isSymmetric {base}R Documentation

Test if a Matrix or other Object is Symmetric


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


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


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.


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.


logical indicating if object is symmetric or not.

See Also

eigen which calls isSymmetric when its symmetric argument is missing, as per default.


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

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

[Package base version 2.5.0 Index]