Matrix (version 1.2-1)

dsCMatrix-class: Numeric Symmetric Sparse (column compressed) Matrices

Description

The dsCMatrix class is a class of symmetric, sparse numeric matrices in the compressed, column-oriented format. In this implementation the non-zero elements in the columns are sorted into increasing row order.

The dsTMatrix class is the class of symmetric, sparse numeric matrices in triplet format.

Objects from the Class

Objects can be created by calls of the form new("dsCMatrix", ...) or new("dsTMatrix", ...), or automatically via e.g., as(*, "symmetricMatrix"), or (for dsCMatrix) also from Matrix(.).

Creation from scratch most efficiently happens via sparseMatrix(*, symmetric=TRUE).

Extends

Both classes extend classes and symmetricMatrix dsparseMatrix directly; dsCMatrix further directly extends CsparseMatrix, where dsTMatrix does TsparseMatrix.

See Also

Classes dgCMatrix, dgTMatrix, dgeMatrix and those mentioned above.

Examples

mm <- Matrix(toeplitz(c(10, 0, 1, 0, 3)), sparse = TRUE)
mm # automatically dsCMatrix
str(mm)

## how would we go from a manually constructed Tsparse* :
mT <- as(mm, "dgTMatrix")

## Either
(symM <- as(mT, "symmetricMatrix"))# dsT
(symC <- as(symM, "CsparseMatrix"))# dsC
## or
sC <- Matrix(mT, sparse=TRUE, forceCheck=TRUE)

sym2 <- as(symC, "TsparseMatrix")
## --> the same as 'symM', a "dsTMatrix"
stopifnot(identical(symC, sC), identical(sym2, symM),
          class(sym2) == "dsTMatrix",
	  identical(sym2[1,], sC[1,]),
	  identical(sym2[,2], sC[,2]))