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Subject: Indexing into large sparse matrix From: NIcholas Date: 24 Mar, 2009 20:44:02 Message: 1 of 9 
I have a large sparse matrix with number of elements exceeding the maximum variable size allowed in matlab (though number of rows and columns do not) e.g. A = sparse([],[],[],10e6,10e6,0)) 
"NIcholas" <remove.this_nmg33@cornell.edu> wrote in message <gqbgmi$ll6$1@fred.mathworks.com>... 
Subject: Indexing into large sparse matrix From: Bruno Luong Date: 24 Mar, 2009 22:10:05 Message: 3 of 9 
"NIcholas" <remove.this_nmg33@cornell.edu> wrote in message <gqbgmi$ll6$1@fred.mathworks.com>... 
Subject: Indexing into large sparse matrix From: Bruno Luong Date: 24 Mar, 2009 22:17:01 Message: 4 of 9 
Sorry, the second error message should be: 
Subject: Indexing into large sparse matrix From: NIcholas Date: 24 Mar, 2009 22:32:01 Message: 5 of 9 
The application is a "sparse image" filtering. I have a large set of grid points with weights (intensities) and I am trying to filter this image with a gaussian and I am only interested in the value at nonzero locations in the original image  this arose as a discretization of a Kernel Density Estimation where I am only interested in the value of the PDF at the sample points  I was trying to make this quicker than O(N^2) and using a discrete grid makes it O(N*K) where K is the number of nonzero elements in the (truncated) Gaussian kernel. 
"NIcholas" <remove.this_nmg33@cornell.edu> wrote in message <gqbn11$9c2$1@fred.mathworks.com>... 
"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <gqblnt$7c7$1@fred.mathworks.com>... 
Subject: Indexing into large sparse matrix From: Bruno Luong Date: 24 Mar, 2009 22:55:18 Message: 8 of 9 
"Matt " <xys@whatever.com> wrote in message <gqbnv1$b9q$1@fred.mathworks.com>... 
"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <gqbocm$a1e$1@fred.mathworks.com>... 
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