rand_unit: Pseudo-random numbers on [0, 1) based on a linear...

In xfun: Supporting Functions for Packages Maintained by 'Yihui Xie'

Pseudo-random numbers on ⁠[0, 1)⁠ based on a linear congruential generator

Description

Generate pseudo-random numbers from X_{i+1} = (aX_i + c) \bmod{m}, where X_1 is the initial value (seed).

Usage

rand_unit(n = 1, a = 55797, c = 0, m = 4294967296, seed = NULL)

Arguments

n	The desired length of the sequence.
a, c, m	Parameters for the generator (see References for the default values).
seed	The seed. The default is the system time when this function is called for the first time in the current session. For subsequent calls, the last X_i of the previous call will be used as the default seed.

Value

Random numbers on ⁠[0, 1)⁠ (i.e., X/m instead of X). Note the unit interval is open on the right (excluding 1).

Note

All argument values must be smaller than 2^{64} as they will be coerced to 64-bit integers.

References

Steele, Guy L. Jr.; Vigna, Sebastiano (2022). "Computationally easy, spectrally good multipliers for congruential pseudorandom number generators". Software: Practice and Experience. 52 (2): 443–458.

Examples

rand_unit(10)
rand_unit(10, seed = 0)
rand_unit(10, seed = 0)  # identical results
rand_unit(10, seed = Sys.getpid())

xfun documentation built on April 3, 2025, 7:04 p.m.