Re: Mathematica integration Vs Sympy
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- Subject: [mg130563] Re: Mathematica integration Vs Sympy
- From: Alex Krasnov <akrasnov at eecs.berkeley.edu>
- Date: Sun, 21 Apr 2013 05:16:06 -0400 (EDT)
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Mathematica's Integrate implicitly assumes that parameters have generic
values. The result can be invalid for special values, in this case, a==1.
It appears that the same is true for SymPy's integrate, as u.subs({a:1})
demonstrates.
For other values, the Mathematica and SymPy results appear to differ by
a constant of integration. Both results are valid. This is a consequence
of different integration procedures and can occur even for the same
integral in different forms in Mathematica and presumably SymPy.
Alex
On Sat, 20 Apr 2013, Sergio R wrote:
> Hello all,
>
> Just for fun a put an integral I was doing via mathematica
> WolframAlpha
> [ http://www.wolframalpha.com/input/?i=Integrate[1%2F%28x*%281-a*%281-x%29%29%29%2Cx]
> ]
> into the online sympy [ http://live.sympy.org/ ] console
> the following:
>
> a = Symbol('a'); g = 1/(x*(1-a*(1-x))) ; u=simplify(integrate(g,x))
>
> Then, to display the result, at the sympy ">>>" prompt, type u
> and hit return.
>
> To my surprise, sympy seems to give the right result without any
> assumption, while mathematica's result seems to assume a>1, which is
> not specified. Also for this case (a>1) sympy gives an extra constant
> which is not present in the mathematica result.
>
> Is there a way to make mathematica to output a general result like
> sympy
> in this case?
>
> Sergio
>
- References:
- Mathematica integration Vs Sympy
- From: Sergio R <sergiorquestion@gmail.com>
- Mathematica integration Vs Sympy