logL.RW {paleoTS}R Documentation

Compute log-likelihoods for random walk and stasis models

Description

Returns log-likelihood for general random walk logL.RW, unbiased random walk logL.RWu, and stasis logL.stasis models.

Usage

logL.RW(p, y, pool = TRUE)
logL.RWu(p, y, pool = TRUE)
logL.stasis(p, y, pool = TRUE)

Arguments

p vector of parameters
y a paleoTS object
pool logical, if TRUE, variances are pooled across samples

Details

For the general random walk, p = c(mstep, vstep); for an unbiased random walk, p = vstep; for the stasis model, p = c(theta, omega). In general, users will not be access these functions directly, but instead use the optimization functions, which use these functions to find the best-supported parameter values.

Value

The log-likelihood of the parameter estimates (p), given the data (y).

Author(s)

Gene Hunt

References

Hunt, G. 2007. Fitting and comparing models of phyletic evolution: random walks and beyond. Paleobiology32:578–601.

See Also

mle.rw, opt.RW

Examples

y<- sim.rw(20, 0, 1)
L1 <- logL.RW(p=c(0,1), y)   # actual parameters
L2 <- logL.RW(p=c(10,10), y) # should be a bad guess
cat (L1, L2, "\n")

[Package paleoTS version 0.1-2 Index]