http://marknelson.us Programming, mostly. Mon, 15 Apr 2013 12:11:06 +0000 en-US hourly 1 http://wordpress.org/?v=3.5.1 http://marknelson.us/2011/02/14/a-big-problem-that-doesnt-need-a-bignum/ http://marknelson.us/2011/02/14/a-big-problem-that-doesnt-need-a-bignum/#comments Tue, 15 Feb 2011 00:10:37 +0000 Mark Nelson http://marknelson.us/?p=292 Calculating a probability that involves k-step Fibonacci numbers can be done without resorting to Bignum classes - and the C++ deque container is a perfect class for the job.]]> http://marknelson.us/2011/02/14/a-big-problem-that-doesnt-need-a-bignum/feed/ 5 http://marknelson.us/2011/01/17/20-heads-in-a-row-what-are-the-odds/ http://marknelson.us/2011/01/17/20-heads-in-a-row-what-are-the-odds/#comments Tue, 18 Jan 2011 02:44:35 +0000 Mark Nelson http://marknelson.us/?p=187 An exercise in probability demonstrates the exact chances of flipping a fair coin k times in a row given n tosses.]]> http://marknelson.us/2011/01/17/20-heads-in-a-row-what-are-the-odds/feed/ 18 http://marknelson.us/2011/01/09/combinatorial-data-compression/ http://marknelson.us/2011/01/09/combinatorial-data-compression/#comments Sun, 09 Jan 2011 23:10:57 +0000 Mark Nelson http://marknelson.us/?p=154 Newcomers to the world of data compression often stumble on this old idea in hopes of creating a novel and powerful algorithm. In a nutshell, the idea is to create an enumerative coding system that uses combinatorial numbering to identify a message, in hopes of providing a more compact representation . Unfortunately, these schemes always [...]]]> http://marknelson.us/2011/01/09/combinatorial-data-compression/feed/ 4 http://marknelson.us/2010/09/12/innumeracy-revisited/ http://marknelson.us/2010/09/12/innumeracy-revisited/#comments Sun, 12 Sep 2010 17:35:39 +0000 Mark Nelson http://marknelson.us/2010/09/12/innumeracy-revisited/ The New York Times has an interesting article today examining the curious fact that certain types of terrorist organizations have an unusually high ratio of engineers among their members. An interesting point to study, no doubt, but what caught my eye was this little blunder: William A. Wulf, a former president of the National Academy [...]]]> http://marknelson.us/2010/09/12/innumeracy-revisited/feed/ 11 http://marknelson.us/2010/08/10/p-%e2%89%a0-np/ http://marknelson.us/2010/08/10/p-%e2%89%a0-np/#comments Tue, 10 Aug 2010 18:42:47 +0000 Mark Nelson http://marknelson.us/2010/08/10/p-%e2%89%a0-np/ You may have never heard of Vinay Deolalikar, but there is a chance that he may become next year’s Turing Award winner, not to mention an overnight millionaire. It seems that Vinay dropped the news at the start of this week that he had proven that P does not equal NP. In short, this proof [...]]]> http://marknelson.us/2010/08/10/p-%e2%89%a0-np/feed/ 0 http://marknelson.us/2010/08/06/5-trillion-digits-of-pi/ http://marknelson.us/2010/08/06/5-trillion-digits-of-pi/#comments Fri, 06 Aug 2010 18:46:27 +0000 Mark Nelson http://marknelson.us/2010/08/06/5-trillion-digits-of-pi/ Back in 1981, fresh out of school, I was awestruck by Steve Wozniak’s program that calculated over 100,000 digits of e on an Apple II. (Anyone who has a scan of his article in the June 1981 issue of Byte, please email me a copy!) Shortly after reading the article, I ported his program to [...]]]> http://marknelson.us/2010/08/06/5-trillion-digits-of-pi/feed/ 2 http://marknelson.us/2008/07/20/innumeracy-part-n/ http://marknelson.us/2008/07/20/innumeracy-part-n/#comments Sun, 20 Jul 2008 19:56:27 +0000 Mark Nelson http://marknelson.us/2008/07/20/innumeracy-part-n/ This isn’t the first time I’ve complained about innumeracy, and I’m sure it won’t be the last. Just to get off on the right foot, let me give the definition of the word from thesite innumeracy.com: A term meant to convey a person’s inability to make sense of the numbers that run their lives. Innumeracy [...]]]> http://marknelson.us/2008/07/20/innumeracy-part-n/feed/ 5 http://marknelson.us/1996/04/01/a-floating-point-problem/ http://marknelson.us/1996/04/01/a-floating-point-problem/#comments Mon, 01 Apr 1996 14:44:33 +0000 Mark Nelson http://test.kewby.com/?p=10 An example of how you can run into trouble when performing floating point comparisons.]]> http://marknelson.us/1996/04/01/a-floating-point-problem/feed/ 0