Matrix-class.RdThe Matrix class is a class contained by all actual
classes in the Matrix package. It is a “virtual” class.
Diman integer vector of length 2 giving the dimensions of the matrix.
Dimnamesa list of length 2. Each element must
be NULL or a character vector of length equal to the
corresponding element of Dim.
signature(x = "Matrix", logarithm = "missing"): and
signature(x = "Matrix", logarithm = "logical"):
compute the (\(\log\)) determinant of x. The method
chosen depends on the actual Matrix class of x. Note that
det also works for all our matrices, calling the
appropriate determinant() method. The Matrix::det
is an exact copy of base::det, but in the correct
namespace, and hence calling the S4-aware version of
determinant().).
signature(x = "Matrix"): As diff()
for traditional matrices, i.e., applying diff() to each
column.
signature(x = "Matrix"): extract matrix dimensions
dim.
signature(x = "Matrix", value = "ANY"): where
value is integer of length 2. Allows to reshape
Matrix objects, but only when prod(value) == prod(dim(x)).
signature(x = "Matrix"): extract
dimnames.
signature(x = "Matrix", value = "list"): set
the dimnames to a list of length 2, see
dimnames<-.
signature(x = "Matrix"): simply defined as
prod(dim(x)) (and hence of mode "double").
signature(object = "Matrix"): show
method for printing. For printing sparse
matrices, see printSpMatrix.
signature(x = "Matrix"): typically used for
"dMatrix": round() matrix entries
such that (relatively) very small entries become zero exactly.
signature(object = "Matrix"): draws an
image of the matrix entries, using
levelplot() from package lattice.
signature(object = "Matrix"): return only the
“head”, i.e., the first few rows.
signature(object = "Matrix"): return only the
“tail”, i.e., the last few rows of the respective matrix.
signature(x = "Matrix"): the same as
as(x, "matrix"); see also the note below.
signature(x = "Matrix", mode = "missing"):
as.vector(m) should be identical to as.vector(as(m,
"matrix")), implemented more efficiently for some subclasses.
etc, similarly.
signature(from = "ANY", to = "Matrix"): This
relies on a correct as.matrix() method for from.
There are many more methods that (conceptually should) work for all
"Matrix" objects, e.g., colSums,
rowMeans. Even base functions may work
automagically (if they first call as.matrix() on their
principal argument), e.g., apply, eigen,
svd or kappa all do work via coercion to a
“traditional” (dense) matrix.
Loading the Matrix namespace “overloads”
as.matrix and as.array in the base
namespace by the equivalent of function(x) as(x, "matrix").
Consequently, as.matrix(m) or as.array(m) will properly
work when m inherits from the "Matrix" class —
also for functions in package base and other packages.
E.g., apply or outer can therefore be applied
to "Matrix" matrices.
slotNames("Matrix")
#> [1] "Dim" "Dimnames"
cl <- getClass("Matrix")
names(cl@subclasses) # more than 40 ..
