I'm not sure if this is true or not, but even if it is, I find it to be a poor reason for the inconsistency.
Aaron Meurer On Sep 15, 2010, at 6:17 PM, smichr wrote: > > > On Sep 15, 10:56 am, Mark Dewing <markdew...@gmail.com> wrote: >> Is there a reason that limits for sums and integrals are stored >> differently? >> >> For integrals, it appears to be (variable, (lower_limit, upper_limit)) >> and for sums it appears to be (variable, lower_limit, upper_limit) > > Maybe because if the Integral limits are stored as a flat tuple then > you have to look at two quantities after the integration variable to > see what you are dealing with whereas if you store it as a nested > tuple you know what you are dealing with by just looking at the second > item: > - if it is None it is an unevaluated Integral like Integral(x) > - if it is a Tuple, one or both of the upper and lower limits are not > None > > The same semantics don't apply to a Sum which is discrete. One can't > do a sum without knowing the limits in the same way you can do an > integral without the limits. So you always need lower and upper limits > even though this is not enforced (and should probably be changed: > >>>> Sum(x,(x,1)) > Sum(x, (x, 1)) >>>> _.doit() > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File "sympy\concrete\summations.py", line 67, in doit > for i, a, b in self.limits: > ValueError: need more than 2 values to unpack > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to sy...@googlegroups.com. > To unsubscribe from this group, send email to > sympy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sy...@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
