Talk:Retention uniformity

Calculation
Doesn't seem to add much to the article so moved to talk. RJFJR (talk) 14:25, 28 June 2010 (UTC)

The calculation of the RU requires some operations and is quite difficult to perform in spreadsheets. The following implementations may help. They take the vector of Rf values, returning the single RU value.

The R (programming language)/S-PLUS implementation:

ru <- function (x) {       x <- sort(x) n <- length(x) i <- (1:n)/(n+1) s <- sum((x-i)^2) ru <- 1-sqrt( (6*(n+1)) / (n*(2*n+1)) * s ); return(ru);

}

The GNU Octave/Matlab implementation:

function res = ru(x) x = sort(x); n = length(x); i = (1:n)./(n+1); s = sum((x-i).^2); res = 1-sqrt((6.*(n+1))./(n.*(2.*n+1)).*s); endfunction

The Scilab implementation:

function res = ru(x) x = gsort(x,"g","i"); n = length(x); i = (1:n)./(n+1); s = sum((x-i).^2); res = 1-sqrt((6.*(n+1))./(n.*(2.*n+1)).*s); endfunction