[R] Creating a Sparse Matrix from a Sparse Vector

[BDGrantham at Hormel.com]

Hello,

I am working with a sparse matrix that is approx. 13,900 by 14,100.  My
goal is to select a row out of the matrix and create a new matrix with that
row repeated 13,900 times without having to do any looping.  Example:

Starting Matrix:

exampleMatrix
3 x 4 sparse Matrix of class "dgCMatrix"

[1,] 1 . . .
[2,] . 1 . 0.5
[3,] . . 1 ..

New Matrix:..

 newExampleMatrix
3 x 4 sparse Matrix of class "dgCMatrix"

[1,] . 1 . 0.5
[2,] . 1 . 0.5
[3,] . 1 . 0.5

When I try the following I get a memory allocation error due to the size of
the array or vector:

 newExampleMatrix<-Matrix(rep(exampleMatrix[2,],times=nrow
(exampleMatrix)),nrow=nrow(exampleMatrix),ncol=ncol
(exampleMatrix),byrow=TRUE,sparse=TRUE)
 newExampleMatrix<-Matrix(exampleMatrix[2,],nrow=nrow
(exampleMatrix),ncol=ncol(exampleMatrix),byrow=TRUE,sparse=TRUE)

When I tried the next set, I got the error "Error in Matrix(as(rep
(exampleMatrix[2, ], times = nrow(exampleMatrix)),  :   invalid type/length
(S4/12) in vector allocation":

newExampleMatrix<-Matrix(as(rep(exampleMatrix[2,],times=nrow
(exampleMatrix)),"sparseVector"),nrow=nrow(exampleMatrix),ncol=ncol
(exampleMatrix),byrow=TRUE,sparse=TRUE)
newExampleMatrix<-Matrix(as(exampleMatrix[2,],"sparseVector"),nrow=nrow
(exampleMatrix),ncol=ncol(exampleMatrix),byrow=TRUE,sparse=TRUE)

And finally, when I tried the next instruction, I got the error "Error in
as.vector(x, mode) :  cannot coerce type 'S4' to vector of type 'any' Error
in as.matrix.csc(as.matrix.csr(x)) : error in evaluating the argument 'x'
in selecting a method for function 'as.matrix.csc'" :

as.matrix.csc(as(rep(currentMatrix[pivitRow,],times=nrow
(currentMatrix)),"sparseVector"),nrow=nrow(currentMatrix),ncol=ncol
(currentMatrix))

Are there any other ways to accomplish this?],

Thanks,

Brian




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