Status: Accepted
Owner: ----
CC: [email protected]
Labels: Type-Defect Priority-Medium Integration
New issue 3152 by [email protected]: Integration of
(x**3)**(-Rational(1,3)) raises CoeffExpValueError
http://code.google.com/p/sympy/issues/detail?id=3152
The integration of (x**3)**(-Rational(1,3)) raises. Here it the trace
In [5]: integrate((x**3)**(-Rational(1,3)),x)
ERROR: An unexpected error occurred while tokenizing input
The following traceback may be corrupted or invalid
The error message is: ('EOF in multi-line statement', (19, 0))
---------------------------------------------------------------------------
_CoeffExpValueError Traceback (most recent call last)
/home/raoul/<ipython-input-5-f4a6bf22ba59> in <module>()
----> 1 integrate((x**3)**(-Rational(1,3)),x)
/home/raoul/python/sympy/utilities/decorator.pyc in threaded_func(expr,
*args, **kwargs)
23 func(expr.rhs, *args,
**kwargs))
24 else:
---> 25 return func(expr, *args, **kwargs)
26
27 return threaded_func
/home/raoul/python/sympy/integrals/integrals.pyc in integrate(*args,
**kwargs)
1096
1097 if isinstance(integral, Integral):
-> 1098 return integral.doit(deep = False, meijerg = meijerg, conds
= conds)
1099 else:
1100 return integral
/home/raoul/python/sympy/integrals/integrals.pyc in doit(self, **hints)
507 antideriv = None
508 else:
--> 509 antideriv = self._eval_integral(function, xab[0],
meijerg1)
510 if antideriv is None and meijerg1 is True:
511 ret = try_meijerg(function, xab)
/home/raoul/python/sympy/integrals/integrals.pyc in _eval_integral(self, f,
x, meijerg)
777 if meijerg is not False and h is None:
778 # rewrite using G functions
--> 779 h = meijerint_indefinite(g, x)
780 if h is not None:
781 parts.append(coeff * h)
/home/raoul/python/sympy/integrals/meijerint.pyc in meijerint_indefinite(f,
x)
1490 results = []
1491 for a in list(_find_splitting_points(f, x)) + [S(0)]:
-> 1492 res = _meijerint_indefinite_1(f.subs(x, x + a), x)
1493 if res is None:
1494 continue
/home/raoul/python/sympy/integrals/meijerint.pyc in
_meijerint_indefinite_1(f, x)
1504 _debug('Trying to compute the indefinite integral of',
f, 'wrt', x)
1505
-> 1506 gs = _rewrite1(f, x)
1507 if gs is None:
1508 # Note: the code that calls us will do expand() and try
again
/home/raoul/python/sympy/integrals/meijerint.pyc in _rewrite1(f, x,
recursive)
1446 """
1447 fac, po, g = _split_mul(f, x)
-> 1448 g = _rewrite_single(g, x, recursive)
1449 if g:
1450 return fac, po, g[0], g[1]
/home/raoul/python/sympy/core/cache.pyc in wrapper(*args, **kw_args)
89 except KeyError:
90 pass
---> 91 func_cache_it_cache[k] = r = func(*args, **kw_args)
92 return r
93 return wrapper
/home/raoul/python/sympy/integrals/meijerint.pyc in _rewrite_single(f, x,
recursive)
1357 for fac, g in terms:
1358 r1 =
_get_coeff_exp(unpolarify(fac.subs(subs).subs(z, x),
-> 1359
exponents_only=True), x)
1360 g = g.subs(subs).subs(z, x)
1361 # NOTE these substitutions can in principle
introduce oo,
/home/raoul/python/sympy/integrals/meijerint.pyc in _get_coeff_exp(expr, x)
286 return c, S(1)
287 else:
--> 288 raise _CoeffExpValueError('expr not of form a*x**b: %s' %
expr)
289
290 def _exponents(expr, x):
_CoeffExpValueError: expr not of form a*x**b: oo
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