CLANHT(3)

okay bestie, welcome to CLANHT(3) from the Library Functions Manual — this page is giving “I know norms and I’m not sorry” energy ✨💅

💖 NAME 💖

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/clanht.f

that’s the whole NAME section, no cap 🫶

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

• real function CLANHT (norm, n, d, e) — CLANHT returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian tridiagonal matrix.

💅 Function/Subroutine Documentation 💅

the full signature is literally:

real function CLANHT (character norm, integer n, real, dimension( * ) d,
       complex, dimension( * ) e)

and the description hits again: CLANHT returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian tridiagonal matrix. iconic behavior, honestly.

🎀 Purpose 🎀

the source says, in its own dramatic little comment block: CLANHT returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a complex Hermitian tridiagonal matrix A.

translation: it’s norm o’clock and A is a complex Hermitian tridiagonal matrix 💅

🌸 Returns 🌸

CLANHT returns this exact menu, bestie:

CLANHT = ( max(abs(A(i,j))), NORM = 'M' or 'm'
         (
         ( norm1(A),         NORM = '1', 'O' or 'o'
         (
         ( normI(A),         NORM = 'I' or 'i'
         (
         ( normF(A),         NORM = 'F', 'f', 'E' 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(A(i,j))) is not a consistent matrix norm. do not come for me, I’m just reporting the facts 😭

💖 Parameters 💖

• NORM — NORM is CHARACTER*1. It specifies the value to be returned in CLANHT as described above. pick your norm, bestie ✨
• N — N is INTEGER. The order of the matrix A. N >= 0. When N = 0, CLANHT is set to zero. zero case is handled, no stress.
• D — D is REAL array, dimension (N). The diagonal elements of A. the main-character diagonal 🎀
• E — E is COMPLEX array, dimension (N-1). The (n-1) sub-diagonal or super-diagonal elements of A. side-character energy, but make it complex.

👑 Author 👑

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 100 of file clanht.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

---

final source/version/date sign-off: this footer says LAPACK Version 3.12.0, with footer path /home/abui...RC/clanht.f(3), and date? not shown in this footer — so we are absolutely not inventing one, bestie 😭🫶💜