[R] moving distance between two sets of data

[David Winsemius]

On Aug 19, 2012, at 4:34 PM, White, William Patrick wrote:

> Also it occurred to me that my initial explanation was not  
> explicitly clear as to what the desired output is. What I am trying  
> to get is a moving absolute deviation between the two sets of numbers.

The phrase "a moving absolute deviation" admits of several  
interpretations. I suggest you post the correct answer for some simple  
cases or that you be more mathematical in your description (as is  
suggested in the Posting Guide.)

set.seed(123)
  X <- sample(-5:5, 10)
  Y <- sample(-5:5, 10);

 > X
  [1] -2  2  5  4  1 -5 -3  3 -4  0
 > Y
  [1]  5 -1  1  4 -5  0 -4  3 -2  2
 > abs( tail(X,9) - head(Y,9) )
[1] 3 6 3 3 0 3 7 7 2

So this is c( abs(X[2] -Y[1]), abs( X[3]-Y[2], .....)

> This is not to be confused with the mean absolute deviation, or the  
> median absolute deviation which are both something different and not  
> what i am after.

Again. Not a clear description (of what you do do not want), given  
that the problem involves two vectors.

> ________________________________________
> From: David Winsemius [dwinsemius at comcast.net]
> Sent: Sunday, August 19, 2012 4:03 PM
> To: David Winsemius
> Cc: White, William Patrick; r-help at r-project.org
> Subject: Re: [R] moving distance between two sets of data
>
> On Aug 19, 2012, at 12:58 PM, David Winsemius wrote:
>
>>
>> On Aug 19, 2012, at 12:04 PM, White, William Patrick wrote:
>>
>>> On the surface this seems pretty simple, but I flummoxed. I have
>>> two sets of numbers they bounce around zero, positive one and
>>> negative one. They have a relationship between them, where one
>>> diverges away from the other. I want create a second set of numbers
>>> that tracks that divergence.
>>>
>>> #Lets make some data like mine, kinda
>>> Firstset <- runif(100, min = -1 , max =1)
>>> Secondset <- runif(100, min = -1 , max =1)
>>>
>>> #So something like:
>>> Divergence <- abs (Firstset - Secondset)
>>>
>>> #but this doesn't work because when Firstset is at .5 and Secondset
>>> is at  -.25 it returns .25 instead of .75
>>
>> abs( .5 - (-.25) ) should NOT return .25 so you need to produce a
>> better example or point to specifics in the example you offered. If
>> what you wanting what you are getting, then use set.seed(123) and
>> refer to specific values.
> I meant to write:  "If you are not getting what you are wanting .... "
>>
>>> abs( .5 - (-.25) )
>> [1] 0.75
>>
>> --
>> David.
>>
>>>
>>> #another possibility is:
>>>
>>> Divergence <- abs (Firstset) - abs (Secondset)
>>>
>>> #but when Firstset is at .5 and Secondset is at -.5 it returns 0
>>> instead of 1
>>>
>>> #It seems like there is a better way to do this. Any ideas?
>>> ______________________________________________
>>> 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.
>>
>> David Winsemius, MD
>> Alameda, CA, USA
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> Alameda, CA, USA
>
>
>

David Winsemius, MD
Alameda, CA, USA