[R] Calculate an equation

[P.Branco]

I tried to do some cycles using the “for” function, but then I had to make
multiple “for”s and it didn’t work. One of the major problems is that I
don’t know how to use the summation function on R.

Best regards,

P.Branco

stephen sefick wrote:
> 
> What have you tried so far?
> 
> On Thu, Nov 20, 2008 at 7:40 AM, P.Branco <pjlbranco at yahoo.com> wrote:
>>
>> Dear all,
>>
>> I was wondering if you could help me with the following.
>>
>> I want to do calculate this equation:
>>
>> Ps(t)=  (∑_(r=1)^N Xtr* 1/√drs)/(∑_(r=1)^N 1/√drs)
>>
>> Ps(t) – Probability that taxon t will occur at site s (300 sites s)
>> N – Number of sites = from 1 to 49
>> Xtr – Value for taxon t at site r (I have this information in a table, 40
>> taxa (columns) t, 49 sites r)
>> drs – Distance from site r to site s (this information is on a table, s
>> sites (columns))
>>
>> I thought that R would be the software to use, but I am experiencing some
>> difficulties
>>
>> Thanks to everyone,
>> P.Branco
>>
>> --
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list
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>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
> 
> 
> 
> -- 
> Stephen Sefick
> Research Scientist
> Southeastern Natural Sciences Academy
> 
> Let's not spend our time and resources thinking about things that are
> so little or so large that all they really do for us is puff us up and
> make us feel like gods.  We are mammals, and have not exhausted the
> annoying little problems of being mammals.
> 
> 								-K. Mullis
> ______________________________________________
> 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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