| symmpart {Matrix} | R Documentation |
symmpart(x) computes the symmetric part (x + t(x))/2 and
skewpart(x) the
skew symmetric part (x - t(x))/2 of a square matrix x,
more efficiently for specific Matrix classes.
Note that x == symmpart(x) + skewpart(x) for all square
matrices – apart from extraneous NA values in the RHS.
symmpart(x) skewpart(x)
x |
a square matrix; either “traditional” of class
|
These are generic functions with several methods for different matrix
classes, use e.g., showMethods(symmpart) to see them.
If the row and column names differ, the result will use the column
names unless they are (partly) NULL where the row names are
non-NULL (see also the examples).
symmpart() returns a symmetric matrix, inheriting from
symmetricMatrix iff x inherited from
Matrix.
skewpart() returns a skew-symmetric matrix,
typically of the same class as x (or the closest
“general” one, see generalMatrix).
m <- Matrix(1:4, 2,2)
symmpart(m)
skewpart(m)
stopifnot(all(m == symmpart(m) + skewpart(m)))
dn <- dimnames(m) <- list(row = c("r1", "r2"), col = c("var.1", "var.2"))
stopifnot(all(m == symmpart(m) + skewpart(m)))
colnames(m) <- NULL
stopifnot(all(m == symmpart(m) + skewpart(m)))
dimnames(m) <- unname(dn)
stopifnot(all(m == symmpart(m) + skewpart(m)))
## investigate the current methods:
showMethods(skewpart, include = TRUE)