wdm: Bayesian Wiener diffusion model fit functions

In yeagle/BWiener: Wiener diffusion model analysis with Bayesian methods

Description

bwdm creates parameter estimates for the four parameters of the Wiener diffusion model.

Usage

  bwdm(data, yvar=c("q", "resp"), alpha=NULL, tau=NULL, beta=NULL, delta=NULL,
               xvar=NULL, start=NULL, fixed=0, jagscmd=NULL, idvar="id")

Arguments

data	is the data object containing data coming from a (hypothetical) Wiener Diffusion process. For further details on the data object, see is.wiener.
yvar	represents an optional vector, that can be used to define the names of the reaction time column. For further details on the data object, see is.wiener.
alpha	optional, can be used to fix the alpha parameter to the given value.
tau	optional, can be used to fix the tau parameter to the given value.
beta	optional, can be used to fix the beta parameter to the given value.
delta	optional, can be used to fix the delta parameter to the given value.
xvar	optional: group factor variable to estimate all unfixed parameters separate for the given groups.
start	an optional vector with the four starting parameter values in the following order: alpha, tau, beta, delta.
fixed	a number indicating how many of the parameters are fixed (not free). This number will be subtracted from the number of free parameters. Defaults to 0.
jagscmd	a list with options for the jags call. Defaults to NULL which is equal to: list(n.chains=1, n.adapt=1000, n.iter=10000, thin=10).
idvar	variable/factor name defining the individual/person in data in data (typically column name in data.frame), defaults to id. Can be omitted if irrelevant.

Details

The bwdm function calls an mcmc based estimation routine (JAGS with the JAGS Wiener module), to estimate the model parameters.

Examples

## Not run: 
## generate random data
dat <- rbind(cbind(rwiener(100, 2,.3,.5,1), group="A"),
        cbind(rwiener(100,2,.3,.5,-1), group="B"))

## fit wdm
bwdm1 <- bwdm(dat)

## extract parameters
coef(bwdm1)

## further models
bwdm2 <- bwdm(dat, beta=.5)
bwdm3 <- bwdm(dat, alpha=bwdm1$coefficients["alpha"], 
              tau=bwdm1$coefficients["tau"],
              beta=bwdm1$coefficients["beta"], 
              xvar="group")

## End(Not run)

yeagle/BWiener documentation built on May 4, 2019, 2:32 p.m.