Status: Accepted
Owner: matt...@gmail.com
Labels: Type-Defect Priority-Medium Integration
New issue 2718 by matt...@gmail.com: integrate() fails with
UnificationFailed
http://code.google.com/p/sympy/issues/detail?id=2718
In [4]: var('a:c,x', real=True)
Out[4]: (a, b, c, x)
In [5]: integrate(a/(a**2+b*a+b*c*x**2),x)
---------------------------------------------------------------------------
UnificationFailed Traceback (most recent call last)
/home/mateusz/repo/git/sympy/<ipython-input-5-96f555343d1c> in <module>()
----> 1 integrate(a/(a**2+b*a+b*c*x**2),x)
/home/mateusz/repo/git/sympy/sympy/utilities/decorator.py 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/mateusz/repo/git/sympy/sympy/integrals/integrals.py in
integrate(*args, **kwargs)
845
846 if isinstance(integral, Integral):
--> 847 return integral.doit(deep = False)
848 else:
849 return integral
/home/mateusz/repo/git/sympy/sympy/integrals/integrals.py in doit(self,
**hints)
362 continue
363
--> 364 antideriv = self._eval_integral(function, xab[0])
365
366 if antideriv is None:
/home/mateusz/repo/git/sympy/sympy/integrals/integrals.py in
_eval_integral(self, f, x)
575 # poly(x)
576 if g.is_rational_function(x):
--> 577 parts.append(coeff * ratint(g, x))
578 continue
579
/home/mateusz/repo/git/sympy/sympy/integrals/rationaltools.py in ratint(f,
x, **flags)
86 else:
87 for h, q in L:
---> 88 R = log_to_real(h, q, x, t)
89
90 if R is not None:
/home/mateusz/repo/git/sympy/sympy/integrals/rationaltools.py in
log_to_real(h, q, x, t)
252 R_u = roots(R, filter='R')
253
--> 254 if len(R_u) != R.count_roots():
255 return None
256
/home/mateusz/repo/git/sympy/sympy/polys/polytools.py in count_roots(f,
inf, sup)
2854 if inf_real and sup_real:
2855 if hasattr(f.rep, 'count_real_roots'):
-> 2856 count = f.rep.count_real_roots(inf=inf, sup=sup)
2857 else: # pragma: no cover
2858 raise OperationNotSupported(f, 'count_real_roots')
/home/mateusz/repo/git/sympy/sympy/polys/polyclasses.py in
count_real_roots(f, inf, sup)
755 def count_real_roots(f, inf=None, sup=None):
756 """Return the number of real roots of ``f`` in ``[inf,
sup]``. """
--> 757 return dup_count_real_roots(f.rep, f.dom, inf=inf, sup=sup)
758
759 def count_complex_roots(f, inf=None, sup=None):
/home/mateusz/repo/git/sympy/sympy/polys/rootisolation.py in
dup_count_real_roots(f, K, inf, sup)
652
653 if inf is None:
--> 654 signs_inf = dup_sign_variations([ dup_LC(s,
K)*(-1)**dup_degree(s) for s in sturm ], K)
655 else:
656 signs_inf = dup_sign_variations([ dup_eval(s, inf, K) for s
in sturm ], K)
/home/mateusz/repo/git/sympy/sympy/polys/densetools.py in
dup_sign_variations(f, K)
1124
1125 for coeff in f:
-> 1126 if coeff*prev < 0:
1127 k += 1
1128
/home/mateusz/repo/git/sympy/sympy/polys/polyclasses.py in __lt__(f, g)
1301
1302 def __lt__(f, g):
-> 1303 _, _, _, F, G = f.frac_unify(g)
1304 return F.__lt__(G)
1305
/home/mateusz/repo/git/sympy/sympy/polys/polyclasses.py in frac_unify(f, g)
1051 """Unify representations of two multivariate fractions. """
1052 if not isinstance(g, DMF) or f.lev != g.lev:
-> 1053 raise UnificationFailed("can't unify %s with %s" % (f,
g))
1054
1055 if f.dom == g.dom:
UnificationFailed: can't unify DMF(([[[]]], [[[mpz(1)]]]), ZZ) with 0
Note that this works when real=True isn't specified.
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