Re: Issue 3560 in sympy: solve() is a giant mess

Sun, 17 Feb 2013 05:36:19 -0800 


Comment #13 on issue 3560 by [email protected]: solve() is a giant mess
http://code.google.com/p/sympy/issues/detail?id=3560
Here some (redundant) code picking up (again) some of the mess. The code is interpreted with Python 3.2.3 and Python 2.7.3. The version of sympy is given below. First I post the code and then the output within IDLE 

import sympy
print(sympy.__version__)
a = sympy.var('a')
x = sympy.Symbol('x')
ss = sympy.solve(x**5 - 5*x + 12)
print(ss)
print([ss[i].n() for i in range(5)])
ss = sympy.solve([x**5 - 5*x + 12], x)
print(ss)
ss = sympy.solve(a**5 - 5*a + 12, a)
print(ss)
print([ss[i].n() for i in range(5)])
ss = sympy.solve([a**5 - 5*a + 12])
print(ss)
ss = sympy.solve([a**4 - 5*a + 12])
print(ss)
ss = sympy.solve([x**4 - 5*x + 12], x)
print(ss)

OUTPUT Python3:
Python 3.2.3 (default, Oct 19 2012, 19:53:57)
[GCC 4.7.2] on linux2
Type "copyright", "credits" or "license()" for more information.
================================ RESTART ================================ 

0.7.2
[RootOf(x**5 - 5*x + 12, 0), RootOf(x**5 - 5*x + 12, 1), RootOf(x**5 - 5*x + 12, 2), RootOf(x**5 - 5*x + 12, 3), RootOf(x**5 - 5*x + 12, 4)] [-1.84208596619025, -1.84208596619025, -1.84208596619025, 1.2728972239225 - 0.719798681483861*I, 1.2728972239225 + 0.719798681483861*I] 
[]
[RootOf(a**5 - 5*a + 12, 0), RootOf(a**5 - 5*a + 12, 1), RootOf(a**5 - 5*a + 12, 2), RootOf(a**5 - 5*a + 12, 3), RootOf(a**5 - 5*a + 12, 4)] [-1.84208596619025, -1.84208596619025, -1.84208596619025, 1.2728972239225 - 0.719798681483861*I, 1.2728972239225 + 0.719798681483861*I] 
[]
[{a: -sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 + sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) - 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2}, {a: sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 - sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2}, {a: -sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) - 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 - sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2}, {a: sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 + sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2}] [(-sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 + sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) - 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2,), (sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 - sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2,), (-sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) - 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 - sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2,), (sqrt(-2*(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 10/sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3)) - 8/(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2 + sqrt(8/(25/16 + 3*sqrt(1751)*I/16)**(1/3) + 2*(25/16 + 3*sqrt(1751)*I/16)**(1/3))/2,)] 



NOW Python2
The (different) code:
import sympy
print(sympy.__version__)
a = sympy.var('a')
x = sympy.Symbol('x')
ss = sympy.solve(x**5 - 5*x + 12)
print(ss)
ss = sympy.solve([x**5 - 5*x + 12], x)
print(ss)
ss = sympy.solve(a**5 - 5*a + 12, a)
print(ss)
ss = sympy.solve([a**5 - 5*a + 12])
print(ss)
ss = sympy.solve([a**4 - 5*a + 12])
print(ss)
ss = sympy.solve([x**4 - 5*x + 12], x)
print(ss)

The output
Python 2.7.3 (default, Sep 26 2012, 21:53:58)
[GCC 4.7.2] on linux2
Type "copyright", "credits" or "license()" for more information.
================================ RESTART ================================ 

0.7.1.rc1
[]
[]
[]
[]
[((-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 + (8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), (-(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 + (-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) - 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), (-(-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) - 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 - (8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), ((8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 - (-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,)] [((-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 + (8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), (-(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 + (-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) - 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), (-(-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) - 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 - (8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,), ((8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2 - (-2*(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 10/(8/(25/16 + 3*1751**(1/2)*I/16)**(1/3) + 2*(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2) - 8/(25/16 + 3*1751**(1/2)*I/16)**(1/3))**(1/2)/2,)] 


You can of course reproduce this with your python(3) (idle(3)) installation.


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