Sunday, May 01, 2005

π may be irrational, but it's not that random ..

I'm not feeling very mathematical, today.

I found this article through Slashdot, and thought it was somewhat mathematically interesting. Apparently there are better ways to procure random numbers than to choose from a table of digits of π.

Oddly enough, the discovery was made by physicists, not mathematicians or even statisticians. Go figure.

WEST LAFAYETTE, Ind. – If you wanted a random number, historically you could do worse than to pick a sequence from the string of digits in pi. But Purdue University scientists now say other sources might be better.

Physicists including Purdue's Ephraim Fischbach have completed a study comparing the "randomness" in pi to that produced by 30 software random number generators and one chaos-generating physical machine. After conducting several tests, they have found that while sequences of digits from pi are indeed an acceptable source of randomness – often an important factor in data encryption and in solving certain physics problems – pi's digit string does not always produce randomness as effectively as manufactured generators do.

"We do not believe these results imply anything about a pattern existing in pi's number set," said Fischbach, who is a professor of physics in Purdue's College of Science. "However, it may imply that if your livelihood depends on a reliable source of random numbers, as a cryptographer's might, then some commercially available random number generators might serve you better."

More of the article can be found here.

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