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No Magic In A Knight's Tour
morgothan writes "As reported in an article on Math World the solution, or rather lack of solution has been found to the over one hundred fifty year old math problem of how many numbers of magic tours a knight can make on a standard 8x8 chessboard. It turn out that there exist one hundred forty distinct semimagic tours, but no magic tour. The solution came after 61.40 CPU-days, corresponding to 138.25 days of computation at 1 GHz, the project was completed on August 5, 2003 in which every possible enumeration was tried out. The author of the software that finally solved the problem has also put up a webpage in which he further explains the problem and his method of solving it." Thanks to Mig for pointing out a great background page on Chessbase.com.
Now we're going to examine how many routes there are through all the bars in Amsterdam, and see if there are any "magic" routes that will let us complete the circuit without falling drunk in a bed of tulips.
Sheesh, evil *and* a jerk. -- Jade
Nope, but they got through about six coconuts.
"Nah. A result is a result no matter what methods were used to produce it. No cheating."
I spy an Nvidia engineer!
The solution came after 61.40 CPU-days, corresponding to 138.25 days of computation at 1 GHz
Yeah, and I came to work in 12.34 horsepower-hours, corresponding to 666.13 hours of driving at 5K RPM. I mean, damn, I understand when my mom utters movie-level technobabble, but this?
Oh please. Next you'll want to know the exact DRAM configuration. Was it DDR? How big was the L2? Was the data set swapped out to a 7200rpm hard disk or a 10k rpm disk?
Good grief. It's just an estimate. It's not the exact compute time that's interesting. It still tells me the interesting bits-- that it was a complexity that an ordinary PC could do in a reasonable time frame, not the sort of thing a gigantic cluster chewed on for 100 years.
Sir Paul McCartney did make a Magical Mystery Tour