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.
On 10/04/17 20:57, Boris Steipe wrote:> 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.Fortune nomination. cheers, Rolf -- Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276
Given what she said, how does the procedure I suggested fail? (Always happy to be corrected). -- 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 Mon, Apr 10, 2017 at 1:57 AM, Boris Steipe <boris.steipe at utoronto.ca> wrote:> 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. >
Well - the _procedure_ will give a result.
But think of f(x) = {-1; x <= 1/3 and 1; x > 1/3
What should inf{x| F(x) >= 0} be?
What should the procedure return?
> On Apr 10, 2017, at 10:38 AM, Bert Gunter <bgunter.4567 at gmail.com>
wrote:
>
> Given what she said, how does the procedure I suggested fail?
>
> (Always happy to be corrected).
>
> -- 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 Mon, Apr 10, 2017 at 1:57 AM, Boris Steipe <boris.steipe at
utoronto.ca> wrote:
>> 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.
>>