Status: Accepted
Owner: ----
Labels: Type-Defect Priority-Medium Polynomial
New issue 2835 by [email protected]: PolynomialError with minpoly()
http://code.google.com/p/sympy/issues/detail?id=2835
I found this from the expression from issue 2834:
In [50]: [minpoly(i) for i in x.as_numer_denom()]
---------------------------------------------------------------------------
PolynomialError Traceback (most recent call last)
/Users/aaronmeurer/Documents/python/sympy/sympy/<ipython-input-50-ffbba6cffd4e>
in
<module>()
----> 1 [minpoly(i) for i in x.as_numer_denom()]
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/numberfields.pyc
in
minimal_polynomial(ex, x, **args)
130 else:
131 F = [x - bottom_up_scan(ex)] + mapping.values()
--> 132 G = groebner(F, symbols.values() + [x], order='lex')
133
134 _, factors = factor_list(G[-1])
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polytools.pyc
in groebner(F, *gens, **args)
5458
5459 """
-> 5460 return GroebnerBasis(F, *gens, **args)
5461
5462 def is_zero_dimensional(F, *gens, **args):
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polytools.pyc
in __new__(cls, F, *gens, **args)
5485
5486 try:
-> 5487 polys, opt = parallel_poly_from_expr(F, *gens, **args)
5488 except PolificationFailed, exc:
5489 raise ComputationFailed('groebner', len(F), exc)
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polytools.pyc
in parallel_poly_from_expr(exprs, *gens, **args)
3670 """Construct polynomials from expressions. """
3671 opt = options.build_options(gens, args)
-> 3672 return _parallel_poly_from_expr(exprs, opt)
3673
3674 def _parallel_poly_from_expr(exprs, opt):
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polytools.pyc
in _parallel_poly_from_expr(exprs, opt)
3721
3722 try:
-> 3723 reps, opt = _parallel_dict_from_expr(exprs, opt)
3724 except GeneratorsNeeded:
3725 raise PolificationFailed(opt, origs, exprs, True)
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polyutils.pyc
in _parallel_dict_from_expr(exprs, opt)
276
277 if opt.gens:
--> 278 reps, gens = _parallel_dict_from_expr_if_gens(exprs, opt)
279 else:
280 reps, gens = _parallel_dict_from_expr_no_gens(exprs, opt)
/Users/aaronmeurer/Documents/python/sympy/sympy/sympy/polys/polyutils.pyc
in _parallel_dict_from_expr_if_gens(exprs, opt)
161 coeff.append(factor)
162 else:
--> 163 raise PolynomialError("%s contains an
element of the generators set" % factor)
164
165 monom = tuple(monom)
PolynomialError: sqrt(_a4) contains an element of the generators set
In [83]: print x
(-240*sqrt(2)*sqrt(sqrt(5) + 5)*sqrt(8*sqrt(5) + 40) -
360*sqrt(2)*sqrt(-8*sqrt(5) + 40)*sqrt(-sqrt(5) + 5) -
120*sqrt(10)*sqrt(-8*sqrt(5) + 40)*sqrt(-sqrt(5) + 5) +
120*sqrt(2)*sqrt(-8*sqrt(5) + 40)*sqrt(sqrt(5) + 5) +
120*sqrt(2)*sqrt(-sqrt(5) + 5)*sqrt(8*sqrt(5) + 40) +
120*sqrt(10)*sqrt(-8*sqrt(5) + 40)*sqrt(sqrt(5) + 5) +
120*sqrt(10)*sqrt(-sqrt(5) + 5)*sqrt(8*sqrt(5) + 40))/(-36000 -
7200*sqrt(5) + (12*sqrt(10)*sqrt(sqrt(5) + 5) + 24*sqrt(10)*sqrt(-sqrt(5) +
5))**2)
The error also occurs if you just call minpoly(x).
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