Take the numbers from 82 stepping down to one, and write them all out together. You get a very big number. 828180797877767574737271706968676665646362616059585756555453525150494847464544\\ 43424140393837363534333231302928272625242322212019181716151413121110987654321 It’s prime. What’s slightly odd is that there are no other numbers constructed the same way for n < 500 which are also prime. Technorati Tags: Mathematics, Prime Numbers Addendum: I got [...]
Archive for month: February, 2007
Perhaps this could be adapted to help me get exercise…. YouTube – Cat wheel II by Richard Norton
My daily sail upon the seas of the Internet blew me ashore on An Introduction to Scheme and its Implementation, a book on implementing Scheme by Paul Wilson. Scheme has a bit of nostalgia for me, having taken a class in Scheme from Will Clinger back in my graduate days at the University of Oregon. [...]
A great collection of links to Classic Texts in Computer Science.
C’mon folks. It’s 2007 for pete’s sake. Why are there still programs which can’t be built on 64 bit machines? Yes, it can be a pain. When we ported the RenderMan with all its mumble mumble lines of code to the DEC Alpha, it was tiring, gritty, annoying, but absolutely necessary. And in the grand [...]
A discussion of how to properly handle liquid inside glasses in a raytracer made me look up the scheme that I had implemented once before, which I’m now stashing a pointer to just for safekeeping. Journal of Graphics Tools – Papers – Simple Nested Dielectrics in Ray Traced Images The reason that this is difficult [...]
Over twenty years ago, I first read Structure and Interpretation of Computer Programs, which I still consider to be the most amazing computer science textbook ever written. I’ve known for a while that one of the author’s, Gerald Sussman has written a book on classical mechanics called (appropriately enough) Structure and Interpretation of Classical Mechanics. [...]
I had the vaguest recollection of a SIGGRAPH sketch on creating an armature wired with potentiometers for creating an inexpensive motion capture setup. A bit of digging revealed that this done by Stefan Gustavson in 2002, and Tom was kind enough to run down this link to his page which somehow eluded by Google-fu.
I’ve worked on computer graphics for over twenty years now. Through some quirk of fate, I have spent nearly all of my time programming batch rendering algorithms that take minutes or even hours (days?) to render pictures. The last time I really did interactive work was before OpenGL even had the “Open” prefix, back when [...]
It’s actually not just hard in the sense that you normally think of as hard. You might think that if you worked hard, you could figure out what programs actually do. Ed Felton shows that this simply isn’t true. In his simple Python scripts, he asks a question: “is there any combination of inputs to [...]
Years ago, I read Gleick’s Chaos, and my recent diversion into calculating various numbers to high degrees of precision made me think about Feigenbaum’s Constant. While I didn’t write a program to compute this constant, I did recall how it is defined, on the basis of this logistic map: Feigenbaum’s constant is the limiting ratio [...]
In between sessions of zelda (currently in the Lake Temple, total elapsed time just over fourteen hours), I’ve been considering just how cool the Wii Remote controllers are. For $40 (admittedly, quite a bit for a controller) you get a controller with the following nifty features: It communicates wirelessly via Bluetooth, which opens up a [...]
Dear me. Macrovision has its panties all in a bunch over Steve Jobs’ recent “Open Letter” which has received a lot of attention in the blogosphere. Macrovision’s Response to Steve Jobs’ Open Letter It contains a lot of howlers, but I thought I’d bring your attention to a few of them. Macrovision admonishes Steve by [...]
Yesterday Tom mentioned this article linked from Lambda The Ultimate the other day, and I finally got around to reading it today. Regular Expression Matching Can Be Simple And Fast | Lambda the Ultimate The short summary: the regular expression matching in common scripting languages like Perl and Python are many orders of magnitude slower [...]