Description Usage Arguments Details Value Author(s) References See Also Examples
The S-I-R epidemilogical disease model with births and deaths (population
dynamics), for use with ode
in the deSolve
package. This
model uses mass action transmission.
1 |
t |
times points for which values will be returned |
y |
the vector of disease states of hosts (S, I, R) |
p |
a vector of parameters |
The user does not put these directly into this function, but rather uses
ode
in the deSolve
package.
Returns of list of one component (required by ode
).
Hank Stevens <HStevens@muohio.edu>
Ellner, S.P. and Guckenheimer, J. (2006) Dynamic Models in Biology, Princeton University Press.
Kermack, W.O. and McCormick, W.G. (1927) A contribution to the mathematical theory of epidemics. Proceedings of the Royal Society, Series A, 115, 700–721.
Stevens, M.H.H. (2009) A Primer of Ecology with R, Use R! Series. Springer.
1 2 3 4 5 6 7 8 9 10 11 | library(deSolve)
N <- 10^6; R <- 0; I <- 1; S <- N - I - R
g <- 1/(13/365); b <- 1/50;
age <- 5; R0 <- 1 + 1/(b*age)
B <- R0 * (g + b) / N
parms <- c(B = B, g = g, b = b, m=b)
years <- seq(0,30, by=.1)
SIRbd.out <- data.frame(ode(c(S=S,I=I,R=R), years, SIRbd, parms, hmax=.01))
matplot(SIRbd.out[,1], sqrt(SIRbd.out[,-1]), type='l',
lty=1:3, ylab="sqrt(No. of Individuals)", xlab='Years')
legend('right', c('S','I','R'), lty=1:3, col=1:3, bty='n')
|
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