isSymmetric
Test if an Object is Symmetric
Description
Tests if a matrix or other object is symmetric (or, for complex values,
Hermitian).
Usage
isSymmetric(object, ...)
isSymmetric.matrix(object, tol = 100 * .Machine$double.eps, ...)
Arguments
| object |
any object, but currently only matrices are supported.
|
| ... |
additional arguments passed to the generic method.
|
| tol |
tolerance used when comparing numeric values.
|
Details
isSymmetric is generic and has a method implemented for class
matrix. It has no default method, so all other object types
generate an error.
A matrix is considered symmetric if it is equal to its own transpose. A
complex matrix is considered Herimitian if it is equal to its own
conjugate transpose.
Note that the symmetry also applies to the dimnames.
Value
returns TRUE if object is a symmetric matrix. Otherwise,
it returns FALSE.
See Also
Examples
m <- diag(3)
m[1,3] <- 1e-20
isSymmetric(m) # TRUE
isSymmetric(m, tol=0) # FALSE
m <- matrix(0+0i, 3,3)
m[1,3] <- 1+2i
m[3,1] <- 1-2i
isSymmetric(m) # TRUE
x <- rbind(c(1,2,3), c(2,2,4), c(3,4,5))
isSymmetric(x) # TRUE
dimnames(x) <- list(c("r1", "r2", "r3"), c("c1", "c2", "c3"))
isSymmetric(x) # FALSE