Comment #6 on issue 835 by [email protected]: limit((5**x+3**x)**(1/x), x,
oo) TODO
http://code.google.com/p/sympy/issues/detail?id=835
in pull/61 this sort of expression generates the following:
h[4] >>> log(1/x + (1/x)**log(4)).nseries(x, 0, 3)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "sympy\core\expr.py", line 875, in nseries
return self._eval_nseries(x, n, taylor)
File "sympy\functions\elementary\exponential.py", line 452, in
_eval_nseries
obj = ln(lt) + ln(a)._eval_nseries(x, n)
File "sympy\functions\elementary\exponential.py", line 475, in
_eval_nseries
assert n>=0,`n`
AssertionError: -5
The OP expression generates an infinite recursion that ends like this:
...
File "sympy\core\power.py", line 715, in _eval_nseries
nseries(x, n=n-e, taylor=taylor)).expand() +
File "sympy\core\expr.py", line 875, in nseries
return self._eval_nseries(x, n, taylor)
File "sympy\core\power.py", line 715, in _eval_nseries
nseries(x, n=n-e, taylor=taylor)).expand() +
File "sympy\core\expr.py", line 875, in nseries
return self._eval_nseries(x, n, taylor)
File "sympy\core\power.py", line 704, in _eval_nseries
b0 = b.limit(x,0)
File "sympy\core\expr.py", line 889, in limit
return limit(self, x, xlim, dir)
File "sympy\series\limits.py", line 157, in limit
return Add(*finite) + limit(Add(*unbounded), z, z0, dir)
File "sympy\series\limits.py", line 166, in limit
r = gruntz(e, z, z0, dir)
File "sympy\series\gruntz.py", line 444, in gruntz
return limitinf(e0, x)
File "sympy\series\gruntz.py", line 343, in limitinf
c0, e0 = mrv_leadterm(e,x)
File "sympy\series\gruntz.py", line 399, in mrv_leadterm
e_up = moveup([e],x)[0]
File "sympy\series\gruntz.py", line 356, in moveup
return [e.subs(x,exp(x)) for e in l]
File "sympy\core\basic.py", line 705, in subs
return self._subs_old_new(old, new)
File "sympy\core\cache.py", line 85, in wrapper
func_cache_it_cache[k] = r = func(*args, **kw_args)
File "sympy\core\basic.py", line 714, in _subs_old_new
return self._eval_subs(old, new)
File "sympy\core\mul.py", line 936, in _eval_subs
Mul(*comms_final)._eval_subs(old,new))#*[c._eval_subs(old,new) for
c in comm
s_final])
File "sympy\core\power.py", line 215, in _eval_subs
b, e = self.base._eval_subs(old, new), self.exp._eval_subs(old, new)
File "sympy\core\power.py", line 218, in _eval_subs
return Pow(b, e)
File "sympy\core\cache.py", line 85, in wrapper
func_cache_it_cache[k] = r = func(*args, **kw_args)
File "sympy\core\power.py", line 83, in __new__
obj = b._eval_power(e)
File "sympy\functions\elementary\exponential.py", line 190, in
_eval_power
return exp(b.args[0] * e)
File "sympy\core\multidimensional.py", line 136, in wrapper
return f(*args, **kwargs)
File "sympy\core\cache.py", line 85, in wrapper
func_cache_it_cache[k] = r = func(*args, **kw_args)
File "sympy\core\function.py", line 214, in __new__
return Application.__new__(cls, *args, **options)
File "sympy\core\multidimensional.py", line 136, in wrapper
return f(*args, **kwargs)
File "sympy\core\cache.py", line 85, in wrapper
func_cache_it_cache[k] = r = func(*args, **kw_args)
File "sympy\core\function.py", line 112, in __new__
evaluated = cls.eval(*args)
File "sympy\functions\elementary\exponential.py", line 40, in eval
coeff = arg.as_coefficient(S.Pi*S.ImaginaryUnit)
File "sympy\core\expr.py", line 317, in as_coefficient
coeff = self.match(w * expr)
File "sympy\core\basic.py", line 996, in match
return pattern.matches(self, {})
File "sympy\core\mul.py", line 562, in matches
return AssocOp._matches_commutative(self, expr, repl_dict, evaluate)
File "sympy\core\operations.py", line 173, in _matches_commutative
newexpr = self.__class__._combine_inverse(expr,
self.__class__(*exact_part))
File "sympy\core\mul.py", line 646, in _combine_inverse
return Mul(*a)/Mul(*b)
File "sympy\core\decorators.py", line 49, in __sympifyit_wrapper
return func(a, sympify(b, strict=True))
File "sympy\core\decorators.py", line 89, in binary_op_wrapper
return func(self, other)
File "sympy\core\expr.py", line 78, in __div__
return Mul(self, Pow(other, S.NegativeOne))
File "sympy\core\cache.py", line 85, in wrapper
func_cache_it_cache[k] = r = func(*args, **kw_args)
File "sympy\core\operations.py", line 39, in __new__
c_part, nc_part, order_symbols = cls.flatten(map(_sympify, args))
File "sympy\core\mul.py", line 298, in flatten
c_part.sort(Basic.compare)
File "sympy\core\basic.py", line 240, in compare
c = cmp(self.__class__, other.__class__)
File "sympy\core\core.py", line 258, in __gt__
if cls.__cmp__(other)==1:
File "sympy\core\core.py", line 228, in __cmp__
if not isinstance(other, BasicType):
RuntimeError: maximum recursion depth exceeded while calling a Python
object
h[4] >>>
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