This function will create an identitiy matrix, in the sparse
bdsmatrix format.
Usage
bdsI(id, blocksize)
Value
an identity matrix.
Arguments
id
the identifier list.
This will become the dimnames of the final matrix, and must be a
set of unique values.
It's length determines the dimension of the final matrix
blocksize
the blocksize vector of the final matrix.
If supplied, the sum of blocksizes must equal the dimension of the matrix.
By default, the created matrix is as sparse as possible.