I probably first saw this matrix in 1960 in John Todd's class at Caltech. But I forgot about it until Tahar Loulou jogged my memory with a comment following my blog post in late May. It deserves a place in our gallery of interesting matrices.... read more >>

MIT's Professor Gil Strang gave two talks in one morning recently at the SIAM annual meeting. Both talks derived from his experience teaching a new course at MIT on linear algebra and neural nets. His first talk, "The Structure of a Deep Neural Net", was in a minisymposium titled "Deep Learning and Deep Teaching", which he organized. Another talk in that minisymposium was by Drexel's Professor Pavel Grinfeld on "An Informal Approach to Teaching Calculus." An hour later, Gil's gave his second talk, "Teaching About Learning." It was an invited talk at the SIAM Conference on Applied Mathematics Education.... read more >>

Here are the first 12 integers from an infinite sequence defined by a deceptively simple rule. Can you see the pattern? Try to predict the next number in the sequence.... read more >>

If you follow this blog regularly, you know that I love fractals. I recently spent a pleasant afternoon in Nashua, New Hampshire, where my daughter Teresa introduced me to Gregory Searle, a fractal artist and computer geek. Here is his logo.... read more >>

Today is Easter Sunday. Why? How is the date of Easter determined?... read more >>

The ACM Special Interest Group on Programming Languages, SIGPLAN, expects to hold the fourth in a series of conferences on the History of Programming Languages in 2020, see HOPL-IV. The first drafts of papers are to be submitted by August, 2018. That long lead time gives me the opportunity to write a detailed history of MATLAB. I plan to write the paper in sections, which I'll post in this blog as they are available.... read more >>

The ACM Special Interest Group on Programming Languages, SIGPLAN, expects to hold the fourth in a series of conferences on the History of Programming Languages in 2020, see HOPL-IV. The first drafts of papers are to be submitted by August, 2018. That long lead time gives me the opportunity to write a detailed history of MATLAB. I plan to write the paper in sections, which I'll post in this blog as they are available.... read more >>

Leslie Fox (1918-1992) is a British numerical analyst who was a contemporary of three men who played such an important role in my education and early professional life, John Todd, George Forsythe, and Jim Wilkinson. Although I saw less of Fox than I did of the others, he was still an important influence in my life.... read more >>

Three-term recurrence relations are the basis for computing Bessel functions.... read more >>

The first computer that I seriously used was the Burroughs 205 Datatron. I actually used two different machines, one at Caltech for two years in 1959-61 and one at the University of Utah in the summer of 1960. Both the technology and the style of usage were wildly different from today's computers.... read more >>