nobs.dynrModel {dynr}

Extract the number of observations for a dynrModel object

Description

Extract the number of observations for a dynrModel object

Usage

## S3 method for class 'dynrModel'
nobs(object, ...)

Arguments

object

An unfitted model object

...

Further named arguments. Ignored.

Details

We return the total number of rows of data, adding up the number of time points for each person. For some purposes, you may want the mean number of observations per person or the number of people instead. These are not currently supported via nobs.

Value

A single number. The total number of observations across all IDs.

Examples

# Create a minimal uncooked model called 'model'
# That is, without esimating parameters
require(dynr)

meas <- prep.measurement(
	values.load=matrix(c(1, 0), 1, 2),
	params.load=matrix(c('fixed', 'fixed'), 1, 2),
	state.names=c("Position","Velocity"),
	obs.names=c("y1"))

ecov <- prep.noise(
	values.latent=diag(c(0, 1), 2),
	params.latent=diag(c('fixed', 'dnoise'), 2),
	values.observed=diag(1.5, 1),
	params.observed=diag('mnoise', 1))

initial <- prep.initial(
	values.inistate=c(0, 1),
	params.inistate=c('inipos', 'fixed'),
	values.inicov=diag(1, 2),
	params.inicov=diag('fixed', 2))

dynamics <- prep.matrixDynamics(
	values.dyn=matrix(c(0, -0.1, 1, -0.2), 2, 2),
	params.dyn=matrix(c('fixed', 'spring', 'fixed', 'friction'), 2, 2),
	isContinuousTime=TRUE)

data(Oscillator)
data <- dynr.data(Oscillator, id="id", time="times", observed="y1")

model <- dynr.model(dynamics=dynamics, measurement=meas,
	noise=ecov, initial=initial, data=data)

# Now get the total number of observations!
nobs(model)