XLPack 6.1
Excel VBA Numerical Library Reference Manual
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◆ Zlanht()

Function Zlanht ( Norm As  String,
N As  Long,
D() As  Double,
E() As  Complex,
Optional Info As  Long 
)

One norm, Frobenius norm, infinity norm, or largest absolute value of any element of a Hermitian tridiagonal matrix

Purpose
This routine returns the value of the one norm, the Frobenius norm, the infinity norm, or the largest absolute value of any element of a Hermitian tridiagonal matrix A.
Returns
Double
max(abs(Aij)) when Norm = "M",
norm1(A) when Norm = "1" or "O",
normI(A) when Norm = "I", or
normF(A) when Norm = "F" or "E"

where norm1 denotes the one norm of a matrix (maximum column sum), normI denotes the infinity norm of a matrix (maximum row sum) and normF denotes the Frobenius norm of a matrix (square root of sum of squares). Note that max(abs(Aij)) is not a consistent matrix norm.
Parameters
[in]NormSpecifies the value to be returned by Zlanht as described above. Note that normI(A) = norm1(A) since A is Hermitian.
[in]NOrder of the matrix A. (N >= 0) (If N = 0, returns 0)
[in]D()Array D(LD - 1) (LD >= N)
Diagonal elements of Hermitian tridiagonal matrix A.
[in]E()Array E(LE - 1) (LE >= N - 1)
Sub-diagonal or super-diagonal elements of Hermitian tridiagonal matrix A.
[out]Info(Optional)
= 0: Successful exit.
= -1: The argument Norm had an illegal value. (Norm <> "M", "1", "O", "I", "F" nor "E")
= -2: The argument N had an illegal value. (N < 0)
= -3: The argument D() is invalid.
= -4: The argument E() is invalid.
Reference
LAPACK