Hmm. Try setting extendInt="yes" in the call to uniroot. You should also look at the help page for uniroot. help(uniroot) May give you a clue. It's difficult for me to debug code on my iphone. Well, more difficult than usual.
Best, Simon. Sent from my iPhone On 30 Jun 2014, at 8:53 pm, "Mark Christjani" <m_christj...@gmx.de<mailto:m_christj...@gmx.de>> wrote: Thank you, Simon, for your input. Data import works fine now, but the final equation still won`t work. Console reads now: > setwd("c:/Mark") > > table <- read.table("r-TCO-Scene-Kontrolle.csv", header=TRUE, sep=";") > > table x lx mx 1 1 1.0 0.0 2 2 1.0 0.0 3 3 1.0 0.0 4 4 1.0 0.0 5 5 1.0 0.0 6 6 1.0 0.0 7 7 1.0 0.0 8 8 1.0 0.0 9 9 1.0 0.0 10 10 1.0 0.0 11 11 0.2 3.5 > > x <- c(table$x) > L <- c(table$lx) > m <- c(table$mx) > r.range<- c(0, 5) > > eulerlotka <- function(r) sum(L * m * exp(-r * x)) - 1 > res <- uniroot(f = eulerlotka, interval = r.range, tol = 1e-8) Error in uniroot(f = eulerlotka, interval = r.range, tol = 1e-08) : f() values at end points not of opposite sign > > res$root Error: object 'res' not found Any idea on this "Error in uniroot(f = eulerlotka, interval = r.range, tol = 1e-08) : f() values at end points not of opposite sign"-matter? Kind regards, Mark Gesendet: Montag, 30. Juni 2014 um 12:41 Uhr Von: "Simon Blomberg" <s.blombe...@uq.edu.au<mailto:s.blombe...@uq.edu.au>> An: "Mark Christjani" <m_christj...@gmx.de<mailto:m_christj...@gmx.de>> Cc: "r-help@r-project.org<mailto:r-help@r-project.org>" <r-help@r-project.org<mailto:r-help@r-project.org>> Betreff: Re: [R] Population growthrate with Euler-Lotka Your script is failing at the first hurdle because you data are not being imported properly. You should include header=TRUE. sep=";" In the call to read.table. Cheers. Simon. Sent from my iPhone Sent from my iPhone > On 30 Jun 2014, at 7:10 pm, "Mark Christjani" > <m_christj...@gmx.de<mailto:m_christj...@gmx.de>> wrote: > > > Hi everybody, > > I`m Mark and I do my PhD in biology. I try using R to calculate a population > growth rate of animals grown on different types of food. Our workgroup has a > R-skript to do so, but sadly nobody, who knows how this works. I`ve never > used R before, but got some stuff figured out myself. The skript goes: > > setwd("c:/Mark") > table <- read.table("r-TCO-Scene-Kontrolle.csv") > table > x <- c(table$x) > L <- c(table$lx) > m <- c(table$mx) > r.range<- c(0, 5) > eulerlotka <- function(r) sum(L * m * exp(-r * x)) - 1 > res <- uniroot(f = eulerlotka, interval = r.range, tol = 1e-8) > res$root > > I understood that the first 3 lines are simply to load my data and show it > in the workspace console. The next 4 lines define variables of my .csv table > for R. Thus far, everything works fine. Now comes the Euler-Lotka equation, > but somehow, this does not seem to work out as supposed. I tried to find a > solution on the internet, but I think this formula is somewhat special so I > could not find a suitible solution for my special problem. The console says: > > >> setwd("c:/Mark") >> >> table <- read.table("r-TCO-Scene-Kontrolle.csv") >> >> table > V1 > 1 x;lx;mx > 2 1;1;0 > 3 2;1;0 > 4 3;1;0 > 5 4;1;0 > 6 5;1;0 > 7 6;1;0 > 8 7;1;0 > 9 8;1;0 > 10 9;1;0 > 11 10;1;0 > 12 11;0.2;3.5 >> >> x <- c(table$x) >> L <- c(table$lx) >> m <- c(table$mx) >> r.range<- c(0, 5) >> >> eulerlotka <- function(r) sum(L * m * exp(-r * x)) - 1 >> res <- uniroot(f = eulerlotka, interval = r.range, tol = 1e-8) > Error in uniroot(f = eulerlotka, interval = r.range, tol = 1e-08) : > f() values at end points not of opposite sign >> >> res$root > > Does anybody have an idea how to get this running? > > Thanks in advance > > Kind regards > Mark > ______________________________________________ > R-help@r-project.org<mailto: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. [[alternative HTML version deleted]] ______________________________________________ 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.
