Re: [sympy] Bug with solve function
Thanks I think that this is a bug on roots_quintic. Can you open an issue on github: https://github.com/sympy/sympy/ On Mon, 20 Apr 2020 at 20:02, Tiam Koukpari wrote: > > I found a bug in Sympy's solve function. > > from sympy import solve > from sympy.abc import x > solve(x**5 - 6*x**3 - 6*x**2 + x - 6) > > I attached a .png of the error above. The same thing in Matlab returns > > >> syms x > >> eqn = x^5 - 6*x^3 - 6*x^2 - 6 == 0 > >> S = solve(eqn) > > S = > > root(z^5 - 6*z^3 - 6*z^2 - 6, z, 1) > root(z^5 - 6*z^3 - 6*z^2 - 6, z, 2) > root(z^5 - 6*z^3 - 6*z^2 - 6, z, 3) > root(z^5 - 6*z^3 - 6*z^2 - 6, z, 4) > root(z^5 - 6*z^3 - 6*z^2 - 6, z, 5) > > Thank you! > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sympy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/a34a0c26-b176-49a6-ba66-a8e69994b1e4%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAHVvXxQ9YwCO6chZLJ%3D98n_sHxSyxCosyuCg%2B_F%3DnoeD7H3FCg%40mail.gmail.com.
[sympy] Bug with solve function
I was not able to reproduce your error. This is what I get instead print(sol) [CRootOf(x**5 - 6*x**3 - 6*x**2 - 6, 0), CRootOf(x**5 - 6*x**3 - 6*x**2 - 6, 1), CRootOf(x**5 - 6*x**3 - 6*x**2 - 6, 2), CRootOf(x**5 - 6*x**3 - 6*x**2 - 6, 3), CRootOf(x**5 - 6*x**3 - 6*x**2 - 6, 4)] -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/f4e57b73-71df-439f-8e73-0caac4ad21ca%40googlegroups.com.
Re: [sympy] Bug with solve
It looks like this is fixed in master. I bisected it to https://github.com/sympy/sympy/commit/9b1f3d7402538c587a00fa4df162208998727830. Aaron Meurer On Wed, May 20, 2015 at 12:46 AM, Arnaud Usciati rait...@gmail.com wrote: Right, I have sympy-0.7.6.win32. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/f0619d17-cdc0-47dd-858c-6a6415d212d3%40googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6JLdNQZjY0d6dXjFA7Yf9kg1pnj02hBp_LctipuLH_6Uw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
[sympy] Bug with solve
Hello,
I tried to find the roots of : 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 -
x**2 + x*sqrt(x**3 - x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1)
- 3*x**2.5 - 4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 -
3*x**5.5 - 1 = 0.
x = symbols('x', real=True)
f = Lambda(x, 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 - x**2 + x*sqrt(x**3
- x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1) - 3*x**2.5 -
4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 - 3*x**5.5 - 1)
Input : solve(f(x), x)
Output : [0.149910458676117, 0.865324593883105, 1.00,
1.24896947842683, 2.56371129870321, 3.02429035798029]
But only 0.149910458676117 and 1 are really roots :
f(0.865324593883105) = 0.735269457206734
f(1.24896947842683) = -4.09736628717860
f(2.56371129870321) = -509.709822051607
f(3.02429035798029) = -1361.51149028959
Arnaud,
Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:15:05) [MSC v.1600 32
bit (Intel)] on win32
--
You received this message because you are subscribed to the Google Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/ece1f69e-919b-4bde-ab31-9213adf06c35%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Bug with solve
Hi,
I have : Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:15:05) [MSC
v.1600 32 bit (Intel)] on win32
Le mardi 19 mai 2015 18:25:33 UTC+2, Aaron Meurer a écrit :
What version of SymPy is this? On master I get
In [1]: x = symbols('x', real=True)
In [2]: f = Lambda(x, 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 - x**2
+ x*sqrt(x**3 - x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1)
- 3*x**2.5 - 4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 -
3*x**5.5 - 1)
In [3]: solve(f(x), x)
Out[3]: [0.149910458676117, 1.0]
(note that it takes a while)
Aaron Meurer
On Tue, May 19, 2015 at 6:29 AM, Arnaud Usciati rai...@gmail.com
javascript: wrote:
Hello,
I tried to find the roots of : 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3
-
x**2 + x*sqrt(x**3 - x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 +
1) -
3*x**2.5 - 4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 -
3*x**5.5 -
1 = 0.