#> [1] "generalMatrix" "symmetricMatrix" "triangularMatrix" "nMatrix"
#> [5] "lMatrix" "iMatrix" "dMatrix" "zMatrix"
#> [9] "denseMatrix" "sparseMatrix" "ndenseMatrix" "ldenseMatrix"
#> [13] "ddenseMatrix" "unpackedMatrix" "packedMatrix" "ndenseMatrix"
#> [17] "ldenseMatrix" "ddenseMatrix" "CsparseMatrix" "RsparseMatrix"
#> [21] "TsparseMatrix" "diagonalMatrix" "nsparseMatrix" "lsparseMatrix"
#> [25] "dsparseMatrix" "ngeMatrix" "nsyMatrix" "ntrMatrix"
#> [29] "nspMatrix" "ntpMatrix" "lgeMatrix" "lsyMatrix"
#> [33] "ltrMatrix" "lspMatrix" "ltpMatrix" "dgeMatrix"
#> [37] "dsyMatrix" "dpoMatrix" "corMatrix" "dtrMatrix"
#> [41] "dspMatrix" "dppMatrix" "copMatrix" "dtpMatrix"
#> [45] "ngCMatrix" "nsCMatrix" "ntCMatrix" "ngRMatrix"
#> [49] "nsRMatrix" "ntRMatrix" "ngTMatrix" "nsTMatrix"
#> [53] "ntTMatrix" "ndiMatrix" "lgCMatrix" "lsCMatrix"
#> [57] "ltCMatrix" "lgRMatrix" "lsRMatrix" "ltRMatrix"
#> [61] "lgTMatrix" "lsTMatrix" "ltTMatrix" "ldiMatrix"
#> [65] "dgCMatrix" "dsCMatrix" "dtCMatrix" "dgRMatrix"
#> [69] "dsRMatrix" "dtRMatrix" "dgTMatrix" "dsTMatrix"
#> [73] "dtTMatrix" "ddiMatrix" "indMatrix" "pMatrix"
showClass("Matrix")#> output with slots and all subclasses
#> Virtual Class "Matrix" [package "Matrix"]
#>
#> Slots:
#>
#> Name: Dim Dimnames
#> Class: integer list
#>
#> Known Subclasses:
#> Class "generalMatrix", directly
#> Class "symmetricMatrix", directly
#> Class "triangularMatrix", directly
#> Class "nMatrix", directly
#> Class "lMatrix", directly
#> Class "iMatrix", directly
#> Class "dMatrix", directly
#> Class "zMatrix", directly
#> Class "denseMatrix", directly
#> Class "sparseMatrix", directly
#> Class "ndenseMatrix", by class "nMatrix", distance 2
#> Class "ldenseMatrix", by class "lMatrix", distance 2
#> Class "ddenseMatrix", by class "dMatrix", distance 2
#> Class "unpackedMatrix", by class "denseMatrix", distance 2
#> Class "packedMatrix", by class "denseMatrix", distance 2
#> Class "ndenseMatrix", by class "denseMatrix", distance 2
#> Class "ldenseMatrix", by class "denseMatrix", distance 2
#> Class "ddenseMatrix", by class "denseMatrix", distance 2
#> Class "CsparseMatrix", by class "sparseMatrix", distance 2
#> Class "RsparseMatrix", by class "sparseMatrix", distance 2
#> Class "TsparseMatrix", by class "sparseMatrix", distance 2
#> Class "diagonalMatrix", by class "sparseMatrix", distance 2
#> Class "nsparseMatrix", by class "nMatrix", distance 2
#> Class "lsparseMatrix", by class "lMatrix", distance 2
#> Class "dsparseMatrix", by class "dMatrix", distance 2
#> Class "ngeMatrix", by class "unpackedMatrix", distance 3
#> Class "nsyMatrix", by class "unpackedMatrix", distance 3
#> Class "ntrMatrix", by class "unpackedMatrix", distance 3
#> Class "nspMatrix", by class "packedMatrix", distance 3
#> Class "ntpMatrix", by class "packedMatrix", distance 3
#> Class "lgeMatrix", by class "unpackedMatrix", distance 3
#> Class "lsyMatrix", by class "unpackedMatrix", distance 3
#> Class "ltrMatrix", by class "unpackedMatrix", distance 3
#> Class "lspMatrix", by class "packedMatrix", distance 3
#> Class "ltpMatrix", by class "packedMatrix", distance 3
