Yes, I just looked closer and what is written there is quite confusing. The purpose of the convention is to define what happens when the upper limit is less than the lower limit. I believe it also defines what happens when the limits are nonintegral, but I could be misremembering that. The docstring is correct. It talks about the notation in the Karr paper, which is non-inclusive, and it tries to talk about how that relates to the normal summation notation, which is inclusive (and is what SymPy uses). The section needs to be improved.
Aaron Meurer On Wed, Mar 11, 2020 at 11:37 AM Oscar Benjamin <[email protected]> wrote: > > On Wed, 11 Mar 2020 at 16:58, Aaron Meurer <[email protected]> wrote: > > > > The convention used is actually related to the Karr algorithm, in that > > it is based on the conventions defined in his paper > > https://docs.sympy.org/latest/modules/concrete.html#sympy.concrete.summations.Sum. > > It relates to the way so-called indefinite summations work, which are > > an important part of the algorithm. > > That might be what it says in the docstring but Sum clearly does not > actually use that convention: > > In [6]: Sum(f(n), (n, 1, 4)).doit() > Out[6]: f(1) + f(2) + f(3) + f(4) > > -- > 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 [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sympy/CAHVvXxShNbxx-N5UGd3OXRAXaeLLRgNtGc6syagpPKw6ZXuwOg%40mail.gmail.com. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6Ko8aqtWGE8y-QGP8MQxOzDX7%3D4kATCagbnP1Vt2Z2MAQ%40mail.gmail.com.
