Algorithm Used by the LabVIEW Random Number (0 - 1) Function

Issue Details

What is the algorithm used by the LabVIEW Random Number (0 - 1) function, and what is its period?

Solution

The LabVIEW Random Number (0 - 1) function produces numbers seeded by the system clock. When generating random numbers, a "seed" is a starting number that initializes a random number generator. Refer to [External] Random Seed for a more detailed explanation of seeds.

The numbers produced are evenly distributed between 0 and 1, excluding the number 1. The algorithm is based on the use of multiple Multiplicative Congruential Generators (MCGs), also known as Lehmer Generators. Refer to [External] Lehmer Random Number Generator for a detailed explanation of how MCGs work.

This implementation improves the frequency of occurrence of values towards the extremes of the distribution. It has a periodicity of 6.95 * 10^12 random numbers before the cycle repeats. 

A detailed explanation of the algorithm can be found in "An Efficient and Portable Pseudo-random number generator", Applied Statistics 31 (1982), 188-190 by B.A. Wichmann and I.D. Hill.

Additional Information

For applications that require completely different sequences for generating, for example a universally unique identifier (UUID) and not a pseudorandom generator, it is recommended to use a different method such as an external GUID generator.

How to Generate a MessageID/GUID/UUID With LabVIEW? shows an example of using .NET GUID functions to generate a unique identifier.