Hi Burt,
Yes, the function is monotone increasing and points of discontinuity
are all known.
They are all numbers between 0 and 1. Thanks very much!
Hanna
2017-04-09 16:55 GMT-04:00 Bert Gunter <bgunter.4567 at gmail.com>:
> Details matter!
>
> 1. Are the points of discontinuity known? This is critical.
>
> 2. Can we assume monotonic increasing, as is shown?
>
>
> -- Bert
>
>
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip
)
>
>
> On Sun, Apr 9, 2017 at 1:28 PM, li li <hannah.hlx at gmail.com>
wrote:
> > Dear all,
> > For a piecewise function F similar to the attached graph, I would
like
> to
> > find
> > inf{x| F(x) >=0}.
> >
> >
> > I tried to uniroot. It does not seem to work. Any suggestions?
> > Thank you very much!!
> > Hanna
> >
> > ______________________________________________
> > 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]]
Is the function linear between the discontinuities? Can you give an example of how the function is specified? B.> On Apr 9, 2017, at 8:38 PM, li li <hannah.hlx at gmail.com> wrote: > > Hi Burt, > Yes, the function is monotone increasing and points of discontinuity > are all known. > They are all numbers between 0 and 1. Thanks very much! > Hanna > > > 2017-04-09 16:55 GMT-04:00 Bert Gunter <bgunter.4567 at gmail.com>: > >> Details matter! >> >> 1. Are the points of discontinuity known? This is critical. >> >> 2. Can we assume monotonic increasing, as is shown? >> >> >> -- Bert >> >> >> >> >> Bert Gunter >> >> "The trouble with having an open mind is that people keep coming along >> and sticking things into it." >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) >> >> >> On Sun, Apr 9, 2017 at 1:28 PM, li li <hannah.hlx at gmail.com> wrote: >>> Dear all, >>> For a piecewise function F similar to the attached graph, I would like >> to >>> find >>> inf{x| F(x) >=0}. >>> >>> >>> I tried to uniroot. It does not seem to work. Any suggestions? >>> Thank you very much!! >>> Hanna >>> >>> ______________________________________________ >>> 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.
Then it's trivial. Check values at the discontinuities and find the first where it's <0 at the left discontinuity and >0 at the right, if such exists. Then just use zero finding on that interval (or fit a line if everything's linear). If none exists, then just find the first discontinuity where it's > 0. Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Sun, Apr 9, 2017 at 5:38 PM, li li <hannah.hlx at gmail.com> wrote:> Hi Burt, > Yes, the function is monotone increasing and points of discontinuity are > all known. > They are all numbers between 0 and 1. Thanks very much! > Hanna > > > 2017-04-09 16:55 GMT-04:00 Bert Gunter <bgunter.4567 at gmail.com>: >> >> Details matter! >> >> 1. Are the points of discontinuity known? This is critical. >> >> 2. Can we assume monotonic increasing, as is shown? >> >> >> -- Bert >> >> >> >> >> Bert Gunter >> >> "The trouble with having an open mind is that people keep coming along >> and sticking things into it." >> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) >> >> >> On Sun, Apr 9, 2017 at 1:28 PM, li li <hannah.hlx at gmail.com> wrote: >> > Dear all, >> > For a piecewise function F similar to the attached graph, I would like >> > to >> > find >> > inf{x| F(x) >=0}. >> > >> > >> > I tried to uniroot. It does not seem to work. Any suggestions? >> > Thank you very much!! >> > Hanna >> > >> > ______________________________________________ >> > 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. > >
Are you sure this is trivial? I have the impression the combination of an ill-posed problem and digital representation of numbers might just create the illusion that is so. B.> On Apr 10, 2017, at 12:34 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote: > > Then it's trivial. Check values at the discontinuities and find the > first where it's <0 at the left discontinuity and >0 at the right, if > such exists. Then just use zero finding on that interval (or fit a > line if everything's linear). If none exists, then just find the first > discontinuity where it's > 0. > > Cheers, > Bert > > > Bert Gunter > > "The trouble with having an open mind is that people keep coming along > and sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Sun, Apr 9, 2017 at 5:38 PM, li li <hannah.hlx at gmail.com> wrote: >> Hi Burt, >> Yes, the function is monotone increasing and points of discontinuity are >> all known. >> They are all numbers between 0 and 1. Thanks very much! >> Hanna >> >> >> 2017-04-09 16:55 GMT-04:00 Bert Gunter <bgunter.4567 at gmail.com>: >>> >>> Details matter! >>> >>> 1. Are the points of discontinuity known? This is critical. >>> >>> 2. Can we assume monotonic increasing, as is shown? >>> >>> >>> -- Bert >>> >>> >>> >>> >>> Bert Gunter >>> >>> "The trouble with having an open mind is that people keep coming along >>> and sticking things into it." >>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) >>> >>> >>> On Sun, Apr 9, 2017 at 1:28 PM, li li <hannah.hlx at gmail.com> wrote: >>>> Dear all, >>>> For a piecewise function F similar to the attached graph, I would like >>>> to >>>> find >>>> inf{x| F(x) >=0}. >>>> >>>> >>>> I tried to uniroot. It does not seem to work. Any suggestions? >>>> Thank you very much!! >>>> Hanna >>>> >>>> ______________________________________________ >>>> 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. >> >> > > ______________________________________________ > 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.