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Topic: Solving sparse Ax=b without certain eigenvector spaces
Replies: 11   Last Post: Aug 8, 2014 3:25 AM

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 Hui Posts: 5 Registered: 8/2/14
Solving sparse Ax=b without certain eigenvector spaces
Posted: Aug 2, 2014 6:13 PM

Hi, I'm trying to solve a sparse Ax=b problem. The size of A is about 10^4 by 10^4. A is pretty singular and the first a few eigenvalues of A is about 10^(-12), 10^(-6) and 10^(-4). I'm able to find the first a few eigenvalues and eigenvectors using the command eigs, which takes only one or two seconds. Now I want to find x, such that Ax=b, but I want to exclude the first three eigenvectors.

Are there any simple ways that allow me to do this?

Date Subject Author
8/2/14 Hui
8/2/14 John D'Errico
8/3/14 Hui
8/3/14 Bruno Luong
8/3/14 Bruno Luong
8/3/14 Hui
8/4/14 Bruno Luong
8/7/14 Hui
8/8/14 Bruno Luong
8/3/14 John D'Errico
8/3/14 Hui
8/4/14 Bruno Luong