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Aug 23, 2013 at 16:52 answer added Michael timeline score: 0
Aug 23, 2013 at 15:21 answer added karakfa timeline score: 0
Mar 21, 2011 at 15:06 comment added Charles Staats Have you thought of asking this question on StackOverflow? They might be a better resource if you are interested in practical computation.
Mar 21, 2011 at 14:09 answer added Brian Borchers timeline score: 6
Mar 21, 2011 at 14:03 answer added Aaron Meyerowitz timeline score: 1
Mar 21, 2011 at 12:53 comment added Steve Huntsman mathoverflow.net/questions/8863/…
Mar 21, 2011 at 9:30 comment added Nancy Yeah, you can alteratively think of this problem as solve a linear equation in terms of $Y$ such that $(E-aX)Y=E$.
Mar 21, 2011 at 6:52 comment added Gerry Myerson @Nancy, I think what Thierry is saying is that what's efficient in theory may not be efficient in practice, and vice versa. Also, what's efficient when $n=10$ may not be when $n=10,000$, and also the answer may depend on just how sparse is sparse.
Mar 21, 2011 at 6:50 comment added Henry Cohn There's also the question of whether you really want the inverse matrix. (For example, if you are trying to solve a system of linear equations, then computing the inverse is not the best approach.) The matrix $E-aX$ is diagonally dominant, which is an important hypothesis for analyzing iterative algorithms, such as the Jacobi method for solving systems of equations.
Mar 21, 2011 at 6:47 comment added Nancy I am just wondering whether there would be some effciient way to optimize the ${E-a \cdot X}^{-1}$ computation?
Mar 21, 2011 at 6:40 history edited Nancy CC BY-SA 2.5
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Mar 21, 2011 at 6:21 comment added Thierry Zell What are you looking for? Good theoretical complexity or fast answer in practice? These are two different questions.
Mar 21, 2011 at 6:04 history edited S. Carnahan CC BY-SA 2.5
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Mar 21, 2011 at 5:56 history asked Nancy CC BY-SA 2.5