On 16 Jan., 00:28, fabian.seo...@gmail.com wrote:
> From: Fabian Seoane <fab...@fseoane.net>
>
> Docstring of roots by Vinzent Steinberg.
> This has been discussed on issue #1158.
> ---
> sympy/polys/rootfinding.py | 10 +++++-----
> sympy/polys/tests/test_polynomial.py | 5 +++--
> 2 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/sympy/polys/rootfinding.py b/sympy/polys/rootfinding.py
> index bf604ed..f60dceb 100644
> --- a/sympy/polys/rootfinding.py
> +++ b/sympy/polys/rootfinding.py
> @@ -162,9 +162,9 @@ def roots(f, *symbols, **flags):
>
> Only roots expressible via radicals will be returned. To get
> a complete set of roots use RootOf class or numerical methods
> - instead. By default cubic and quartic formulas aren't used in
> - the algorithm because of unreadable output. To enable them
> - set cubics=True or quartics=True respectively.
> + instead. By default cubic and quartic formulas are used in
> + the algorithm. To disable them because of unreadable output
> + set cubics=False or quartics=False respectively.
>
> To get roots from a specific domain set the 'domain' flag with
> one of the following specifiers: Z, Q, R, I, C. By default all
> @@ -224,7 +224,7 @@ def roots(f, *symbols, **flags):
> elif n == 2:
> zeros += roots_quadratic(g)
> elif n == 3:
> - if flags.get('cubics', False):
> + if flags.get('cubics', True):
> # TODO: now we can used factor() not only
> # for cubic polynomials. See #1158
> try:
> @@ -238,7 +238,7 @@ def roots(f, *symbols, **flags):
> except PolynomialError:
> zeros += roots_cubic(g)
> elif n == 4:
> - if flags.get('quartics', False):
> + if flags.get('quartics', True):
> zeros += roots_quartic(g)
>
> return zeros
> diff --git a/sympy/polys/tests/test_polynomial.py
> b/sympy/polys/tests/test_polynomial.py
> index 3ea8643..1764626 100644
> --- a/sympy/polys/tests/test_polynomial.py
> +++ b/sympy/polys/tests/test_polynomial.py
> @@ -995,6 +995,7 @@ def test_roots():
> assert roots(1, x) == {}
> assert roots(x, x) == {S.Zero: 1}
> assert roots(x**9, x) == {S.Zero: 9}
> + assert roots(((x-2)*(x+3)*(x-4)).expand(), x) == {-Integer(3): 1,
> Integer(2): 1, Integer(4): 1}
>
> assert roots(2*x+1, x) == {-S.Half: 1}
> assert roots((2*x+1)**2, x) == {-S.Half: 2}
> @@ -1084,11 +1085,11 @@ def test_roots():
> S.Half + S.Half*y - S.Half*(1 - 2*y + y**2 + 8*x**2)**S.Half: 1,
> }
>
> - assert roots(x**3 + 2*x**2 + 4*x + 8, x) == {}
> + assert roots(x**3 + 2*x**2 + 4*x + 8, x) == {-Integer(2): 1, -2*I: 1,
> 2*I: 1}
> assert roots(x**3 + 2*x**2 + 4*x + 8, x, cubics=True) == \
> {-2*I: 1, 2*I: 1, -Integer(2): 1}
>
> - assert roots(a*b*c*x**3 + 2*x**2 + 4*x + 8, x) == {}
> + assert roots(a*b*c*x**3 + 2*x**2 + 4*x + 8, x, cubics=False) == {}
> assert roots(a*b*c*x**3 + 2*x**2 + 4*x + 8, x, cubics=True) != {}
>
> assert roots(x**4-1, x, domain='Z') == {S.One: 1, -S.One: 1}
> --
> 1.6.0.2
Thanks, I have no objections.
+1
Vinzent
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