fit3models.alt {paleoTSalt}R Documentation

Do model fits for three evolutionary models (alternate parameterization)

Description

Function fits three models to an evolutionary time series: (1) general random walk, (2) unbiased random walk, and (3) stasis.

Usage

fit3models.alt(y, pool = TRUE, silent = FALSE, wts = "AICc")

Arguments

y a paleoTS object
pool logical, if TRUE, variances are pooled across samples
silent logical, if TRUE, results are not printed
wts what version of AIC to use for calculation of Akaike weights; either AIC or AICc

Value

If silent=FALSE, function fit3models.alt returns a vector of parameter estimates; if silent=TRUE, a list with the following components is returned, with models listed in the order of general random walk, unbiased random walk, and stasis:

aic Akaike information criterion
aicc bias-corrected AIC
logl log-likelihoods of the three models
hats parameter estimates for general random walk (mstep, vstep), unbiased random walk (vstep) and stasis (theta, omega) models
ak.wts vector of Akaike weights

Warning

This function uses the alternate parameterization, and so its output is not comparable to those from paleoTS package.

Author(s)

Gene Hunt

References

Hunt, G. 2006. Fitting and comparing models of phyletic evolution: random walks and beyond. Paleobiology32:578–601.

See Also

opt.alt.GRW, fit3models

Examples

 x1<- sim.GRW(ns=30, ms=0.5, vs=0.2)
 fit3models.alt(x1)
 x2<- sim.Stasis(ns=30, theta=10, omega=0) 
 fit3models.alt(x2)

[Package paleoTSalt version 0.1-1 Index]