isSymmetric: Test if a Matrix or other Object is Symmetric

In robertzk/monadicbase: The R Base Package

Description

Generic function to test if object is symmetric or not. Currently only a matrix method is implemented.

Usage

isSymmetric(object, ...)
## S3 method for class 'matrix'
isSymmetric(object, tol = 100 * .Machine$double.eps, ...)

Arguments

object	any R object; a matrix for the matrix method.
tol	numeric scalar >= 0. Smaller differences are not considered, see all.equal.numeric.
...	further arguments passed to methods; the matrix method passes these to all.equal.

Details

The matrix method is used inside eigen by default to test symmetry of matrices up to rounding error, using all.equal. It might not be appropriate in all situations.

Note that a matrix m is only symmetric if its rownames and colnames are identical. Consider using unname(m).

Value

logical indicating if object is symmetric or not.

See Also

eigen which calls isSymmetric when its symmetric argument is missing.

Examples

isSymmetric(D3 <- diag(3)) # -> TRUE

D3[2, 1] <- 1e-100
D3
isSymmetric(D3) # TRUE
isSymmetric(D3, tol = 0) # FALSE for zero-tolerance

robertzk/monadicbase documentation built on May 27, 2019, 10:35 a.m.