[R] Finding Infimum in R

Boris Steipe boris.steipe at utoronto.ca
Mon Apr 10 10:57:49 CEST 2017


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
>>>> 
>>>> ______________________________________________
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>>>> 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.



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