generic(x, prec)
1386 else:
-> 1387 return n(prec, algorithm=algorithm)
1388
1389 n = numerical_approx
/home/nmcnew-admin/sage/sage-8.1/src/sage/symbolic/expression.pyx in
sage.symbolic.expression.Expression.numerical_approx
(build/cythonized/sage/symbolic/expression.cpp:35771)()
5764
5765 s = DefiniteSumExpander(self)
-> 5766 cdef Expression x = self._parent(s())
5767 from sage.rings.real_mpfr import RealField
5768 R = RealField(prec)
/opt/sage/lib/python2.7/site-packages/sage/symbolic/expression_conversions.pyc
in __call__(self, ex)
216 div = self.get_fake_div(ex)
217 return self.arithmetic(div, div.operator())
--> 218 return self.arithmetic(ex, operator)
219 elif operator in relation_operators:
220 return self.relation(ex, operator)
/opt/sage/lib/python2.7/site-packages/sage/symbolic/expression_conversions.pyc
in arithmetic(self, ex, operator)
1931 True
1932 """
-> 1933 return reduce(operator, map(self, ex.operands()))
1934
1935 def composition(self, ex, operator):
/home/nmcnew-admin/sage/sage-8.1/src/sage/symbolic/expression.pyx in
sage.symbolic.expression.Expression.__pow__
(build/cythonized/sage/symbolic/expression.cpp:26259)()
3913 relational_operator(base._gobj))
3914 else:
-> 3915 x = g_pow(base._gobj, nexp._gobj)
3916 return new_Expression_from_GEx(base._parent, x)
3917 if BOTH_ARE_ELEMENT(cl):
RuntimeError:
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