The Ampere Porting Advisor Tutorial
This tutorial walks you through building and using the Ampere Porting Advisor and how to mitigate any issues. Continue reading The Ampere Porting Advisor Tutorial on SitePoint.
Read moreDrazin pseudoinverse
The most well-known generalization of the inverse of a matrix is the Moore-Penrose pseudoinverse. But there is another notion of generalized inverse, the Drazin pseudoinverse, for square matrices. If a matrix A has an inverse A−1 then it also has a Moore-Penrose pseudoinverse A+ and a Drazin pseudoinverse AD and A−1 =
Read moreEffective graph resistance
I’ve mentioned the Moore-Penrose pseudoinverse of a matrix a few times, most recently last week. This post will give an application of the pseudoinverse: computing effective graph resistance. Given a graph G, imagine replacing each edge with a one Ohm resistor. The effective resistance between two nodes in G is the electrical
Read moreMultiplying a matrix by its transpose
An earlier post claimed that there practical advantages to partitioning a matrix, thinking of the matrix as a matrix of matrices. This post will give an example. Let M be a square matrix and suppose we need to multiply M by its transpose MT. We can compute this product faster than
Read moreA bit-twiddling marvel
Pop quiz: what does the following code do? bool is_leap_year_fast(uint32_t y) { return ((y * 1073750999) & 3221352463) <= 126976; } It determines whether the year y is a leap year in the Gregorian calendar, of course. :) It’s very efficient, though I don’t image that would ever matter. But
Read moreCEO Update: Exploration and experimentation for bold evolution
As we envision what the ideal future version of Stack Overflow looks like, we’re committed to engaging with our community.
Read moreMatrices of Matrices
It’s often useful to partition a matrix, thinking of it as a matrix whose entries are matrices. For example, you could look at the matrix 6 × 6 as a 2 × 2 matrix whose entries are 3 × 3 matrices. M is not a diagonal matrix of real numbers,
Read moreDurable execution: autosave for your microservices
Ryan is joined by Jeremy Edberg, CEO of DBOS, and Qian Li, co-founder of DBOS, to discuss durable execution and its use cases, its implementation using technologies like PostgreSQL, and its applications in machine learning pipelines and AI systems for reliability, debugging, and observability.
Read moreThese are the top 10 schools in CodeSignal’s 2025 University Ranking Report
Now in its 5th year, CodeSignal’s 2025 University Ranking Report continues to make news headlines by tackling a simple, but bold, question: what are the top schools for software engineering if you look at students’ actual coding skills? That’s a question news outlets like Dice, Government Technology, and NBC Bay
Read moreProbability of rolling a Yahtzee
IJK (iconjack) has calculated the probability of rolling a Yahtzee in no more than n rolls. The first few numerical values are p(1) = 0.0007716 p(2) = 0.0126316 p(3) = 0.0460286 The probability is 0.95 after 23 rolls, and 0.99 after 32 rolls. Here’s a plot. The post Probability of
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