Symmetric Dense Nonzero-Pattern Matrices

The "nsyMatrix" class is the class of symmetric, dense nonzero-pattern matrices in non-packed storage and "nspMatrix" is the class of of these in packed storage. Only the upper triangle or the lower triangle is stored.

Objects from the Class

Objects can be created by calls of the form new("nsyMatrix", ...).

Slots

uplo:

Object of class "character". Must be either "U", for upper triangular, and "L", for lower triangular.

x:

Object of class "logical". The logical values that constitute the matrix, stored in column-major order.

Dim,Dimnames:

The dimension (a length-2 "integer") and corresponding names (or NULL), see the Matrix class.

factors:

Object of class "list". A named list of factorizations that have been computed for the matrix.

Extends

"nsyMatrix" extends class "ngeMatrix", directly, whereas
"nspMatrix" extends class "ndenseMatrix", directly.

Both extend class "symmetricMatrix", directly, and class "Matrix" and others, indirectly, use showClass("nsyMatrix"), e.g., for details.

Methods

Currently, mainly t() and coercion methods (for as(.); use, e.g., showMethods(class="nsyMatrix") for details.

See also

ngeMatrix, Matrix, t

Examples

(s0 <- new("nsyMatrix"))
#> 0 x 0 Matrix of class "nsyMatrix"
#> <0 x 0 matrix>

(M2 <- Matrix(c(TRUE, NA, FALSE, FALSE), 2, 2)) # logical dense (ltr)
#> 2 x 2 Matrix of class "ltrMatrix"
#>       [,1]  [,2]
#> [1,]  TRUE     .
#> [2,]    NA FALSE
(sM <- M2 & t(M2))                       # -> "lge"
#> 2 x 2 Matrix of class "lgeMatrix"
#>       [,1]  [,2]
#> [1,]  TRUE FALSE
#> [2,] FALSE FALSE
class(sM <- as(sM, "nMatrix"))           # -> "nge"
#> [1] "ngeMatrix"
#> attr(,"package")
#> [1] "Matrix"
     (sM <- as(sM, "symmetricMatrix"))   # -> "nsy"
#> 2 x 2 Matrix of class "nsyMatrix"
#>       [,1]  [,2]
#> [1,]  TRUE FALSE
#> [2,] FALSE FALSE
str(sM <- as(sM, "packedMatrix")) # -> "nsp", i.e., packed symmetric
#> Formal class 'nspMatrix' [package "Matrix"] with 5 slots
#>   ..@ uplo    : chr "U"
#>   ..@ Dim     : int [1:2] 2 2
#>   ..@ Dimnames:List of 2
#>   .. ..$ : NULL
#>   .. ..$ : NULL
#>   ..@ x       : logi [1:3] TRUE FALSE FALSE
#>   ..@ factors : list()