lvcomp2 {primer} | R Documentation |
System of ordinary differential equations for two species Lotka-Volterra competition. For use with ode
in the deSolve
package.
lvcomp2(t, n, parms)
t |
Times points that will return N. |
n |
a vector of length two for the population sizes at time = t. |
parms |
vector or list of model parameters (see details below). |
The parameters include r1, r2, a11, a12, a21, a22
with the usual meanings. Here the a's are the per capita effects which determine K (a11 = 1/K
).
Returns a list of length one which is the rate of increase (required by ode
).
Hank Stevens <HStevens@muohio.edu>
Lotka, A.J. Elements of Mathematical Biology. Dover Publications, Inc., 1956.
Stevens. M.H.H. A Primer of Theoretical Population Ecology with R. Use R! Series. Springer, 2009.
## The function is currently defined as function (t, n, parms) { with(as.list(parms), { dn1dt <- r1 * n[1] * (1 - a11 * n[1] - a12 * n[2]) dn2dt <- r2 * n[2] * (1 - a22 * n[2] - a21 * n[1]) list(c(dn1dt, dn2dt)) }) } library(deSolve) parms <- c(r1 = 1, r2 = 0.1, a11 = 0.2, a21 = 0.1, a22 = 0.02, a12 = 0.01) initialN <- c(1, 1) out <- ode(y = initialN, times = 1:100, func = lvcomp2, parms = parms) matplot(out[, 1], out[, -1], type = "l")