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   -> Volume 3, Issue 12


Question: Matrix Compression
 
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wvl@ipp-garching.mpg.de (Wolfgang von der Linden)
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PostPosted: Mon Dec 02, 2002 1:17 pm    
Subject: Question: Matrix Compression
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Question: Matrix Compression

Dear Colleagues,

is there anybody around, who knows how to compress
a matrix of the form

M_{ij} = e^{a * ((x_i-x_j)^2 + (y_i-y_j)^2)}

using discrete wavelet transform.
Where (x_i,y_i) are point on a 2d square lattice,
e.g.
x_i = mod(i,256)
y_i = integer(i/256)

The approach, given in Numerical Recipes, gives
merely a compression by 50% if one discards matrix elements
of size 10^{-6}, which is worse than the original
matrix and in disagreement to W.Press's statement
that the number of matrix elements, larger than eps, is
10*N*Log_{10}(eps)


Thanks


Wolfgang von der Linden

My e-mail address reads (wvl@ibmop5.ipp-garching.mpg.de)
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