linear congruential generator


Definition: A class of algorithms that are pseudo-random number generators. The next number is generated from the current one by rn+1 = (A × rn + B) mod M, where A and M are relatively prime numbers.

Generalization (I am a kind of ...)
pseudo-random number generator.

Note: When implemented in software, A and B may be chosen so as to have integer overflow on nearly every step, and therefore have a less predictable sequence and avoid the mod operation. The low-order bits tend to be less random than high-order bits. This is improved by discarding some of the low-order bits. Therefore, the range of random numbers is less than the range of the integer used in the computation.

Better algorithms are available, but they are more complex.

Author: BB

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Entry modified 26 July 2021.
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Cite this as:
Bob Bockholt, "linear congruential generator", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 26 July 2021. (accessed TODAY) Available from: