# dlaruv (l) - Linux Man Pages

## dlaruv: returns a vector of n random real numbers from a uniform (0,1)

## NAME

DLARUV - returns a vector of n random real numbers from a uniform (0,1)## SYNOPSIS

- SUBROUTINE DLARUV(
- ISEED, N, X )

- INTEGER N

- INTEGER ISEED( 4 )

- DOUBLE PRECISION X( N )

## PURPOSE

DLARUV returns a vector of n random real numbers from a uniform (0,1) distribution (n <= 128).This is an auxiliary routine called by DLARNV and ZLARNV.

## ARGUMENTS

- ISEED (input/output) INTEGER array, dimension (4)
- On entry, the seed of the random number generator; the array elements must be between 0 and 4095, and ISEED(4) must be odd. On exit, the seed is updated.
- N (input) INTEGER
- The number of random numbers to be generated. N <= 128.
- X (output) DOUBLE PRECISION array, dimension (N)
- The generated random numbers.

## FURTHER DETAILS

This routine uses a multiplicative congruential method with modulus 2**48 and multiplier 33952834046453 (see G.S.Fishman,aqMultiplicative congruential random number generators with modulus 2**b: an exhaustive analysis for b = 32 and a partial analysis for b = 48aq, Math. Comp. 189, pp 331-344, 1990).

48-bit integers are stored in 4 integer array elements with 12 bits per element. Hence the routine is portable across machines with integers of 32 bits or more.