be careful D^0 is not the zeroeth power of a matrix. It is a term power :D[i,j]^0=1
To obtain the power of a matrix, you can use a decomposition such as svd:
X = U D V' the n-th power of X is X = U D^n V'
svd1=svd(D) Apower0=svd1$u%*%diag(svd1$d^0)%*%t(svd1$v)
At 11:40 20/01/2004, Federico Calboli wrote:
Dear All,
I would like to ask why the zeroeth power of a matrix gives me a matrix of ones rather than the identity matrix:
> D<-rbind(c(0,0,0),c(0,0,0),c(0,0,0)) > D<-as.matrix(D) > D [,1] [,2] [,3] [1,] 0 0 0 [2,] 0 0 0 [3,] 0 0 0
> D^0 [,1] [,2] [,3] [1,] 1 1 1 [2,] 1 1 1 [3,] 1 1 1
I would have expected the identity matrix here.
I find the same result with every other square matrix I used. BTW, I am using R 1.8.1 on Linux Mandrake 9.1
Cheers,
Federico Calboli --
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Federico C. F. Calboli
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