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isSymmetric {base}

Test if a Matrix or other Object is Symmetric
Package: 
base
Version: 
R 3.0.1

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 is only symmetric if its rownames and colnames are identical.

Values

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

Documentation reproduced from R 3.0.1. License: GPL-2.