dgTMatrix-class {Matrix} | R Documentation |
The "dgTMatrix"
class is the class of sparse
matrices stored as (possibly redundant) triplets. The internal
representation is not at all unique, contrary to the one for class
dgCMatrix
.
Objects can be created by calls of the form new("dgTMatrix",
...)
, but more typically via as(*, "dgTMatrix")
.
i
:"integer"
- the row indices
of non-zero entries in 0-base, i.e., must be in
0:(nrow(.)-1)
.j
:"integer"
- the column
indices of non-zero entries. Must be the same length as slot
i
and 0-based as well, i.e., in 0:(ncol(.)-1)
.x
:"numeric"
- the (non-zero)
entry at position (i,j)
. Must be the same length as slot
i
. If an index pair occurs more than once the corresponding
values of slot x
are added to form the element of the matrix.Dim
:"integer"
of length 2 -
the dimensions of the matrix.signature(e1 = "dgTMatrix", e2 = "dgTMatrix")
signature(from = "dgTMatrix", to = "dgCMatrix")
signature(from = "dgTMatrix", to = "dgeMatrix")
signature(from = "dgTMatrix", to = "matrix")
signature(from = "dgTMatrix", to = "dsCMatrix")
signature(from = "matrix", to = "dsTMatrix")
signature(x = "dgTMatrix", y = "missing")
returns t(x) %*% x
as an dsCMatrix
object.signature(x = "dgTMatrix", y = "matrix")
: ... signature(x = "dgTMatrix", y = "numeric")
: ... signature(x = "dgTMatrix")
: plots an image of
x
using the levelplot
functionsignature(x = "dgTMatrix")
: returns the transpose of
x
Triplet matrices are a convenient form in which to construct sparse
matrices after which they can be coerced to
dgCMatrix
objects.
Class dgCMatrix
or the superclasses
dsparseMatrix
and
TsparseMatrix
.
m <- Matrix(0+1:28, nrow = 4) m[-3,c(2,4:5,7)] <- m[ 3, 1:4] <- m[1:3, 6] <- 0 (mT <- as(m, "dgTMatrix")) str(mT) mT[1,] mT[4, drop = FALSE]