[R] NA's?

[Mulholland, Tom]

See upper.tri and lower.tri.

I think that you might also look for specific packages that function using matrices, from what I have seen these often have the capacity to ignore the diagonal or use just the upper or lower triangle. This is not an area that I use very much, but I have seen various posts about different types of matrices and there appears to be quite a lot of code that deals with the range of types and uses. Obvious candidates include the Matrix package, but a search for matrix in all of the CRAN packages brings up a bewildering variety of matrix related functions. You may find it useful to search for the specific type of manipulation that you are attempting.

Tom

> -----Original Message-----
> From: Asha Jayanthi [mailto:ashajayanthi at hotmail.com]
> Sent: Thursday, 31 March 2005 9:22 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] NA's?
> 
> 
> I have a large matrix of data .
> 
> The size of the matrix ranges from 100 x 100 to 1000 x 1000
> 
> Now i have to do computations on that. And should not 
> consider the diagonal 
> elements.
> 
> I tried setting diag(M) = NA  and M = na.omit(M).
> 
> But this omits all the rows. I only want to omit that 
> diagonal elements only 
> but consider the whole row.
> 
> diag(M) = 0 seems like a good option but this will affect my result.
> 
> How to proceed with this. How to just ignore some specific 
> values. what if i 
> want to consider only the upper / lower triangular matrix
> 
> Asha
> 
> 
> http://adfarm.mediaplex.com/ad/ck/4686-26272-10936-31?ck=RegSe
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