This is part one of a series of posts about John Conway's Game of Life. One deceptively simple rule leads to an incredible variety of patterns, puzzles, and unsolved mathematical problems, and a beautiful use of MATLAB sparse matrices. ... 続きを読む >>

I have been interested in the computation of the matrix exponential, $e^A$, for a long time. A recent query from a user provides a provocative example.... 続きを読む >>

An esoteric fact about matrices is that any real matrix can be written as the product of two symmetric matrices. I've known about this fact for years, but never seriously explored the computational aspects. So I'm using this post to clarify my own understanding of what I'll call the symmetric pair decomposition. It turns out that there are open questions. I don't think we know how to reliably compute the factors. But I also have to admit that, even if we could compute them, I don't know of any practical use.... 続きを読む >>

This is the probably the first article ever written with the title "Symplectic Spacewar". If I Google that title today, including the double quotes to keep the two words together, I do not get any hits. But as soon as Google notices this post, I should be able to see at least one hit. ... 続きを読む >>

h1 { font-size:18pt; } h2.titlebg { font-size:13pt; } h3 { color:#4A4F55; padding:0px; margin:5px 0px 5px; font-family:Arial, Helvetica, sans-serif; font-size:11pt; font-weight:bold;... 続きを読む >>