Dear All,
I am trying to use ode solver "rk4" to solve an ODE system, however, it
keeps saying: Error in eval(expr, envir, enclos) : object "dIN" not found.
The sample codes are enclosed as follows, please help me. Thank you very
much!
rm(list=ls())
library(odesolve)
# The ODE system
ode <- function(t,x,p){
with(as.list(c(x,p)),{
if(IN==0){
dIN <- 1
switch <- c
}
else {
switch <- 0
}
dP1 <- a+b*P1-switch*P1
dP2 <- a-b*P1+switch*P2
list(c(dP1,dP2,dIN))
})
}
# Parameters
a <- 0.1
b <- 0.2
c <- 0.5
parms <- c(a=a,b=b,c=c)
# Initial conditions
P10 <- 100.0
P20 <- 0.0
IN0 <- 0.0
xstart <- c(P1=P10,P2=P20,IN=IN0)
# Time points
times <- seq(0,10,by=1)
out <- as.data.frame(rk4(xstart,times,ode,parms))
[[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.
