Symmetric, compressed, sparse column matrices

Description

The dsCMatrix class is a class of symmetric, sparse 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 a class of symmetric, sparse matrices in triplet format.

Objects from the Class

Objects can be created by calls of the form new("dsCMatrix", ...) or new("dsTMatrix", ...)

Slots

uplo:

A character object indicating if the upper triangle ("U" or "u") or the lower triangle ("L" or "l") is stored. At present only the lower triangle form is allowed.

p:

Object of class "integer" of pointers, one for each column, to the initial (zero-based) index of elements in the column. (Only present in the dsCMatrix class.)

i:

Object of class "integer" of length nnzero (number of non-zero elements). These are the row numbers for each non-zero element in the matrix.

j:

Object of class "integer" of length nnzero (number of non-zero elements). These are the column numbers for each non-zero element in the matrix. (Only present in the dsTMatrix class.)

x:

Object of class "numeric" - the non-zero elements of the matrix.

factors:

Object of class "list" - a list of factorizations of the matrix.

Dim:

Object of class "integer" - the dimensions of the matrix - must be an integer vector with exactly two non-negative values.

Extends

Class "dgCMatrix", directly.

Methods

solve

signature(a = "dsCMatrix", b = "matrix"): Solve a linear system of equations defined by x using a Cholesky decomposition.

chol

signature(x = "dsCMatrix", pivot = "logical"): Returns (and stores) the Cholesky decomposition of the matrix x. If pivot is TRUE (the default) Metis is used to create a reordering of the rows and columns of x so as to minimize fill-in.

determinant

signature(x = "dsCMatrix", logarithm = "missing"): Evaluate the determinant of x on the logarithm scale. This creates and stores the Cholesky factorization.

determinant

signature(x = "dsCMatrix", logarithm = "logical"): Evaluate the determinant of x on the logarithm scale or not, according to the logarithm argument. This creates and stores the Cholesky factorization.

t

signature(x = "dsCMatrix"): Transpose. Because x is symmetric this has no effect.

t

signature(x = "dsTMatrix"): Transpose. For the dsTMatrix class the row and column indices are interchanged so that a matrix for which the upper triangle is stored produces a matrix for which the lower triangle is stored and vice versa.

coerce

signature(from = "dsCMatrix", to = "dgTMatrix")

coerce

signature(from = "dsCMatrix", to = "dgeMatrix")

coerce

signature(from = "dsCMatrix", to = "matrix")

coerce

signature(from = "dsTMatrix", to = "dgeMatrix")

coerce

signature(from = "dsTMatrix", to = "dsCMatrix")

coerce

signature(from = "dsTMatrix", to = "dsyMatrix")

coerce

signature(from = "dsTMatrix", to = "matrix")

See Also

dgCMatrix-class, dgTMatrix-class, dgeMatrix-class