[R] R cycle to calculate distances

P.Branco pjlbranco at yahoo.com
Mon Nov 17 16:20:22 CET 2008


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.

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.
> 
> 

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