#> Class "dgeMatrix", by class "unpackedMatrix", distance 3
#> Class "dsyMatrix", by class "unpackedMatrix", distance 3
#> Class "dpoMatrix", by class "dsyMatrix", distance 3
#> Class "corMatrix", by class "dpoMatrix", distance 4
#> Class "dtrMatrix", by class "unpackedMatrix", distance 3
#> Class "dspMatrix", by class "packedMatrix", distance 3
#> Class "dppMatrix", by class "dspMatrix", distance 3
#> Class "copMatrix", by class "dppMatrix", distance 4
#> Class "dtpMatrix", by class "packedMatrix", distance 3
#> Class "ngCMatrix", by class "CsparseMatrix", distance 3
#> Class "nsCMatrix", by class "CsparseMatrix", distance 3
#> Class "ntCMatrix", by class "CsparseMatrix", distance 3
#> Class "ngRMatrix", by class "RsparseMatrix", distance 3
#> Class "nsRMatrix", by class "RsparseMatrix", distance 3
#> Class "ntRMatrix", by class "RsparseMatrix", distance 3
#> Class "ngTMatrix", by class "TsparseMatrix", distance 3
#> Class "nsTMatrix", by class "TsparseMatrix", distance 3
#> Class "ntTMatrix", by class "TsparseMatrix", distance 3
#> Class "ndiMatrix", by class "diagonalMatrix", distance 3
#> Class "lgCMatrix", by class "CsparseMatrix", distance 3
#> Class "lsCMatrix", by class "CsparseMatrix", distance 3
#> Class "ltCMatrix", by class "CsparseMatrix", distance 3
#> Class "lgRMatrix", by class "RsparseMatrix", distance 3
#> Class "lsRMatrix", by class "RsparseMatrix", distance 3
#> Class "ltRMatrix", by class "RsparseMatrix", distance 3
#> Class "lgTMatrix", by class "TsparseMatrix", distance 3
#> Class "lsTMatrix", by class "TsparseMatrix", distance 3
#> Class "ltTMatrix", by class "TsparseMatrix", distance 3
#> Class "ldiMatrix", by class "diagonalMatrix", distance 3
#> Class "dgCMatrix", by class "CsparseMatrix", distance 3
#> Class "dsCMatrix", by class "CsparseMatrix", distance 3
#> Class "dtCMatrix", by class "CsparseMatrix", distance 3
#> Class "dgRMatrix", by class "RsparseMatrix", distance 3
#> Class "dsRMatrix", by class "RsparseMatrix", distance 3
#> Class "dtRMatrix", by class "RsparseMatrix", distance 3
#> Class "dgTMatrix", by class "TsparseMatrix", distance 3
#> Class "dsTMatrix", by class "TsparseMatrix", distance 3
#> Class "dtTMatrix", by class "TsparseMatrix", distance 3
#> Class "ddiMatrix", by class "diagonalMatrix", distance 3
#> Class "indMatrix", by class "sparseMatrix", distance 2
#> Class "pMatrix", by class "indMatrix", distance 3
(M <- Matrix(c(0,1,0,0), 6, 4))
#> 6 x 4 sparse Matrix of class "dgCMatrix"
#>
#> [1,] . . . .
#> [2,] 1 . 1 .
#> [3,] . . . .
#> [4,] . 1 . 1
#> [5,] . . . .
#> [6,] 1 . 1 .
dim(M)
#> [1] 6 4
diag(M)
#> [1] 0 0 0 1
cm <- M[1:4,] + 10*Diagonal(4)
diff(M)
#> 5 x 4 sparse Matrix of class "dgCMatrix"
#>
#> [1,] 1 . 1 .
#> [2,] -1 . -1 .
#> [3,] . 1 . 1
#> [4,] . -1 . -1
#> [5,] 1 . 1 .
## can reshape it even :
dim(M) <- c(2, 12)
M
#> 2 x 12 sparse Matrix of class "dgCMatrix"
#>
#> [1,] . . . . . . . . . . . .
#> [2,] 1 . 1 . 1 . 1 . 1 . 1 .
stopifnot(identical(M, Matrix(c(0,1,0,0), 2,12)),
all.equal(det(cm),
determinant(as(cm,"matrix"), log=FALSE)$modulus,
check.attributes=FALSE))