Hello, I am working on a paper of ecological modelling in R. I have made a Lotka Volterra model for tree animal species. I was trying to get the model in R but there are some errors. Since i am not so experienced with R i can't find the bugs in my script. I hope if there is someone who can help me handle this problem. Greetz Roel This is the script i wrote: library(odesolve) LotVmod <- function (Time, State, Pars) { with(as.list(c(State, Pars)), { dx = x*(alpha - beta*y) dy = -y*(gamma - delta*z) dz = z*( Iota ? kappa*y) return(list(c(dx, dy, dz))) }) } Pars <- c(alpha = .405, beta = .81, gamma = 1.5, delta = .125, Iota = 0.35, kappa = 0.75) State <- c(x = 100, y = 100, z = 100) Time <- seq(0, 100, by = 1) out <- as.data.frame(lsoda(func = LotVmod, y = State, parms = Pars, times Time)) matplot(out[,-1], type = "l", xlab = "time", ylab = "population") legend("topright", c("leeuw", "wildebeest",?zebra?), lty = c(1,2,3), col c(1,2,3), box.lwd = 0) -- View this message in context: http://r.789695.n4.nabble.com/Error-in-eco-model-tp2216605p2216605.html Sent from the R help mailing list archive at Nabble.com.