Category Archives: Miscellaneous

Statistics and the Murder of Erik Tornblom

I read a news story about the use of statistics in the criminal justice system. The case involved the murder of Erik Tornblom by a man named Marcus Robinson. Erik was 17-year old high school student who worked at a … Continue reading

Example of the Tortoise and Hare Algorithm

The tortoise and hare algorithm is a technique to determine if a linked list is circular or not. Briefly, if you set two pointers, p and q, to the start of a linked list, and then iterate by advancing p … Continue reading

The Chinese Restaurant Process

The Chinese Restaurant Process is very simple and best explained by example. Suppose there is a Chinese restaurant that has 4 tables. There are currently 7 customers: 4 customers at table #1, 2 customers at table #2, 1 customer at … Continue reading

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Quantum Circuits

I’ve been reading about quantum computing for many years. I’m a pretty smart guy, but I have extreme difficulty grasping quantum. There are several issues, not the least of which is that quantum is extremely deep and difficult. Anyway, I … Continue reading

The Discrete Logarithm Problem

The discrete logarithm problem is used in cryptography. Given values for a, b, and n (where n is a prime number), the function x = (a^b) mod n is easy to compute. For example, if a = 3, b = … Continue reading

Computing a Stirling Number of the Second Kind from Scratch Using Python

A “Stirling number of the second kind” — S(n, k) — is the number of ways to partition n items into k subsets. For example, the number of ways to group n=4 items into k=2 subsets is 7. Suppose the … Continue reading

The Diffie–Hellman Key Exchange

One of the most fundamental ideas in computer security is called the Diffie-Hellman key exchange algorithm. Suppose you have some sort of cryptography system where two people need the same key to encrypt and decrypt messages. One example of this … Continue reading

The Linda Programming Language

Years ago when I was a university professor, I remember talking about the Linda programming language for a few minutes in a graduate computer science class. What is Linda and what happened to it? First, Linda isn’t really a standalone … Continue reading

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A Full Cycle Generator in Python

Suppose you set n = 10 and you want to generate the ten numbers 0 through 9 in a scrambled way. The technique I usually use is to create an array with 10 cells, initialized to the values 0 to … Continue reading