Description Usage Arguments Details Value Author(s) References See Also Examples

System of ordinary differential equations for three species Lotka-Volterra competition. For use with `ode`

in the `deSolve`

package.

1 |

`t` |
the time for each integration. |

`n` |
a vector of length three for the population sizes at time = t. |

`parms` |
vector or list of model parameters (see details below). |

The parameters include `r, a`

with the usual meanings. Here the `a`

's are the per capita effects which determine K (`a11 = 1/K1`

).

Returns a list of length one which is the rate of increase (required by `ode`

).

Hank Stevens <HStevens@muohio.edu>

Lotka, A.J. (1956) *Elements of Mathematical Biology*. Dover Publications, Inc.

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 12 13 14 15 16 17 18 19 20 21 22 | ```
## 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] - a13 *
n[3])
dn2dt <- r2 * n[2] * (1 - a22 * n[2] - a21 * n[1] - a23 *
n[3])
dn3dt <- r3 * n[3] * (1 - a33 * n[3] - a31 * n[1] - a32 *
n[2])
list(c(dn1dt, dn2dt, dn3dt))
})
}
library(deSolve)
parms <- c(r1 = 0.1, r2 = 0.2, r3 = 0.3,
a11 = 0.1, a12 = 0.01, a13 = 0.01,
a21 = 0.01, a22 = 0.15, a23 = 0.01,
a31 = 0.01, a32 = 0.01, a33 = 0.2)
initialN <- c(1, 1, 1)
out <- ode(y = initialN, times = 1:100, func = lvcomp3, parms = parms)
matplot(out[, 1], out[, -1], type = "l")
``` |

primer documentation built on May 19, 2017, 10:05 p.m.

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