inconsistent treatment of cosine zero
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Bill McLean
Oct 18, 2015, 11:32:27 PM10/18/15
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This behaviour seems strange. The case k=0 is handled correctly when integrating cos(k*x), but not cos(k*pi*x).
In [1]: integrate(cos(k*x),(x,0,pi))
Out[1]:
⎧π for k = 0
⎨
⎩0 otherwise
In [2]: integrate(cos(k*pi*x),(x,0,1))
Out[2]: 0
In [1]: integrate(cos(k*x),(x,0,pi))
Out[1]:
⎧π for k = 0
⎨
⎩0 otherwise
In [2]: integrate(cos(k*pi*x),(x,0,1))
Out[2]: 0
Aaron Meurer
Oct 19, 2015, 12:15:56 PM10/19/15
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For me they both give Piecewise results in SymPy 0.7.6.1.
Aaron Meurer
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Bill McLean
Oct 19, 2015, 8:53:42 PM10/19/15
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OK. I should have mentioned that I am running SymPy 0.7.4.1.
Aaron Meurer
Oct 19, 2015, 9:05:26 PM10/19/15
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Looks like it's a bug that's been fixed since then. I recommend
upgrading if you can.
For reference, integrate() uses several different integration
algorithms, so you can end up getting different looking results
depending on which algorithm ends up being used (even in the latest
version). I believe the latest version has the logic for splitting out
cases into Piecewise expressions applied to most if not all of the
algorithms, though.
Aaron Meurer
On Mon, Oct 19, 2015 at 7:33 PM, Bill McLean <naelc...@gmail.com> wrote:
> OK. I should have mentioned that I am running SymPy 0.7.4.1.
>
upgrading if you can.
For reference, integrate() uses several different integration
algorithms, so you can end up getting different looking results
depending on which algorithm ends up being used (even in the latest
version). I believe the latest version has the logic for splitting out
cases into Piecewise expressions applied to most if not all of the
algorithms, though.
Aaron Meurer
On Mon, Oct 19, 2015 at 7:33 PM, Bill McLean <naelc...@gmail.com> wrote:
> OK. I should have mentioned that I am running SymPy 0.7.4.1.
>
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