Matrix {Matrix}  R Documentation 
Construct a Matrix of a class that inherits from Matrix
.
Matrix(data=NA, nrow=1, ncol=1, byrow=FALSE, dimnames=NULL, sparse = NULL, doDiag = TRUE, forceCheck = FALSE)
data 
an optional numeric data vector or matrix. 
nrow 
when 
ncol 
when 
byrow 
logical. If 
dimnames 
a 
sparse 
logical or Note that when the resulting matrix is diagonal (“mathematically”),

doDiag 
only when 
forceCheck 
logical indicating if the checks for structure
should even happen when 
If either of nrow
or ncol
is not given, an attempt is
made to infer it from the length of data
and the other
parameter.
Further, Matrix()
makes efforts to keep logical
matrices logical, i.e., inheriting from class lMatrix
,
and to determine specially structured matrices such as symmetric,
triangular or diagonal ones. Note that a symmetric matrix also
needs symmetric dimnames
, e.g., by specifying
dimnames = list(NULL,NULL)
, see the examples.
Most of the time, the function works via a traditional (full)
matrix
. However, Matrix(0, nrow,ncol)
directly
constructs an “empty” sparseMatrix, as does
Matrix(FALSE, *)
.
Although it is sometime possible to mix unclassed matrices (created
with matrix
) with ones of class "Matrix"
, it is much
safer to always use carefully constructed ones of class
"Matrix"
.
Returns matrix of a class that inherits from "Matrix"
.
Only if data
is not a matrix
and does not already inherit
from class Matrix
are the arguments
nrow
, ncol
and byrow
made use of.
The classes Matrix
,
symmetricMatrix
,
triangularMatrix
, and
diagonalMatrix
; further,
matrix
.
Special matrices can be constructed, e.g., via
sparseMatrix
(sparse), bdiag
(blockdiagonal), bandSparse
(banded sparse), or
Diagonal
.
Matrix(0, 3, 2) # 3 by 2 matrix of zeros > sparse Matrix(0, 3, 2, sparse=FALSE)# > 'dense' Matrix(0, 2, 2, sparse=FALSE)# diagonal ! Matrix(0, 2, 2, sparse=FALSE, doDiag=FALSE)# > dense Matrix(1:6, 3, 2) # a 3 by 2 matrix (+ integer warning) Matrix(1:6 + 1, nrow=3) ## logical ones: Matrix(diag(4) > 0)# > "ldiMatrix" with diag = "U" Matrix(diag(4) > 0, sparse=TRUE)# > sparse... Matrix(diag(4) >= 0)# > "lsyMatrix" (of all 'TRUE') ## triangular l3 < upper.tri(matrix(,3,3)) (M < Matrix(l3)) # > "ltCMatrix" Matrix(! l3)# > "ltrMatrix" as(l3, "CsparseMatrix") Matrix(1:9, nrow=3, dimnames = list(c("a", "b", "c"), c("A", "B", "C"))) (I3 < Matrix(diag(3)))# identity, i.e., unit "diagonalMatrix" str(I3) # note the empty 'x' slot (A < cbind(a=c(2,1), b=1:2))# symmetric *apart* from dimnames Matrix(A) # hence 'dgeMatrix' (As < Matrix(A, dimnames = list(NULL,NULL)))# > symmetric stopifnot(is(As, "symmetricMatrix"), is(Matrix(0, 3,3), "sparseMatrix"), is(Matrix(FALSE, 1,1), "sparseMatrix"))