array-simulate: Simulate data from array.

In gRbase: A Package for Graphical Modelling in R

Simulate data from array.

Description

Simulate data (slice of) an array: Simulate n observations from the array x conditional on the variables in margin (a vector of indices) takes values given by margin.value

Usage

simulateArray(x, nsim = 1, margin, value.margin, seed = NULL)

## S3 method for class 'table'
simulate(object, nsim = 1, seed = NULL, margin, value.margin, ...)

## S3 method for class 'xtabs'
simulate(object, nsim = 1, seed = NULL, margin, value.margin, ...)

## S3 method for class 'array'
simulate(object, nsim = 1, seed = NULL, margin, value.margin, ...)

Arguments

x, object	An array.
nsim	Number of cases to simulate.
margin, value.margin	Specification of slice of array to simulate from.
seed	Seed to be used for random number generation.
...	Additional arguments, currently not used.

Value

A matrix.

Note

The current implementation is fragile in the sense that it is not checked that the input argument x is an array.

Author(s)

Søren Højsgaard, [e-mail]

Examples

## 2x2 array
x <- parray(c("a", "b"), levels=c(2, 2), values=1:4)

x <- tabNew(c("a", "b"), levels=c(2, 2), values=1:4)

## Simulate from entire array
s <- simulateArray(x, 1000)
xtabs(~., as.data.frame(s))

## Simulate from slice defined by that dimension 1 is fixed at level 2
s <-simulateArray(x, 1000, margin=1, value.margin=2)
xtabs(~., as.data.frame(s))

## 2 x 2 x 2 array
x <- parray(c("a", "b", "c"), levels=c(2, 2, 2), values=1:8)
## Simulate from entire array
s <-simulateArray(x, 36000)
xtabs(~., as.data.frame(s))

## Simulate from slice defined by that dimension 3 is fixed at level 1
s <-simulateArray(x, 10000, 3, 1)
xtabs(~., as.data.frame(s))

gRbase documentation built on Oct. 22, 2024, 5:06 p.m.