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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