but you get a different hide with sum vs. cumsum. David is right if you want the sum of n terms.
> sum(1/(1:100)^2) - pi^2/6 [1] -0.009950167 > sum(1/(1:1000)^2) - pi^2/6 [1] -0.0009995002 etc. > On Jul 24, 2015, at 7:24 PM, Janh Anni <annij...@gmail.com> wrote: > > Wow! So many (simpler) ways to skin a cat. Thanks! > > On Fri, Jul 24, 2015 at 8:07 PM, David Winsemius <dwinsem...@comcast.net> > wrote: > >> >> On Jul 24, 2015, at 4:37 PM, Janh Anni wrote: >> >>> Hello Jeff, >>> >>> Thanks a lot. I tried it and see that it prints out the entire 100 >> partial >>> sums, so I can take the last value as the partial sum for the first 100 >>> terms. Would there be any way cumsum can print only the nth partial sum, >>> i.e. the last value in the array, instead of printing the entire array? >>> Thanks again. >> >> Wouldn't that just mean using sum instead of cumsum????? >> >> Can even check the error from the analytical limit. >> >>> sum(1/(1:100)^2) - pi^2/6 >> [1] -0.009950167 >> >> >>> >>> Joseph >>> >>> On Fri, Jul 24, 2015 at 2:02 PM, Jeff Newmiller < >> jdnew...@dcn.davis.ca.us> >>> wrote: >>> >>>> Please reply-all so the mailing list stays in the loop. >>>> >>>> cumsum(1/(1:100)^2) >>>> >>>> gives you the partial sums up through i=100. >>>> >> --------------------------------------------------------------------------- >>>> Jeff Newmiller The ..... ..... Go >> Live... >>>> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live >>>> Go... >>>> Live: OO#.. Dead: OO#.. Playing >>>> Research Engineer (Solar/Batteries O.O#. #.O#. with >>>> /Software/Embedded Controllers) .OO#. .OO#. >> rocks...1k >>>> >> --------------------------------------------------------------------------- >>>> Sent from my phone. Please excuse my brevity. >>>> >>>> On July 24, 2015 10:30:09 AM PDT, Janh Anni <annij...@gmail.com> wrote: >>>>> Hello Jeff, >>>>> >>>>> Thank you so much for the suggestion, I searched cumsum as suggested >>>>> but >>>>> not sure it is what I had in mind. For instance if I had the infinite >>>>> series: [image: Inline image 1] >>>>> >>>>> and want to compute the sum of the, say, first 100 terms, how could I >>>>> use >>>>> cusum to do that? >>>>> >>>>> Thanks again, >>>>> >>>>> Janh >>>>> >>>>> >>>>> On Thu, Jul 23, 2015 at 11:51 PM, Jeff Newmiller >>>>> <jdnew...@dcn.davis.ca.us> >>>>> wrote: >>>>> >>>>>> ?cumsum >>>>>> >>>> >>>>> >> --------------------------------------------------------------------------- >>>>>> Jeff Newmiller The ..... ..... Go >>>>> Live... >>>>>> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live >>>>>> Go... >>>>>> Live: OO#.. Dead: OO#.. >>>>> Playing >>>>>> Research Engineer (Solar/Batteries O.O#. #.O#. with >>>>>> /Software/Embedded Controllers) .OO#. .OO#. >>>>> rocks...1k >>>>>> >>>> >>>>> >> --------------------------------------------------------------------------- >>>>>> Sent from my phone. Please excuse my brevity. >>>>>> >>>>>> On July 23, 2015 8:23:39 PM PDT, Janh Anni <annij...@gmail.com> >>>>> wrote: >>>>>>> Dear All, >>>>>>> >>>>>>> Does anyone know of any R functions that compute partial sums of >>>>>>> series? >>>>>>> >>>>>>> Thanks in advance! >>>>>>> >>>>>>> Janh >>>>>>> >>>>>>> [[alternative HTML version deleted]] >>>>>>> >>>>>>> ______________________________________________ >>>>>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>>>>>> https://stat.ethz.ch/mailman/listinfo/r-help >>>>>>> PLEASE do read the posting guide >>>>>>> http://www.R-project.org/posting-guide.html >>>>>>> and provide commented, minimal, self-contained, reproducible code. >>>>>> >>>>>> >>>> >>>> >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. >> >> David Winsemius >> Alameda, CA, USA >> >> > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.