x = symbols('x', real=True)
f = Lambda(x, 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 - x**2 +
x*sqrt(x**3
- x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1) - 3*x**2.5 -
4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 - 3*x**5.5 - 1)
Input : solve(f(x), x)
Output : [0.149910458676117, 0.865324593883105, 1.00,
1.24896947842683, 2.56371129870321, 3.02429035798029]
But only 0.149910458676117 and 1 are really roots :
f(0.865324593883105) = 0.735269457206734
f(1.24896947842683) = -4.09736628717860
f(2.56371129870321) = -509.709822051607
f(3.02429035798029) = -1361.51149028959
Arnaud,
Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:15:05) [MSC v.1600 32
bit
(Intel)] on win32
--
You received this message because you are subscribed to the Google
Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send
an
email to sympy+un...@googlegroups.com javascript:.
To post to this group, send email to sy...@googlegroups.com
javascript:.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/ece1f69e-919b-4bde-ab31-9213adf06c35%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/b0503758-e6c6-4152-8bc4-c594526d4908%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Bug with solve
You gave Python version not sympy.__version__ -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/d05d4cdb-11d4-4474-8543-a76bcf4e0018%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Bug with solve
Right, I have sympy-0.7.6.win32. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/f0619d17-cdc0-47dd-858c-6a6415d212d3%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Bug with solve
What version of SymPy is this? On master I get
In [1]: x = symbols('x', real=True)
In [2]: f = Lambda(x, 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 - x**2
+ x*sqrt(x**3 - x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1)
- 3*x**2.5 - 4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 -
3*x**5.5 - 1)
In [3]: solve(f(x), x)
Out[3]: [0.149910458676117, 1.0]
(note that it takes a while)
Aaron Meurer
On Tue, May 19, 2015 at 6:29 AM, Arnaud Usciati rait...@gmail.com wrote:
Hello,
I tried to find the roots of : 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 -
x**2 + x*sqrt(x**3 - x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1) -
3*x**2.5 - 4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 - 3*x**5.5 -
1 = 0.
x = symbols('x', real=True)
f = Lambda(x, 2*sqrt(x)*sqrt(x**3 - x**2 + 1) + 2*x**3 - x**2 + x*sqrt(x**3
- x**2 + 1) + 2*x**1.5 + 2*x**2.5*sqrt(x**3 - x**2 + 1) - 3*x**2.5 -
4*x**3.5*sqrt(x**3 - x**2 + 1) - 2*x**3.5 + 5*x**4.5 - 3*x**5.5 - 1)
Input : solve(f(x), x)
Output : [0.149910458676117, 0.865324593883105, 1.00,
1.24896947842683, 2.56371129870321, 3.02429035798029]
But only 0.149910458676117 and 1 are really roots :
f(0.865324593883105) = 0.735269457206734
f(1.24896947842683) = -4.09736628717860
f(2.56371129870321) = -509.709822051607
f(3.02429035798029) = -1361.51149028959
Arnaud,
Python 3.4.2 (v3.4.2:ab2c023a9432, Oct 6 2014, 22:15:05) [MSC v.1600 32 bit
(Intel)] on win32
--
You received this message because you are subscribed to the Google Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send an
email to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/ece1f69e-919b-4bde-ab31-9213adf06c35%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/CAKgW%3D6K924%2BxJm25isfUaA%2BxhtH%3DdBcDyK5esyJKYEapK1siJg%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.
[sympy] Bug in solve including commutative and non-commutative symbols
The simplest example I could think if is:
a = symbols('a',commutative=True)
c = symbols('c', commutative=False)
solve(a-c,a)
[]
which returns an empty list. If both symbols have commutative=True or both
have commutative=False, the correct solution [c] is returned.
Is there anything I am doing wrong here ?
--
You received this message because you are subscribed to the Google Groups
sympy group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sympy/a7d9e447-d259-440d-a6b0-cc7bb6626429%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
