On Feb 22, 2011, at 10:52 AM, Chris Smith wrote:

> andyl wrote:
>> Hi
>> 
>> I have been trying out sympy, working through the examples in the
>> documentation.  All went well, and was impressive, until I tried to
>> factor polynomials.  The example in the documentation was
>> 
>> f = 4*x**4 + 8*x**3 + 77*x**2 + 18*x + 153
>> 
>> and factor(f) gave  (9 + 4*x**2)*(17 + 2*x + x**2)  as expected.
>> 
>> But then factor(f, gaussian=True) or factor(f, extension=I) should
>> give according the documentation:
>> 
>> 4*(x - 3*I/2)*(x + 3*I/2)*(x - 4*I + 1)*(x + 4*I + 1)
>> 
>> Instead I get the same result as before, ie (9 + 4*x**2)*(17 + 2*x +
>> x**2)
>> 
> 
> Make sure you use the flag gaussian=True not gaussian=1 (at least in the new 
> polys12 branch) since it's picky in that regard.
> 

This should be fixed.

Aaron Meurer

> All in polys12:
> 
>    h[2] >>> f = 4*x**4 + 8*x**3 + 77*x**2 + 18*x + 153
>    h[2] >>> factor(f)
>    (9 + 4*x**2)*(17 + 2*x + x**2)
>    h[3] >>> factor(f,gaussian=1)
>    (9 + 4*x**2)*(17 + 2*x + x**2)
>    h[3] >>> factor(f,gaussian=True)
>    4*(x - 3*I/2)*(x + 3*I/2)*(1 + x - 4*I)*(1 + x + 4*I)
>    h[4] >>> factor(f,extension=I)
>    4*(x - 3*I/2)*(x + 3*I/2)*(1 + x - 4*I)*(1 + x + 4*I)
>    h[4] >>> factor(6*x-10)
>    2*(-5 + 3*x)
> 
> /c

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