Norm of a Hermitian Matrix
DESCRIPTION:
Computes either the one or infinity norm, the Frobenius norm, or the maximum modulus among elements of a real symmetric or complex Hermitian matrix.
USAGE: 
norm.Hermitian(x, type="M", lower=T)
REQUIRED ARGUMENTS:
x:
a real symmetric or complex Hermitian Matrix inheriting from classes "Hermitian" and "Matrix".
OPTIONAL ARGUMENTS:
type:
A character indication the type of norm desired. "1" or "I" indicates the one or infinity norm (maximum absolute column or row sum), "F" indicates the Frobenius seminorm (the Euclidean norm of x treated as if it were a vector), and "M" indicates the maximum modulus of all the elements in x. The default is "M"
lower:
A logical variable telling whether to use the lower or upper triangle of the matrix for the computation. The default is to select the lower triangle.
VALUE:
A numeric value of class "norm", representing the quantity chosen according to type. A copy of the call to "norm" is returned as an attribute.
DETAILS:
Based on the functions dlansy and zlanhe from Lapack (Anderson et al. (1994)).
REFERENCES:
Anderson, E., et al. (1994). LAPACK User's Guide, 2nd edition, SIAM, Philadelphia. Golub, G., and Van Loan, C. F. (1989). Matrix Computations, 2nd edition, Johns Hopkins, Baltimore.
SEE ALSO:
Matrix , Matrix.class , norm .
EXAMPLES: 
x <- Matrix( sample(-3:3, size = 9, replace = T), nrow = 3, ncol = 3)
x[row(x) > col(x)] <- t(x)[row(x) > col(x)]  # construct symmetric matrix
class(x) <- Matrix.class(x)
norm(x, "1")
norm(x, "I")
norm(x, "F")
norm(x, "M")