On 2014-06-23, Dima Pasechnik <dimp...@gmail.com> wrote: > On 2014-06-23, Karl Schultheisz <art.live...@gmail.com> wrote: >> I'm using Sage 6.2 on Arch Linux. I have posted before about sums being >> wrong >><https://groups.google.com/d/msg/sage-support/IgC78rcdO7c/qTWzpA9f-P8J>, >> and I am happy to see that the community took action. Thanks! I have been >> seeing other errors that may or may not be related to those addressed in >> the link above. >> >> I open a new Sage session (command line). The following code ought to >> return (e^x - 1)/x. >> >> sage: k = var('k') >> sage: sum(x^k/factorial(k+1),k,0,oo) >> 1/4*sqrt(pi)*sqrt(x)*e^(1/2*x) >> >> This looks similar to the sort of nonsense it was spitting out when >> misinterpreting >> Bessel functions from Maxima <http://trac.sagemath.org/ticket/16224>. In >> the same session, if I run the summation command again, the result is > > did you try applying the patch from #16224 ?
Note that on Sage 6.3.beta4, which contains the fix from #16224, I get sage: sum(x^k/factorial(k+1),k,0,oo) 2*sqrt(pi)*sqrt(1/(pi*x))*e^(1/2*x)*sinh(1/2*x)/sqrt(x) which is correct (up to a failure to get obvious simplifications) > >> different. >> >> sage: sum(x^k/factorial(k+1),k,0,oo) >> sum(x^k/factorial(k + 1), k, 0, +Infinity) >> >> And after this it will not simplify any sums, even ones it would have done >> correctly on the first try: >> >> sage: sum(x^k/factorial(k),k,0,oo) >> sum(x^k/factorial(k), k, 0, +Infinity) >> >> Even a reset doesn't help. (As a side-note, the exit command doesn't >> survive reset.) >> >> sage: reset() >> sage: k = var('k') >> sage: sum(x^k/factorial(k),k,0,oo) >> sum(x^k/factorial(k), k, 0, +Infinity) >> sage: exit >> >> --------------------------------------------------------------------------- >> NameError Traceback (most recent call >> last) >> /opt/sage/local/lib/python2.7/site-packages/sage/all_cmdline.py in >><module>() >> ----> 1 exit >> >> NameError: name 'exit' is not defined >> >> Finite sums seem to be ok. >> >> sage: sum(x^k,k,0,3) >> x^3 + x^2 + x + 1 >> sage: m = var('m') >> sage: sum(x^k,k,0,m) >> (x^(m + 1) - 1)/(x - 1) >> >> Any help is greatly appreciated. >> > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.