[R] Moving-Tiles Bootstrap

Jeff Newmiller jdnewmil at dcn.davis.ca.us
Wed Jan 25 01:41:59 CET 2012


I wouldn't characterize the requirement to provide R code as simply "nuts and bolts", but rather a preference for precision in communication. Very definitely there are theoretical discussions here, but for such discussions short R examples are used to make sure the concepts are understood.
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Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
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Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
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Sent from my phone. Please excuse my brevity.

Kim Elmore <kim.elmore at noaa.gov> wrote:

>I wish to proffer my sincere apologies to both you and the list. I had 
>not seen my posting appear -- it was initially held for moderator 
>approval, but I never saw that it was released. During the subscription
>
>process, I had used an incorrect e-mail address and so withdrew the 
>post. Within my subscription settings, I had asked to see my own 
>postings but, so far have not. I have now doubled checked that this is 
>the case. Hence, the multiple posts. Again, apologies. Finally, this 
>seems to be a more nuts-and-bolts list and that is not intended to 
>address the admittedly esoteric topic about which I posted my query so,
>
>again, apologies to all. Finally, I think I have set Thunderbird to 
>strip off all HTML in this posting. Again, apologies for the HTML in 
>prior posts -- I certainly intend for there to be none in this one.
>
>Kim Elmore
>
>On 1/24/2012 11:31 AM, Jeff Newmiller wrote:
>> A) Reposting the same message as a separate thread is bad netiquette.
>>
>> B) Posting HTML email on this list is strongly discouraged.
>>
>> C) You probably ought to read the posting guide.
>>
>> D) This is a list about using R. Posting theoretical questions
>without corresponding R code that illustrates what how far you have
>progressed is unlikely to elicit a response.
>>
>> E) Some questions require just the right combination of expertise and
>free time to answer. Yours seems to be bleeding into a theoretical
>discussion of a very specific knowledge domain... I certainly don't
>know the answer. You may need to correspond with authors of packages
>that almost apply to your problem or post on a more focused discussion
>group (perhaps one that discusses statistical theory) if you don't get
>an answer here. Or just wait a week for the right person to read your
>question.
>>
>---------------------------------------------------------------------------
>> 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.
>>
>> Kim Elmore<kim.elmore at noaa.gov>  wrote:
>>
>>> I wish to perform moving tiles bootstrap resampling on some gridded
>>> data
>>> meteorological data. I've many years experience with S-Plus, but it
>has
>>>
>>> no way to perform a moving-tiles bootstrap. Within R I've learned
>how
>>> to
>>> use quadratresample() with the spatstats package and would be happy
>to
>>> simply use empirical percentiles if generating the replicates were
>>> fast,
>>> but it isn't. So, I'd like to employ bootstrap tilting to generate
>my
>>> confidence intervals. On my machine (older Athlon, XP sp3, 4 GB) it
>>> took
>>> about 48 h to generate 5000 moving tiles replicates. But, the boot
>>> package contains boot.tilt and I should be able to do well enough
>with
>>> the statistics I need (mean and RMS) to get by with several hundred
>>> samples instead of several thousand.
>>>
>>> I can certainly build a function that generates the statistic I want
>> >from a moving-tiles replicate. My problem is that the resampling
>>> process
>>> isn't as simple as boot.tilt() expects (I'm not simply resampling
>rows
>>> of a data frame). But, the function that does what I need doesn't
>fit
>>> into how boot.tilt() expects the resampling process to work. I can
>>> generate a string of replicates easily enough -- how might I wrap
>such
>>> a
>>> set of replicates into an object on which tilting could be performed
>>> absent the internal generation of the replicates themselves?
>>>
>>> Kim Elmore
>>> -- 
>>>
>>> Kim Elmore, Ph.D. (CCM, PP SEL/MEL/Glider, N5OP, 2nd Class
>>> Radiotelegraph, GROL)
>>>
>>> /"Human beings, who are almost unique in having the ability to learn
>> >from the experience/
>>> /of//others, are also remarkable for their apparent disinclination
>to
>>> do
>>> so/."/-- Douglas Adams/
>>>
>>>
>>> 	[[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> 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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