[R] Infinite Series

[Janh Anni]

Thanks Bert!

On Fri, Jul 24, 2015 at 7:57 PM, Bert Gunter <bgunter.4567 at gmail.com> wrote:

> Janh:
>
> It sounds like you really need to go through an R tutorial or two
> before posting further, as this is a pretty basic query. Or am I wrong
> about this?
>
> An answer: Just use indexing
>
> cumsum(1/seq_len(100)^2)[seq(10, to = 100,by = 10)] ## keeps every 10th
>
>  [1] 1.549768 1.596163 1.612150 1.620244 1.625133 1.628406 1.630750
> 1.632512 1.633884
> [10] 1.634984
>
>
> But beware FAQ 7.31 for long series.
>
> Cheers,
> Bert
>
>
> Bert Gunter
>
> "Data is not information. Information is not knowledge. And knowledge
> is certainly not wisdom."
>    -- Clifford Stoll
>
>
> On Fri, Jul 24, 2015 at 4:37 PM, Janh Anni <annijanh at gmail.com> 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.
> >
> > Joseph
> >
> > On Fri, Jul 24, 2015 at 2:02 PM, Jeff Newmiller <
> jdnewmil at 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:<jdnewmil at 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 <annijanh at 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
> >> ><jdnewmil at dcn.davis.ca.us>
> >> >wrote:
> >> >
> >> >> ?cumsum
> >> >>
> >>
> >>
> >---------------------------------------------------------------------------
> >> >> Jeff Newmiller                        The     .....       .....  Go
> >> >Live...
> >> >> DCN:<jdnewmil at 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 <annijanh at 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 at 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 at 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.
>

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