R help - Jul 2012 - Creating sparse matrix of type "dgCMatrix" directly

I want to create a sparse matrix of type "dgCMatrix" using the Matrix
package (and the matrix must be of this type even if other more compact
representations may exist). I do
> library(Matrix)
> m1<-Matrix(rep(1,4),nrow=2,ncol=2,sparse=T)
> m1
2 x 2 sparse Matrix of class "dsCMatrix"
        
[1,] 1 1
[2,] 1 1

To convert m1, I do
> as(m1, "dgCMatrix")
2 x 2 sparse Matrix of class "dgCMatrix"
        
[1,] 1 1
[2,] 1 1

Is it possible to construct a dgCMatrix "directly" i.e. without going
through the additional as() step above?

Best regards
S?ren

On Sat, Jul 28, 2012 at 7:26 AM, S?ren H?jsgaard <sorenh at math.aau.dk>
wrote:
> I want to create a sparse matrix of type "dgCMatrix" using the
Matrix package (and the matrix must be of this type even if other more compact
representations may exist). I do
>
>> library(Matrix)
>> m1<-Matrix(rep(1,4),nrow=2,ncol=2,sparse=T)
>> m1
> 2 x 2 sparse Matrix of class "dsCMatrix"
>
> [1,] 1 1
> [2,] 1 1
>
> To convert m1, I do
>> as(m1, "dgCMatrix")
> 2 x 2 sparse Matrix of class "dgCMatrix"
>
> [1,] 1 1
> [2,] 1 1
>
> Is it possible to construct a dgCMatrix "directly" i.e. without
going through the additional as() step above?
The Matrix function is a high-level function that is designed to
produce a compact and informative representation of its arguments.
That's why it checks for symmetry, triangularity, etc.

To decide how to bypass these checks it would be useful to know what
you are starting with.  Will it be a dense matrix or a triplet
representation or ...?