nurza m wrote: > Hello, > > I am struggling to find the root of a exponent > function. > "uniroot" is complaining about a values at end points > not of opposite sign?
And you think it is not the case? Why? We cannot help because you have not given a reproducible example (What is w and gp?), which the posting guide asks you to do. Please also format your code in a way that is easy for others to read, including some blanks and without all those ">" and "+": saeqn <- function(s, l) { p <- exp(-l$gp$lambda + s) * l$gp$c k11 <- (l$gp$mu * (l$gp$lambda^2) * l$gp$c - s * l$gp$lambda * l$gp$c * l$gp$mu + l$gp$mu * l$gp$lambda) * p k12 <- -l$gp$mu * l$gp$lambda - s^2 + 2 * s * l$gp$lambda - (l$gp$lambda^2) k13 <- k11 + k12 k14 <- (l$gp$lambda - s) * (-l$gp$mu * s - s * l$gp$lambda + s^2 + l$gp$mu * l$gp$lambda * p) k1 <- -k13 / k14 k1 - l$t } s <- sapply(seq(along = w), function(i) { uniroot(saeqn, lower = -5000, upper = 0.01036597923, l = list(t = w[i], gp = gp))$root } ) > > s<- sapply(1:length(w),function(i) > + { > + > + + > + > + > uniroot(saeqn,lower=-5000,upper=0.01036597923,l=list(t=w[i],gp=gp))$root > + }) > Error in uniroot(saeqn, lower = -5000, upper = > 0.01036597923, l = list(t = w[i], : > f() values at end points not of opposite sign > > > > > and here is my fonction "saeqn". > > > >>saeqn<-function(s,l) > > + { > + > + > + p<- exp(-l$gp$lambda+s)*l$gp$c > + > + > + > k11<-(l$gp$mu*(l$gp$lambda^2)*l$gp$c-s*l$gp$lambda*l$gp$c*l$gp$mu+l$gp$mu*l$gp$lambda)*p > + > + k12 <- > -l$gp$mu*l$gp$lambda-s^2+2*s*l$gp$lambda-(l$gp$lambda^2) > + > + k13 <-k11+k12 > + > + > k14<-(l$gp$lambda-s)*(-l$gp$mu*s-s*l$gp$lambda+s^2+l$gp$mu*l$gp$lambda*p) > + > + k1<- -k13/k14 > + > + k1-l$t > + } > > > > . There is something I must be missing since I never > had > luck with "uniroot"! > > Thanks, > > ______________________________________________ > R-help@stat.math.ethz.ch 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. ______________________________________________ R-help@stat.math.ethz.ch 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.