randu {base} | R Documentation

## Random Numbers from Congruential Generator

### Description

400 triples of successive random numbers were taken from the VAX FORTRAN function RANDU running under VMS 1.5.

### Usage

    data(randu)

### Format

A data frame with 400 observations on 3 variables named `x`, `y` and `z` which give the first, second and third random number in the triple.

### Details

In three dimensional displays it is evident that the triples fall on 15 parallel planes in 3-space. This can be shown theoretically to be true for all triples from the RANDU generator.

These particular 400 triples start 5 apart in the sequence, that is they are ((U[5i+1], U[5i+2], U[5i+3]), i= 0, ..., 399), and they are rounded to 6 decimal places.

Under VMS versions 2.0 and higher, this problem has been fixed.

### Source

David Donoho

### Examples

    ## We could re-generate the dataset by the following R code
    seed <- as.double(1)
    RANDU <- function() {
        seed <<- ((2^16 + 3) * seed)
        seed/(2^31)
    }
    for(i in 1:400) {
        U <- c(RANDU(), RANDU(), RANDU(), RANDU(), RANDU())
        print(round(U[1:3], 6))
    }

[Package Contents]