[R] Memory Efficiency of Symmetric Matrix

[Søren Højsgaard]

You can do
mat[lower.tri(mat, diag=F)]
Søren

 
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Fra: r-help-bounces at r-project.org på vegne af Nathan S. Watson-Haigh
Sendt: on 07-01-2009 01:28
Til: r-help 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
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CSIRO Livestock Industries
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Tel: +61 (0)7 3214 2922
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