[racket] LC53

From: Hugh Aguilar (hughaguilar96 at yahoo.com)
Date: Sat Nov 17 06:46:50 EST 2012

All of this talk about using Racket for numerical work reminds me of a simple function that I included in my novice package:

This is the LC53 linear-congruential prng (pseudo-random number generator) that I invented. Here it is using infix pseudo-code:
m = 2^32 - 5
a = 2^32 - 333333333
x(n+1) = a*x(n) mod m

Would any brave Racketeer care to implement this in Racket? Hopefully doing so won't involve rewriting the VM and the JIT. :-)

Note that when I invented LC53, the 32-bit x86 was still prevalent and I was assuming that the system would be 32-bit. Implementing LC53 on the 64-bit x86 using 64-bit registers is too easy --- so for this exercise, please assume that you are using a 32-bit processor. As often happens in numerical programs, overflow of intermediate values will be an issue.

BTW --- My novice package also includes a program to crack an encryption system based on LC53 or any other linear-congruential prng.
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