[Pomp-commits] r157 - in pkg: data man

[noreply at r-forge.r-project.org]

Author: kingaa
Date: 2009-07-07 16:46:07 +0200 (Tue, 07 Jul 2009)
New Revision: 157

Added:
   pkg/data/verhulst.rda
   pkg/man/verhulst.Rd
Log:
add stochastic Verhulst-Pearl (logistic) model to the set of examples

Added: pkg/data/verhulst.rda
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Property changes on: pkg/data/verhulst.rda
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Added: pkg/man/verhulst.Rd
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--- pkg/man/verhulst.Rd	                        (rev 0)
+++ pkg/man/verhulst.Rd	2009-07-07 14:46:07 UTC (rev 157)
@@ -0,0 +1,27 @@
+\name{verhulst}
+\alias{verhulst}
+\docType{data}
+\title{Simple Verhulst-Pearl (logistic) model.}
+\description{
+  \code{verhulst} is a \code{pomp} object encoding a univariate stochastic logistic model with measurement error.
+}
+\usage{data(verhulst)}
+\details{
+  The model is written as an Ito diffusion, \eqn{dn = r n (1-n/K) dt + \sigma n dW}, where \eqn{W} is a Wiener process.
+  It is implemented using the \code{\link{euler.simulate}} plug-in.
+}
+\examples{
+data(verhulst)
+plot(verhulst)
+coef(verhulst)
+params <- cbind(
+                c(n.0=100,K=10000,r=0.2,sigma=0.4,tau=0.1),
+                c(n.0=1000,K=11000,r=0.1,sigma=0.4,tau=0.1)
+                )
+x <- simulate(verhulst,params=params,states=TRUE)
+matplot(time(verhulst,t0=TRUE),t(x['n',,]),type='l')
+y <- trajectory(verhulst,params=params)
+matlines(time(verhulst,t0=TRUE),t(y['n',,]),type='l',lwd=2)
+}
+\seealso{\code{\link{pomp-class}} and the vignettes}
+\keyword{datasets}