Matrix (version 1.7-6)

dsyMatrix-class: Symmetric Dense (Packed or Unpacked) Numeric Matrices

Description

• The "dsyMatrix" class is the class of symmetric, dense matrices in non-packed storage and

• "dspMatrix" is the class of symmetric dense matrices in packed storage, see pack(). Only the upper triangle or the lower triangle is stored.

See Also

The positive (Semi-)definite dense (packed or non-packed numeric matrix classes dpoMatrix, dppMatrix and corMatrix,

Classes dgeMatrix and Matrix; solve, norm, rcond, t

Examples

 
library(utils, pos = "package:base", verbose = FALSE)

## Only upper triangular part matters (when uplo == "U" as per default)
(sy2 <- new("dsyMatrix", Dim = as.integer(c(2,2)), x = c(14, NA,32,77)))
str(t(sy2)) # uplo = "L", and the lower tri. (i.e. NA is replaced).

chol(sy2) #-> "Cholesky" matrix
(sp2 <- pack(sy2)) # a "dspMatrix"

## Coercing to dpoMatrix gives invalid object:
sy3 <- new("dsyMatrix", Dim = as.integer(c(2,2)), x = c(14, -1, 2, -7))
try(as(sy3, "dpoMatrix")) # -> error: not positive definite
# \dontshow{
tr <- try(as(sy3, "dpoMatrix"), silent=TRUE)
stopifnot(1 == grep("not a positive definite matrix",
                    as.character(tr)),
	  is(sp2, "dspMatrix"))
# }

## 4x4 example
m <- matrix(0,4,4); m[upper.tri(m)] <- 1:6
(sym <- m+t(m)+diag(11:14, 4))
(S1 <- pack(sym))
(S2 <- t(S1))
stopifnot(all(S1 == S2)) # equal "seen as matrix", but differ internally :
str(S1)
S2@x