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Re: conditon of a matrix
Posted:
Mar 28, 2011 10:53 PM


Hi Greg,
You are correct. In fact,
(1) pinv(K)*F will give the minimum norm solution
(2) K \ F will give the solution vector x that has the minimum number of nonzero elements.
I learned about these 2 solutions from Mr. Cleve Moler's article "The world smallest impossible problem". I think you can get it in Mathworks website. Very good article.
Kevin
Greg Heath <heath@alumni.brown.edu> wrote in message <5b7127025957440f95a4810f3660878e@h38g2000yqn.googlegroups.com>... > On Mar 28, 11:23 am, "Kevin" <kh...@fake.com> wrote: > > There is another option. If for whatever reason, you don't like the solution from "K\F", then try this > > > > pinv(K)*F. > > > > I believe this will give you a different answer for x but the residual error would still be small. In this case the vector x contains the minimum number of nonzero entries. > > On the contrary. In order to obtain the minimum norm > solution, all elements must be nonzero. > > On the other hand, the backslash solution will tend to have > the maximum number of zero elements. > > Hope this helps. > > Greg



