[R] R cycle to calculate distances

[P.Branco]

It Works now.

Thanks to all.

P.Branco



Gavin Simpson wrote:
> 
> On Mon, 2008-11-17 at 07:20 -0800, P.Branco wrote:
>> Sorry, it does not work.
>> 
>> If I do a rnorm I lose the original values of my vectors, and the
>> equation
>> result must be attained by the use of the original values.
> 
> Dimitris was generating some dummy data to test that the function
> worked. He had to do this because you didn't provide the data to make up
> r1, r2, etc.
> 
> You don't need to do the calls to rnorm, just use your original data,
> stored in those variables/objects.
> 
> If r1, r2 already contain your data, you just need to do:
> 
> dd <- sqrt(0.723523 * outer(r1, s1, "-")^2 + 0.215518 * outer(r2, s2,
> "-")^2)
> dd
> 
> Does that work?
> 
> G
> 
>> 
>> Thanks,
>> P.Branco
>> 
>> 
>> Dimitris Rizopoulos-4 wrote:
>> > 
>> > try this (presented only for two pairs):
>> > 
>> > r1 <- rnorm(49)
>> > r2 <- rnorm(49)
>> > s1 <- rnorm(300)
>> > s2 <- rnorm(300)
>> > 
>> > dd <- sqrt(0.723523 * outer(r1, s1, "-")^2 + 0.215518 * outer(r2, s2, 
>> > "-")^2)
>> > dd
>> > 
>> > I hope it helps.
>> > 
>> > Best,
>> > Dimitris
>> > 
>> > P.Branco wrote:
>> >> Dear all,
>> >> 
>> >> I am for the first time trying to work with R, but I have bumped into
>> a
>> >> problem.
>> >> 
>> >> I have four vectors:
>> >> r1 (49 values)
>> >> r21 (49 values)
>> >> r22 (49 values)
>> >> r3 (49 values)
>> >> s1 (300 values)
>> >> s21 (300 values)
>> >> s22 (300 values)
>> >> s3 (300 values)
>> >> 
>> >> And I would like to calculate the distances from all references (r)
>> sites
>> >> to
>> >> sample (s) site, for that I wrote this equation:
>> >> 
>> >>
>> drs=sqrt(((0.723523*(r1[i]-s1[ii]))^2)+(((-0.215518*(r21[i]-s21[ii]))^2)+((0.518612*(r22[i]-s22[ii]))^2))+((0.283655*(r3[i]-s3[ii]))^2))
>> >> 
>> >> Now how can I run a cycle in order to calculate the distances?
>> >> 
>> >> Could you please help me?
>> >> 
>> >> P. Branco
>> >> 
>> > 
>> > -- 
>> > Dimitris Rizopoulos
>> > Assistant Professor
>> > Department of Biostatistics
>> > Erasmus Medical Center
>> > 
>> > Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
>> > Tel: +31/(0)10/7043478
>> > Fax: +31/(0)10/7043014
>> > 
>> > ______________________________________________
>> > 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.
>> > 
>> > 
>> 
> -- 
> %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
>  Dr. Gavin Simpson             [t] +44 (0)20 7679 0522
>  ECRC, UCL Geography,          [f] +44 (0)20 7679 0565
>  Pearson Building,             [e] gavin.simpsonATNOSPAMucl.ac.uk
>  Gower Street, London          [w] http://www.ucl.ac.uk/~ucfagls/
>  UK. WC1E 6BT.                 [w] http://www.freshwaters.org.uk
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> 
> ______________________________________________
> 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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