[R] Need help with function that includes 2 summation

Romain Francois rfrancois at mango-solutions.com
Wed Oct 17 14:35:49 CEST 2007

Zack Darnell wrote:
> I am relatively new to R, so this may be a much simpler question than 
> it seems to me. I am trying to create a function that includes two 
> summations, and can't figure out how. I am attaching the equation as a 
> pdf file. This function will then be optimized over a chosen range of 
> values, but right now I just need help with the function. Thank you.
> Zack Darnell
> Duke University

I'm a bit unsure of what you call double summation, I only see the i 
index in here, you can almost translate the latex code into R:

R> sqrt( sum(cos(k*theta))^2 + sum(sin(k*theta))^2  ) / n

theta being a vector containing all your theta_i, for i in 1 to n.



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