just noticed more problems with power series sum

97 views
Skip to first unread message

asciisi...@gmail.com

unread,
Aug 23, 2020, 10:49:34 PM8/23/20
to sympy
This again:

sympy.summation(sympy.S('z^k / k'), sympy.S('(k, 1, oo)'))
Piecewise((-log(1 - z), (z >= -1) & (z < 1)), (Sum(z**k/k, (k, 1, oo)), True))

I don't know what ">=" and mean "<", since Sympy (a program about math) was documented by a non-mathematician who neglected to define his mathematical terms; but it looks a lot like Sympy is singling out a segment of the real line instead of a disk in the complex plane. This program was designed from the ground up by amateurs not up to the task.

first last

unread,
Aug 24, 2020, 12:02:17 AM8/24/20
to sy...@googlegroups.com
There's a lot of literature about logic out there that no one who's designed a CAS has read. A good CAS would take no more work to make than the contemporary CAS's, which as a class are the worst made software I've ever used extensively in my fifty years. Euclid wrote a crystal clear manual 2,500 years ago, but you clowns couldn't manage it.

--
You received this message because you are subscribed to a topic in the Google Groups "sympy" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/sympy/28qmAIL3Xro/unsubscribe.
To unsubscribe from this group and all its topics, send an email to sympy+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/e5896cd0-adf1-4447-94df-0c75b63c209an%40googlegroups.com.

Aaron Meurer

unread,
Aug 24, 2020, 4:41:31 PM8/24/20
to sympy
Please keep discussions on this mailing list civil. Everyone who posts
on this list is expected to follow the SymPy code of conduct
https://github.com/sympy/sympy/blob/master/CODE_OF_CONDUCT.md.

Convergence conditions returned by summation() and integrate() are not
guaranteed to be tight. That is why the "otherwise" condition is the
unevaluated sum/integral. It is possible for values outside of the
given condition will still produce a convergent result.

Aaron Meurer
> 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.
> To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CABc8mQWU2mkO2wOe_vHDdUJ8jP2ZJ7s_Rg1fY5cVyXBV-VmUgA%40mail.gmail.com.

first last

unread,
Aug 24, 2020, 8:35:56 PM8/24/20
to sy...@googlegroups.com
I am sorry about the language. There is stress and fatigue on my end, some unrelated to Sympy, but also a lot due to CAS software and open-source software including Sympy. Sympy's documentation deficiencies have cost me months, and that's serious and I'm trying to make that point. I think releasing poorly documented software is uncivil. I think you were uncivil before I was. But, you're the mod, so I will be civil.



Oscar Benjamin

unread,
Aug 24, 2020, 8:55:10 PM8/24/20
to sympy
> I think you were uncivil before I was

Please try to avoid being personal. You don't know who contributed
what or when and it's not even useful to think who to "blame" when you
are looking at something created by volunteers in whatever limited
time they have available. I personally started working on sympy in a
significant way around 2 years ago. At that point sympy and its
documentation were mostly in a similar state to the way they are now.
In the time since I have tried to improve things and the same goes for
all of the contributors who have worked on sympy.

I agree that the documentation can be improved. Significant
improvements are planned and progress is being made but in some ways
it is still early days. After David pointed out that the assumptions
documentation is misleading I've been thinking about rewriting it. I
don't have time to do it immediately but I am probably best placed to
improve that particular part of the documentation so I will try to
find time at some point. Note though that David pointed that out
without any judgement or personal attacks. It was a very helpful
reminder of what needs to be done and given in a friendly way.
> To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CABc8mQUCs0n_dqErNKrXpUJ%2BPYSwf2vrA2UD%3DEhfp62D7NxUHA%40mail.gmail.com.
Reply all
Reply to author
Forward
0 new messages