Group JGD_Trefethen
Group Description |
Diagonal matrices with primes, Nick Trefethen, Oxford Univ. From Jean-Guillaume Dumas' Sparse Integer Matrix Collection, http://ljk.imag.fr/membres/Jean-Guillaume.Dumas/simc.html Problem 7 of the Hundred-dollar, Hundred-digit Challenge Problems, SIAM News, vol 35, no. 1. 7. Let A be the 20,000 x 20,000 matrix whose entries are zero everywhere except for the primes 2, 3, 5, 7, . . . , 224737 along the main diagonal and the number 1 in all the positions A(i,j) with |i-j| = 1,2,4,8, . . . ,16384. What is the (1,1) entry of inv(A)? http://www.siam.org/news/news.php?id=388 |
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