Memory Efficiency of Symmetric Matrix

the SparseM package might be what you are looking for

http://www.econ.uiuc.edu/~roger/research/sparse/SparseM.pdf
You can do
mat[lower.tri(mat, diag=F)]
S?ren

________________________________

Fra: r-help-boun... at r-project.org p? vegne af Nathan S. Watson-Haigh
Sendt: on 07-01-2009 01:28
Til: r-h... at r-project.org
Emne: [R] Memory Efficiency of Symmetric Matrix

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I'm generating a symmetric correlation matrix using a data matrix as input:
mat <- cor(data.mat)

My question is:
Is there a more memory efficient way to store this data? For instance, since:
all(mat == t(mat))
every value is duplicated, and I should be able to almost half the memory usage for large matrices.

Any thoughts/comments?

Cheers,
Nathan

- --
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Dr. Nathan S. Watson-Haigh
OCE Post Doctoral Fellow
CSIRO Livestock Industries
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Australia

Tel: +61 (0)7 3214 2922
Fax: +61 (0)7 3214 2900
Web:http://www.csiro.au/people/Nathan.Watson-Haigh.html
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Memory Efficiency of Symmetric Matrix

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