On 26-01-2013, at 12:31, Andras Farkas <motyoc...@yahoo.com> wrote: > > Sorry Jeff, probably the new version of Yahoo mail doing the html, I switched > back to the older one hope that takes care of the problem. Let me clarify the > code below: > > TINF <-1 > a <-c(500,750,1000,1250,1500,1750,2000) > b <-c(8,12,18,24,36,48,60,72,96) > > infcprodessa <-function (D, tin, tau, ts) > (D * (1 - exp(-0.048 * tin))/(tin * (0.048*79) * (1 - exp(-0.048 * > tau)))) * exp(-0.048 * (ts - tin)) > > z <-sapply(1:1, function(n) infcprodessa(a,TINF,b,b-TINF)) > > so I am looking to find the combination of a = 1000 and b = 12, which iz a > value for "z" that would fall between 15 and 20. Sometimes though there may > be more than one combinations that will meet criteria, in that case I would > like to select the combination based on the smallest "a" value that has the > respective "b" value to meet the criteria, >
ab <- expand.grid(a=a,b=b) z <- unlist(sapply(seq_len(nrow(ab)), function(k) infcprodessa(ab[k,1],TINF,ab[k,2],ab[k,2]-TINF))) z.target <- which(z>=15 & z<=20) ab[z.target,] z[z.target] which.min(ab[z.target,][,"a"]) Berend ______________________________________________ R-help@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.
